feat(share): custom /l/:alias pretty links (share_aliases table) (#205)

Add a retargetable, human-readable vanity link namespace /l/<alias> that
sits alongside the untouched /share/... routes.

- New share_aliases table (workspace-scoped, UNIQUE(workspace_id, alias),
  page_id nullable ON DELETE SET NULL so the address outlives its target).
- ShareAliasRepo + ShareAliasService (create / no-op / 409 reassign guard /
  availability / request-time readable-target resolution through the single
  existing share boundary).
- Public ShareAliasRedirectController (GET /l/:alias) issues a 302 (never 301,
  the target is mutable) to the canonical /share/:key/p/:slug page; unknown /
  dangling / no-longer-readable aliases serve the SPA index with no leak.
  'l/:alias' excluded from the global /api prefix.
- Authenticated ShareAliasController (set/remove/availability/for-page).
- Shared ASCII-only normalize/validate util (server + client copies).
- Client: Custom address block in the share modal (live normalize + debounced
  availability + copy + reassign confirmation dialog).
- Unit tests: util, repo SQL-shape, service semantics, migration/entity sanity
  (server jest) + client alias util (vitest).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/client/src/features/share/components/share-alias-section.tsx

@@ -0,0 +1,237 @@
+import {
+  ActionIcon,
+  Button,
+  Group,
+  Modal,
+  Text,
+  TextInput,
+} from "@mantine/core";
+import { IconExternalLink } from "@tabler/icons-react";
+import { useEffect, useMemo, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
+import CopyTextButton from "@/components/common/copy.tsx";
+import { getAppUrl } from "@/lib/config.ts";
+import {
+  useRemoveShareAliasMutation,
+  useSetShareAliasMutation,
+  useShareAliasForPageQuery,
+} from "@/features/share/queries/share-query.ts";
+import { checkShareAliasAvailability } from "@/features/share/services/share-service.ts";
+import {
+  isValidShareAlias,
+  normalizeShareAlias,
+} from "@/features/share/share-alias.util.ts";
+
+interface ShareAliasSectionProps {
+  pageId: string;
+  readOnly: boolean;
+}
+
+// The prefix label shown next to the slug input, e.g. "docs.example.com/l/".
+function aliasPrefixLabel(): string {
+  const url = getAppUrl();
+  const host = url.replace(/^https?:\/\//, "").replace(/\/+$/, "");
+  return `${host}/l/`;
+}
+
+export default function ShareAliasSection({
+  pageId,
+  readOnly,
+}: ShareAliasSectionProps) {
+  const { t } = useTranslation();
+  const { data: currentAlias } = useShareAliasForPageQuery(pageId);
+  const setAliasMutation = useSetShareAliasMutation();
+  const removeAliasMutation = useRemoveShareAliasMutation();
+
+  const [value, setValue] = useState("");
+  const [availability, setAvailability] = useState<{
+    valid: boolean;
+    available: boolean;
+    currentPageId: string | null;
+  } | null>(null);
+  const [reassign, setReassign] = useState<{
+    alias: string;
+    currentPageTitle: string | null;
+  } | null>(null);
+
+  // Seed the input from the page's current alias (if any).
+  useEffect(() => {
+    setValue(currentAlias?.alias ?? "");
+  }, [currentAlias?.alias, pageId]);
+
+  const normalized = useMemo(() => normalizeShareAlias(value), [value]);
+  const isValid = isValidShareAlias(normalized);
+  const unchanged = currentAlias?.alias === normalized;
+
+  // Debounced availability probe (skips when invalid or unchanged).
+  const debounceRef = useRef<ReturnType<typeof setTimeout>>();
+  useEffect(() => {
+    setAvailability(null);
+    if (!isValid || unchanged) return;
+    debounceRef.current && clearTimeout(debounceRef.current);
+    debounceRef.current = setTimeout(async () => {
+      try {
+        const res = await checkShareAliasAvailability(normalized);
+        setAvailability({
+          valid: res.valid,
+          available: res.available,
+          currentPageId: res.currentPageId,
+        });
+      } catch {
+        setAvailability(null);
+      }
+    }, 400);
+    return () => {
+      debounceRef.current && clearTimeout(debounceRef.current);
+    };
+  }, [normalized, isValid, unchanged]);
+
+  const prettyLink = currentAlias?.alias
+    ? `${getAppUrl()}/l/${currentAlias.alias}`
+    : null;
+
+  const handleSave = async (confirmReassign = false) => {
+    try {
+      await setAliasMutation.mutateAsync({
+        pageId,
+        alias: normalized,
+        confirmReassign,
+      });
+      setReassign(null);
+    } catch (error: any) {
+      // The address already points at another page: prompt to move it here.
+      if (error?.status === 409 || error?.response?.status === 409) {
+        const data = error?.response?.data;
+        if (data?.code === "ALIAS_REASSIGN_REQUIRED") {
+          setReassign({
+            alias: normalized,
+            currentPageTitle: data?.currentPageTitle ?? null,
+          });
+        }
+      }
+    }
+  };
+
+  const handleRemove = async () => {
+    if (!currentAlias?.id) return;
+    await removeAliasMutation.mutateAsync(currentAlias.id);
+    setValue("");
+  };
+
+  const showInvalid = normalized.length > 0 && !isValid;
+  const showTaken =
+    isValid && !unchanged && availability && !availability.available;
+
+  return (
+    <>
+      <Text size="sm" fw={500} mt="md">
+        {t("Custom address")}
+      </Text>
+      <Text size="xs" c="dimmed" mb={4}>
+        {t("A short, memorable link you can point at any shared page.")}
+      </Text>
+
+      {prettyLink && (
+        <Group my="xs" gap={4} wrap="nowrap">
+          <TextInput
+            variant="filled"
+            value={prettyLink}
+            readOnly
+            rightSection={<CopyTextButton text={prettyLink} />}
+            style={{ width: "100%" }}
+          />
+          <ActionIcon
+            component="a"
+            variant="default"
+            target="_blank"
+            href={prettyLink}
+            size="sm"
+          >
+            <IconExternalLink size={16} />
+          </ActionIcon>
+        </Group>
+      )}
+
+      <TextInput
+        value={value}
+        onChange={(e) => setValue(e.currentTarget.value)}
+        // Show the canonical form once the user pauses so what they type maps
+        // visibly to what gets stored.
+        onBlur={() => setValue(normalized)}
+        leftSection={
+          <Text size="xs" c="dimmed" pl={4} style={{ whiteSpace: "nowrap" }}>
+            {aliasPrefixLabel()}
+          </Text>
+        }
+        leftSectionWidth={Math.min(aliasPrefixLabel().length * 7 + 12, 180)}
+        placeholder={t("my-page")}
+        disabled={readOnly}
+        error={
+          showInvalid
+            ? t("Use 2-60 lowercase letters, digits and hyphens")
+            : showTaken
+              ? t("This address is already in use")
+              : undefined
+        }
+      />
+
+      <Group mt="xs" gap="xs">
+        <Button
+          size="compact-sm"
+          onClick={() => handleSave(false)}
+          loading={setAliasMutation.isPending}
+          disabled={readOnly || !isValid || unchanged}
+        >
+          {t("Save")}
+        </Button>
+        {currentAlias?.id && (
+          <Button
+            size="compact-sm"
+            variant="default"
+            color="red"
+            onClick={handleRemove}
+            loading={removeAliasMutation.isPending}
+            disabled={readOnly}
+          >
+            {t("Remove")}
+          </Button>
+        )}
+      </Group>
+
+      <Modal
+        opened={!!reassign}
+        onClose={() => setReassign(null)}
+        title={t("Move custom address?")}
+        centered
+        size="sm"
+      >
+        <Text size="sm">
+          {reassign?.currentPageTitle
+            ? t(
+                'The address "{{alias}}" currently points to "{{title}}". Move it to this page?',
+                {
+                  alias: reassign?.alias,
+                  title: reassign?.currentPageTitle,
+                },
+              )
+            : t(
+                'The address "{{alias}}" is already in use. Move it to this page?',
+                { alias: reassign?.alias },
+              )}
+        </Text>
+        <Group justify="flex-end" mt="md">
+          <Button variant="default" onClick={() => setReassign(null)}>
+            {t("Cancel")}
+          </Button>
+          <Button
+            color="red"
+            onClick={() => handleSave(true)}
+            loading={setAliasMutation.isPending}
+          >
+            {t("Move here")}
+          </Button>
+        </Group>
+      </Modal>
+    </>
+  );
+}

apps/client/src/features/share/components/share-modal.tsx

@@ -25,6 +25,7 @@ import CopyTextButton from "@/components/common/copy.tsx";
 import { getAppUrl } from "@/lib/config.ts";
 import { buildPageUrl } from "@/features/page/page.utils.ts";
 import classes from "@/features/share/components/share.module.css";
+import ShareAliasSection from "@/features/share/components/share-alias-section.tsx";
 import { useAtom } from "jotai";
 import { workspaceAtom } from "@/features/user/atoms/current-user-atom.ts";
 import { useSpaceQuery } from "@/features/space/queries/space-query.ts";
@@ -253,6 +254,9 @@ export default function ShareModal({ readOnly }: ShareModalProps) {
                     disabled={readOnly}
                   />
                 </Group>
+                {pageId && (
+                  <ShareAliasSection pageId={pageId} readOnly={readOnly} />
+                )}
               </>
             )}
           </>

apps/client/src/features/share/queries/share-query.ts

@@ -10,6 +10,8 @@ import { useTranslation } from "react-i18next";
 import {
   ICreateShare,
   IShare,
+  IShareAlias,
+  ISetShareAlias,
   ISharedItem,
   ISharedPage,
   ISharedPageTree,
@@ -20,11 +22,14 @@ import {
 import {
   createShare,
   deleteShare,
+  getShareAliasForPage,
   getSharedPageTree,
   getShareForPage,
   getShareInfo,
   getSharePageInfo,
   getShares,
+  removeShareAlias,
+  setShareAlias,
   updateShare,
 } from "@/features/share/services/share-service.ts";
 import { IPagination, QueryParams } from "@/lib/types.ts";
@@ -170,6 +175,72 @@ export function useDeleteShareMutation() {
   });
 }
 
+export function useShareAliasForPageQuery(
+  pageId: string,
+): UseQueryResult<IShareAlias | null, Error> {
+  return useQuery({
+    // The endpoint resolves to null when the page has no alias; normalize the
+    // absence so React Query never sees `undefined`.
+    queryKey: ["share-alias-for-page", pageId],
+    queryFn: async () => (await getShareAliasForPage(pageId)) ?? null,
+    enabled: !!pageId,
+    staleTime: 60 * 1000,
+    retry: false,
+  });
+}
+
+export function useSetShareAliasMutation() {
+  const { t } = useTranslation();
+  const queryClient = useQueryClient();
+
+  return useMutation<IShareAlias, Error, ISetShareAlias>({
+    mutationFn: (data) => setShareAlias(data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({
+        predicate: (item) =>
+          ["share-alias-for-page", "share-list"].includes(
+            item.queryKey[0] as string,
+          ),
+      });
+    },
+    onError: (error) => {
+      // A 409 reassign-required is handled inline by the modal (it shows the
+      // "move address here?" confirmation), so don't surface a generic toast.
+      if (error?.["status"] === 409) return;
+      notifications.show({
+        message:
+          error?.["response"]?.data?.message || t("Failed to set custom address"),
+        color: "red",
+      });
+    },
+  });
+}
+
+export function useRemoveShareAliasMutation() {
+  const { t } = useTranslation();
+  const queryClient = useQueryClient();
+
+  return useMutation<void, Error, string>({
+    mutationFn: (aliasId) => removeShareAlias(aliasId),
+    onSuccess: () => {
+      queryClient.invalidateQueries({
+        predicate: (item) =>
+          ["share-alias-for-page", "share-list"].includes(
+            item.queryKey[0] as string,
+          ),
+      });
+    },
+    onError: (error) => {
+      notifications.show({
+        message:
+          error?.["response"]?.data?.message ||
+          t("Failed to remove custom address"),
+        color: "red",
+      });
+    },
+  });
+}
+
 export function useGetSharedPageTreeQuery(
   shareId: string,
 ): UseQueryResult<ISharedPageTree, Error> {

apps/client/src/features/share/services/share-service.ts

@@ -4,6 +4,9 @@ import { IPage } from "@/features/page/types/page.types";
 import {
   ICreateShare,
   IShare,
+  IShareAlias,
+  IShareAliasAvailability,
+  ISetShareAlias,
   ISharedItem,
   ISharedPage,
   ISharedPageTree,
@@ -57,3 +60,33 @@ export async function getSharedPageTree(
   const req = await api.post<ISharedPageTree>("/shares/tree", { shareId });
   return req.data;
 }
+
+export async function getShareAliasForPage(
+  pageId: string,
+): Promise<IShareAlias | null> {
+  const req = await api.post<IShareAlias | null>("/share-aliases/for-page", {
+    pageId,
+  });
+  return req.data;
+}
+
+export async function setShareAlias(
+  data: ISetShareAlias,
+): Promise<IShareAlias> {
+  const req = await api.post<IShareAlias>("/share-aliases/set", data);
+  return req.data;
+}
+
+export async function removeShareAlias(aliasId: string): Promise<void> {
+  await api.post("/share-aliases/remove", { aliasId });
+}
+
+export async function checkShareAliasAvailability(
+  alias: string,
+): Promise<IShareAliasAvailability> {
+  const req = await api.post<IShareAliasAvailability>(
+    "/share-aliases/availability",
+    { alias },
+  );
+  return req.data;
+}

apps/client/src/features/share/share-alias.util.test.ts

@@ -0,0 +1,32 @@
+import { describe, it, expect } from "vitest";
+import {
+  isValidShareAlias,
+  normalizeShareAlias,
+} from "@/features/share/share-alias.util.ts";
+
+// Mirrors the server-side util so the modal's live feedback matches what the
+// server will accept/store.
+describe("normalizeShareAlias", () => {
+  it("lowercases, trims and maps separators to single hyphens", () => {
+    expect(normalizeShareAlias("  My  Cool_Page ")).toBe("my-cool-page");
+  });
+
+  it("collapses repeated hyphens and trims edges", () => {
+    expect(normalizeShareAlias("--a---b--")).toBe("a-b");
+  });
+});
+
+describe("isValidShareAlias", () => {
+  it("accepts ascii hyphen-separated slugs of length 2..60", () => {
+    expect(isValidShareAlias("hello-world")).toBe(true);
+    expect(isValidShareAlias("a".repeat(60))).toBe(true);
+  });
+
+  it("rejects too short, edge/double hyphens, uppercase and non-ascii", () => {
+    expect(isValidShareAlias("a")).toBe(false);
+    expect(isValidShareAlias("-a")).toBe(false);
+    expect(isValidShareAlias("a--b")).toBe(false);
+    expect(isValidShareAlias("Hello")).toBe(false);
+    expect(isValidShareAlias("привет")).toBe(false);
+  });
+});

apps/client/src/features/share/share-alias.util.ts

@@ -0,0 +1,26 @@
+/**
+ * Client copy of the vanity share-alias helpers. Kept in sync with the server
+ * (`apps/server/src/core/share/share-alias.util.ts`) so live input feedback
+ * matches what the server will store/accept. ASCII-only, lowercase, hyphen
+ * separated, length 2..60.
+ */
+
+// Normalize a user-provided vanity alias into canonical ASCII storage form.
+export function normalizeShareAlias(raw: string): string {
+  return (raw ?? "")
+    .trim()
+    .toLowerCase()
+    .replace(/[\s_]+/g, "-")
+    .replace(/-{2,}/g, "-")
+    .replace(/^-+|-+$/g, "");
+}
+
+const ALIAS_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
+export function isValidShareAlias(alias: string): boolean {
+  return (
+    typeof alias === "string" &&
+    alias.length >= 2 &&
+    alias.length <= 60 &&
+    ALIAS_RE.test(alias)
+  );
+}

apps/client/src/features/share/types/share.types.ts

@@ -75,6 +75,30 @@ export interface IShareInfoInput {
   pageId: string;
 }
 
+// Vanity /l/:alias pointer.
+export interface IShareAlias {
+  id: string;
+  workspaceId: string;
+  alias: string;
+  pageId: string | null;
+  creatorId: string | null;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface ISetShareAlias {
+  pageId: string;
+  alias: string;
+  confirmReassign?: boolean;
+}
+
+export interface IShareAliasAvailability {
+  alias: string;
+  valid: boolean;
+  available: boolean;
+  currentPageId: string | null;
+}
+
 export interface ISharedPageTree {
   share: IShare;
   pageTree: Partial<IPage[]>;

apps/server/src/core/share/dto/share-alias.dto.ts

@@ -0,0 +1,44 @@
+import {
+  IsBoolean,
+  IsNotEmpty,
+  IsOptional,
+  IsString,
+} from 'class-validator';
+
+/**
+ * Create/retarget a vanity alias for a page. `confirmReassign` is the
+ * two-step guard for the "address already points at another page" case: the
+ * first call without it gets a 409 carrying the current target, the client
+ * confirms, and retries with `confirmReassign: true`.
+ */
+export class SetShareAliasDto {
+  @IsString()
+  @IsNotEmpty()
+  pageId: string;
+
+  @IsString()
+  @IsNotEmpty()
+  alias: string;
+
+  @IsBoolean()
+  @IsOptional()
+  confirmReassign?: boolean;
+}
+
+export class RemoveShareAliasDto {
+  @IsString()
+  @IsNotEmpty()
+  aliasId: string;
+}
+
+export class ShareAliasAvailabilityDto {
+  @IsString()
+  @IsNotEmpty()
+  alias: string;
+}
+
+export class ShareAliasForPageDto {
+  @IsString()
+  @IsNotEmpty()
+  pageId: string;
+}

apps/server/src/core/share/share-alias-redirect.controller.ts

@@ -0,0 +1,97 @@
+import { Controller, Get, Logger, Param, Req, Res } from '@nestjs/common';
+import { FastifyReply, FastifyRequest } from 'fastify';
+import { join } from 'path';
+import * as fs from 'node:fs';
+import slugify from '@sindresorhus/slugify';
+import { WorkspaceRepo } from '@docmost/db/repos/workspace/workspace.repo';
+import { EnvironmentService } from '../../integrations/environment/environment.service';
+import { Workspace } from '@docmost/db/types/entity.types';
+import { ShareAliasService } from './share-alias.service';
+
+/**
+ * Public resolver for vanity links `GET /l/:alias`. Excluded from the global
+ * `/api` prefix (see main.ts) and parallel to ShareSeoController.
+ *
+ * On a hit it issues a 302 (NEVER 301) to the canonical
+ * `/share/:key/p/:slug` page, so:
+ *   - the existing share render + SSR meta is reused verbatim (crawlers follow
+ *     the 302 and get the correct preview);
+ *   - because the alias target is mutable, a temporary redirect is always
+ *     re-resolved — a cached 301 would pin clients to the pre-swap page.
+ *
+ * Any unknown / dangling / no-longer-readable alias serves the plain SPA index
+ * (same as any unknown path) so the existence of a name never leaks.
+ */
+@Controller('l')
+export class ShareAliasRedirectController {
+  private readonly logger = new Logger(ShareAliasRedirectController.name);
+
+  constructor(
+    private readonly shareAliasService: ShareAliasService,
+    private readonly workspaceRepo: WorkspaceRepo,
+    private readonly environmentService: EnvironmentService,
+  ) {}
+
+  @Get(':alias')
+  async resolve(
+    @Param('alias') rawAlias: string,
+    @Req() req: FastifyRequest,
+    @Res({ passthrough: false }) res: FastifyReply,
+  ) {
+    // NestJS does not apply middlewares to paths excluded from the global /api
+    // prefix, so the DomainMiddleware workspace resolution is duplicated here
+    // (same workaround as ShareSeoController).
+    let workspace: Workspace = null;
+    if (this.environmentService.isSelfHosted()) {
+      workspace = await this.workspaceRepo.findFirst();
+    } else {
+      const header = req.raw.headers.host;
+      const subdomain = header?.split('.')[0];
+      workspace = subdomain
+        ? await this.workspaceRepo.findByHostname(subdomain)
+        : null;
+    }
+
+    const clientDistPath = join(__dirname, '..', '..', '..', '..', 'client/dist');
+    const indexFilePath = join(clientDistPath, 'index.html');
+
+    let decoded = rawAlias;
+    try {
+      decoded = decodeURIComponent(rawAlias);
+    } catch {
+      // Malformed percent-encoding -> treat as unknown alias.
+    }
+
+    const resolved = workspace
+      ? await this.shareAliasService.resolveReadableTarget(
+          decoded,
+          workspace.id,
+        )
+      : null;
+
+    if (!resolved) {
+      return this.sendIndex(indexFilePath, res);
+    }
+
+    const slug = buildPageSlug(resolved.page.slugId, resolved.page.title);
+    // 302, NOT 301: the alias is retargetable, so the redirect must always be
+    // re-resolved by clients/crawlers.
+    return res.redirect(`/share/${resolved.share.key}/p/${slug}`, 302);
+  }
+
+  private sendIndex(indexFilePath: string, res: FastifyReply) {
+    if (!fs.existsSync(indexFilePath)) {
+      // No built client (e.g. API-only dev): nothing to serve.
+      res.status(404).send('Not found');
+      return;
+    }
+    const stream = fs.createReadStream(indexFilePath);
+    res.type('text/html').send(stream);
+  }
+}
+
+/** Canonical share page slug: `<title-slug>-<slugId>` (mirrors the client). */
+function buildPageSlug(slugId: string, title?: string): string {
+  const titleSlug = slugify(title?.substring(0, 70) || 'untitled');
+  return `${titleSlug}-${slugId}`;
+}

apps/server/src/core/share/share-alias.controller.ts

@@ -0,0 +1,141 @@
+import {
+  BadRequestException,
+  Body,
+  Controller,
+  ForbiddenException,
+  HttpCode,
+  HttpStatus,
+  NotFoundException,
+  Post,
+  UseGuards,
+} from '@nestjs/common';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { AuthUser } from '../../common/decorators/auth-user.decorator';
+import { AuthWorkspace } from '../../common/decorators/auth-workspace.decorator';
+import { User, Workspace } from '@docmost/db/types/entity.types';
+import { PageRepo } from '@docmost/db/repos/page/page.repo';
+import { PagePermissionRepo } from '@docmost/db/repos/page/page-permission.repo';
+import { PageAccessService } from '../page/page-access/page-access.service';
+import { ShareService } from './share.service';
+import { ShareAliasService } from './share-alias.service';
+import {
+  RemoveShareAliasDto,
+  SetShareAliasDto,
+  ShareAliasAvailabilityDto,
+  ShareAliasForPageDto,
+} from './dto/share-alias.dto';
+
+/**
+ * Authenticated management of vanity `/l/:alias` links. The PUBLIC resolve path
+ * lives in `ShareAliasRedirectController` (`/l/:alias`); this controller only
+ * creates/retargets/removes/looks-up aliases for editors.
+ */
+@UseGuards(JwtAuthGuard)
+@Controller('share-aliases')
+export class ShareAliasController {
+  constructor(
+    private readonly shareAliasService: ShareAliasService,
+    private readonly shareService: ShareService,
+    private readonly pageRepo: PageRepo,
+    private readonly pagePermissionRepo: PagePermissionRepo,
+    private readonly pageAccessService: PageAccessService,
+  ) {}
+
+  @HttpCode(HttpStatus.OK)
+  @Post('set')
+  async set(
+    @Body() dto: SetShareAliasDto,
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+  ) {
+    const page = await this.pageRepo.findById(dto.pageId);
+    if (!page || page.workspaceId !== workspace.id) {
+      throw new NotFoundException('Page not found');
+    }
+
+    // Editing the page is required to point an address at it.
+    await this.pageAccessService.validateCanEdit(page, user);
+
+    // The page must currently be publicly readable through the share graph; an
+    // alias to a non-shared page would only ever 404.
+    const resolved = await this.shareService.resolveReadableSharePage(
+      undefined,
+      page.id,
+      workspace.id,
+    );
+    if (!resolved) {
+      throw new BadRequestException('Page is not publicly shared');
+    }
+
+    const sharingAllowed = await this.shareService.isSharingAllowed(
+      workspace.id,
+      resolved.share.spaceId,
+    );
+    if (!sharingAllowed) {
+      throw new ForbiddenException('Public sharing is disabled');
+    }
+
+    return this.shareAliasService.setAlias({
+      workspaceId: workspace.id,
+      pageId: page.id,
+      creatorId: user.id,
+      alias: dto.alias,
+      confirmReassign: dto.confirmReassign,
+    });
+  }
+
+  @HttpCode(HttpStatus.OK)
+  @Post('remove')
+  async remove(
+    @Body() dto: RemoveShareAliasDto,
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+  ) {
+    const alias = await this.shareAliasService.getAliasById(
+      dto.aliasId,
+      workspace.id,
+    );
+    if (!alias) {
+      throw new NotFoundException('Alias not found');
+    }
+
+    // Only someone who can edit the (current) target page may free the address.
+    // A dangling alias (page deleted) can be removed by any workspace member.
+    if (alias.pageId) {
+      const page = await this.pageRepo.findById(alias.pageId);
+      if (page) {
+        await this.pageAccessService.validateCanEdit(page, user);
+      }
+    }
+
+    await this.shareAliasService.removeAlias(alias.id, workspace.id);
+  }
+
+  @HttpCode(HttpStatus.OK)
+  @Post('availability')
+  async availability(
+    @Body() dto: ShareAliasAvailabilityDto,
+    @AuthWorkspace() workspace: Workspace,
+  ) {
+    return this.shareAliasService.checkAvailability(dto.alias, workspace.id);
+  }
+
+  @HttpCode(HttpStatus.OK)
+  @Post('for-page')
+  async forPage(
+    @Body() dto: ShareAliasForPageDto,
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+  ) {
+    const page = await this.pageRepo.findById(dto.pageId);
+    if (!page || page.workspaceId !== workspace.id) {
+      throw new NotFoundException('Page not found');
+    }
+    await this.pageAccessService.validateCanView(page, user);
+
+    return (
+      (await this.shareAliasService.getAliasForPage(page.id, workspace.id)) ??
+      null
+    );
+  }
+}

apps/server/src/core/share/share-alias.service.spec.ts

@@ -0,0 +1,252 @@
+import { BadRequestException, ConflictException } from '@nestjs/common';
+import { ShareAliasService } from './share-alias.service';
+
+/**
+ * Behaviour tests for the alias write/resolve semantics: create vs no-op vs the
+ * 409 reassign guard, uniqueness-race handling, availability probe, and the
+ * request-time readable-target resolution (which re-runs the share boundary).
+ */
+describe('ShareAliasService', () => {
+  function makeService() {
+    const shareAliasRepo = {
+      findByAliasAndWorkspace: jest.fn(),
+      findByPageId: jest.fn(),
+      findById: jest.fn(),
+      insert: jest.fn(),
+      updatePageId: jest.fn(),
+      delete: jest.fn(),
+    };
+    const pageRepo = { findById: jest.fn() };
+    const shareService = {
+      resolveReadableSharePage: jest.fn(),
+      isSharingAllowed: jest.fn(),
+    };
+    const service = new ShareAliasService(
+      shareAliasRepo as any,
+      pageRepo as any,
+      shareService as any,
+    );
+    return { service, shareAliasRepo, pageRepo, shareService };
+  }
+
+  describe('setAlias', () => {
+    it('rejects an invalid alias before touching the db', async () => {
+      const { service, shareAliasRepo } = makeService();
+      await expect(
+        service.setAlias({
+          workspaceId: 'ws-1',
+          pageId: 'p-1',
+          creatorId: 'u-1',
+          alias: 'A', // too short + uppercase
+        }),
+      ).rejects.toBeInstanceOf(BadRequestException);
+      expect(shareAliasRepo.findByAliasAndWorkspace).not.toHaveBeenCalled();
+    });
+
+    it('normalizes then inserts a brand-new alias', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue(undefined);
+      shareAliasRepo.insert.mockResolvedValue({ id: 'a-1', alias: 'my-page' });
+
+      const res = await service.setAlias({
+        workspaceId: 'ws-1',
+        pageId: 'p-1',
+        creatorId: 'u-1',
+        alias: '  My Page ',
+      });
+
+      expect(shareAliasRepo.findByAliasAndWorkspace).toHaveBeenCalledWith(
+        'my-page',
+        'ws-1',
+      );
+      expect(shareAliasRepo.insert).toHaveBeenCalledWith({
+        workspaceId: 'ws-1',
+        alias: 'my-page',
+        pageId: 'p-1',
+        creatorId: 'u-1',
+      });
+      expect(res).toMatchObject({ id: 'a-1' });
+    });
+
+    it('is a no-op when the alias already points at the same page', async () => {
+      const { service, shareAliasRepo } = makeService();
+      const existing = { id: 'a-1', alias: 'foo', pageId: 'p-1' };
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue(existing);
+
+      const res = await service.setAlias({
+        workspaceId: 'ws-1',
+        pageId: 'p-1',
+        creatorId: 'u-1',
+        alias: 'foo',
+      });
+
+      expect(res).toBe(existing);
+      expect(shareAliasRepo.insert).not.toHaveBeenCalled();
+      expect(shareAliasRepo.updatePageId).not.toHaveBeenCalled();
+    });
+
+    it('throws 409 with current target when name is taken and not confirmed', async () => {
+      const { service, shareAliasRepo, pageRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        alias: 'foo',
+        pageId: 'p-other',
+      });
+      pageRepo.findById.mockResolvedValue({ id: 'p-other', title: 'Other' });
+
+      try {
+        await service.setAlias({
+          workspaceId: 'ws-1',
+          pageId: 'p-1',
+          creatorId: 'u-1',
+          alias: 'foo',
+        });
+        fail('expected ConflictException');
+      } catch (err) {
+        expect(err).toBeInstanceOf(ConflictException);
+        expect((err as ConflictException).getResponse()).toMatchObject({
+          code: 'ALIAS_REASSIGN_REQUIRED',
+          currentPageId: 'p-other',
+          currentPageTitle: 'Other',
+        });
+      }
+      expect(shareAliasRepo.updatePageId).not.toHaveBeenCalled();
+    });
+
+    it('retargets (UPDATE page_id) when confirmReassign is set', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        alias: 'foo',
+        pageId: 'p-other',
+      });
+      shareAliasRepo.updatePageId.mockResolvedValue({ id: 'a-1', pageId: 'p-1' });
+
+      const res = await service.setAlias({
+        workspaceId: 'ws-1',
+        pageId: 'p-1',
+        creatorId: 'u-1',
+        alias: 'foo',
+        confirmReassign: true,
+      });
+
+      expect(shareAliasRepo.updatePageId).toHaveBeenCalledWith(
+        'a-1',
+        'p-1',
+        'ws-1',
+      );
+      expect(res).toMatchObject({ pageId: 'p-1' });
+    });
+
+    it('maps a unique-violation race to 409', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue(undefined);
+      shareAliasRepo.insert.mockRejectedValue({ code: '23505' });
+
+      await expect(
+        service.setAlias({
+          workspaceId: 'ws-1',
+          pageId: 'p-1',
+          creatorId: 'u-1',
+          alias: 'foo',
+        }),
+      ).rejects.toBeInstanceOf(ConflictException);
+    });
+  });
+
+  describe('checkAvailability', () => {
+    it('reports invalid for a bad slug without a db hit', async () => {
+      const { service, shareAliasRepo } = makeService();
+      const res = await service.checkAvailability('Bad Slug!', 'ws-1');
+      expect(res).toMatchObject({ valid: false, available: false });
+      expect(shareAliasRepo.findByAliasAndWorkspace).not.toHaveBeenCalled();
+    });
+
+    it('reports available when no row exists', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue(undefined);
+      const res = await service.checkAvailability('free-name', 'ws-1');
+      expect(res).toMatchObject({
+        alias: 'free-name',
+        valid: true,
+        available: true,
+        currentPageId: null,
+      });
+    });
+
+    it('reports taken with the current target page', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        pageId: 'p-9',
+      });
+      const res = await service.checkAvailability('taken', 'ws-1');
+      expect(res).toMatchObject({ available: false, currentPageId: 'p-9' });
+    });
+  });
+
+  describe('resolveReadableTarget', () => {
+    it('returns null for an invalid alias', async () => {
+      const { service } = makeService();
+      expect(await service.resolveReadableTarget('!!', 'ws-1')).toBeNull();
+    });
+
+    it('returns null for an unknown or dangling alias', async () => {
+      const { service, shareAliasRepo } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValueOnce(undefined);
+      expect(await service.resolveReadableTarget('foo', 'ws-1')).toBeNull();
+
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValueOnce({
+        id: 'a-1',
+        pageId: null,
+      });
+      expect(await service.resolveReadableTarget('foo', 'ws-1')).toBeNull();
+    });
+
+    it('returns null when the page is no longer publicly readable', async () => {
+      const { service, shareAliasRepo, shareService } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        pageId: 'p-1',
+      });
+      shareService.resolveReadableSharePage.mockResolvedValue(null);
+      expect(await service.resolveReadableTarget('foo', 'ws-1')).toBeNull();
+    });
+
+    it('returns null when sharing is disabled for the space', async () => {
+      const { service, shareAliasRepo, shareService } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        pageId: 'p-1',
+      });
+      shareService.resolveReadableSharePage.mockResolvedValue({
+        share: { key: 'k', spaceId: 's-1' },
+        page: { slugId: 'sid', title: 'T' },
+      });
+      shareService.isSharingAllowed.mockResolvedValue(false);
+      expect(await service.resolveReadableTarget('foo', 'ws-1')).toBeNull();
+    });
+
+    it('returns the resolved share+page on success', async () => {
+      const { service, shareAliasRepo, shareService } = makeService();
+      shareAliasRepo.findByAliasAndWorkspace.mockResolvedValue({
+        id: 'a-1',
+        pageId: 'p-1',
+      });
+      const resolved = {
+        share: { key: 'k', spaceId: 's-1' },
+        page: { slugId: 'sid', title: 'T' },
+      };
+      shareService.resolveReadableSharePage.mockResolvedValue(resolved);
+      shareService.isSharingAllowed.mockResolvedValue(true);
+
+      const res = await service.resolveReadableTarget('FOO', 'ws-1');
+      expect(res).toBe(resolved);
+      // alias was normalized to lowercase before lookup
+      expect(shareAliasRepo.findByAliasAndWorkspace).toHaveBeenCalledWith(
+        'foo',
+        'ws-1',
+      );
+    });
+  });
+});

apps/server/src/core/share/share-alias.service.ts

@@ -0,0 +1,187 @@
+import {
+  BadRequestException,
+  ConflictException,
+  Injectable,
+  Logger,
+} from '@nestjs/common';
+import { ShareAliasRepo } from '@docmost/db/repos/share-alias/share-alias.repo';
+import { PageRepo } from '@docmost/db/repos/page/page.repo';
+import { ShareService } from './share.service';
+import { Page, ShareAlias } from '@docmost/db/types/entity.types';
+import { isValidShareAlias, normalizeShareAlias } from './share-alias.util';
+
+/** Postgres unique_violation; the (workspace_id, alias) constraint races here. */
+const PG_UNIQUE_VIOLATION = '23505';
+
+export interface ResolvedAliasTarget {
+  share: NonNullable<
+    Awaited<ReturnType<ShareService['resolveReadableSharePage']>>
+  >['share'];
+  page: Page;
+}
+
+@Injectable()
+export class ShareAliasService {
+  private readonly logger = new Logger(ShareAliasService.name);
+
+  constructor(
+    private readonly shareAliasRepo: ShareAliasRepo,
+    private readonly pageRepo: PageRepo,
+    private readonly shareService: ShareService,
+  ) {}
+
+  /**
+   * Create or retarget a vanity alias. The alias is workspace-scoped:
+   *   - no row for this name        -> INSERT a new pointer
+   *   - row already points at pageId -> no-op (idempotent)
+   *   - row points elsewhere         -> the "swap". Without confirmReassign we
+   *     throw 409 carrying the current target so the client can confirm; with
+   *     it we UPDATE the single row's page_id (every /l/<alias> link follows the
+   *     302 to the new page instantly — no stale 301 cache).
+   *
+   * Caller is responsible for authorizing the page (edit rights + public
+   * readability); this method owns only the alias-name semantics.
+   */
+  async setAlias(opts: {
+    workspaceId: string;
+    pageId: string;
+    creatorId: string;
+    alias: string;
+    confirmReassign?: boolean;
+  }): Promise<ShareAlias> {
+    const { workspaceId, pageId, creatorId, confirmReassign } = opts;
+    const alias = normalizeShareAlias(opts.alias);
+    if (!isValidShareAlias(alias)) {
+      throw new BadRequestException(
+        'Invalid alias. Use 2-60 lowercase letters, digits and hyphens.',
+      );
+    }
+
+    const existing = await this.shareAliasRepo.findByAliasAndWorkspace(
+      alias,
+      workspaceId,
+    );
+
+    if (!existing) {
+      try {
+        return await this.shareAliasRepo.insert({
+          workspaceId,
+          alias,
+          pageId,
+          creatorId,
+        });
+      } catch (err: any) {
+        // Lost a uniqueness race: another request claimed the name first.
+        if (err?.code === PG_UNIQUE_VIOLATION) {
+          throw new ConflictException({ message: 'Alias already taken' });
+        }
+        this.logger.error(err);
+        throw new BadRequestException('Failed to set alias');
+      }
+    }
+
+    // Already points at this page -> nothing to do.
+    if (existing.pageId === pageId) {
+      return existing;
+    }
+
+    // Name occupied by a different (or dangling) target: require confirmation.
+    if (!confirmReassign) {
+      const currentPage = existing.pageId
+        ? await this.pageRepo.findById(existing.pageId)
+        : null;
+      throw new ConflictException({
+        message: 'Alias already in use',
+        code: 'ALIAS_REASSIGN_REQUIRED',
+        currentPageId: existing.pageId,
+        currentPageTitle: currentPage?.title ?? null,
+      });
+    }
+
+    return this.shareAliasRepo.updatePageId(existing.id, pageId, workspaceId);
+  }
+
+  /** Free a vanity name (no history kept). */
+  async removeAlias(aliasId: string, workspaceId: string): Promise<void> {
+    await this.shareAliasRepo.delete(aliasId, workspaceId);
+  }
+
+  /** Debounced availability probe for the modal. */
+  async checkAvailability(
+    rawAlias: string,
+    workspaceId: string,
+  ): Promise<{
+    alias: string;
+    valid: boolean;
+    available: boolean;
+    currentPageId: string | null;
+  }> {
+    const alias = normalizeShareAlias(rawAlias);
+    if (!isValidShareAlias(alias)) {
+      return { alias, valid: false, available: false, currentPageId: null };
+    }
+    const existing = await this.shareAliasRepo.findByAliasAndWorkspace(
+      alias,
+      workspaceId,
+    );
+    return {
+      alias,
+      valid: true,
+      available: !existing,
+      currentPageId: existing?.pageId ?? null,
+    };
+  }
+
+  /** A single alias row scoped to the workspace, or undefined. */
+  getAliasById(
+    aliasId: string,
+    workspaceId: string,
+  ): Promise<ShareAlias | undefined> {
+    return this.shareAliasRepo.findById(aliasId, workspaceId);
+  }
+
+  /** The alias currently targeting a page (modal display), or undefined. */
+  getAliasForPage(
+    pageId: string,
+    workspaceId: string,
+  ): Promise<ShareAlias | undefined> {
+    return this.shareAliasRepo.findByPageId(pageId, workspaceId);
+  }
+
+  /**
+   * Resolve a vanity alias to the canonical, publicly-READABLE share page, or
+   * null. This re-runs the authoritative share boundary at request time (so a
+   * later-unshared / restricted / sharing-disabled target collapses to null and
+   * the caller serves the generic SPA 404 — no existence leak). The alias row
+   * itself is just a pointer; this is where access is actually decided.
+   */
+  async resolveReadableTarget(
+    rawAlias: string,
+    workspaceId: string,
+  ): Promise<ResolvedAliasTarget | null> {
+    const alias = normalizeShareAlias(rawAlias);
+    if (!isValidShareAlias(alias)) return null;
+
+    const aliasRow = await this.shareAliasRepo.findByAliasAndWorkspace(
+      alias,
+      workspaceId,
+    );
+    // Unknown name or a dangling alias (target page deleted) -> not resolvable.
+    if (!aliasRow?.pageId) return null;
+
+    const resolved = await this.shareService.resolveReadableSharePage(
+      undefined,
+      aliasRow.pageId,
+      workspaceId,
+    );
+    if (!resolved) return null;
+
+    const sharingAllowed = await this.shareService.isSharingAllowed(
+      workspaceId,
+      resolved.share.spaceId,
+    );
+    if (!sharingAllowed) return null;
+
+    return resolved;
+  }
+}

apps/server/src/core/share/share-alias.util.spec.ts

@@ -0,0 +1,60 @@
+import { isValidShareAlias, normalizeShareAlias } from './share-alias.util';
+
+describe('normalizeShareAlias', () => {
+  it('lowercases and trims', () => {
+    expect(normalizeShareAlias('  HelloWorld  ')).toBe('helloworld');
+  });
+
+  it('converts spaces and underscores to single hyphens', () => {
+    expect(normalizeShareAlias('my cool   page')).toBe('my-cool-page');
+    expect(normalizeShareAlias('my_cool_page')).toBe('my-cool-page');
+  });
+
+  it('collapses repeated hyphens and trims edge hyphens', () => {
+    expect(normalizeShareAlias('--a---b--')).toBe('a-b');
+  });
+
+  it('handles null/undefined defensively', () => {
+    expect(normalizeShareAlias(undefined as unknown as string)).toBe('');
+  });
+});
+
+describe('isValidShareAlias', () => {
+  it('accepts ascii lowercase hyphen-separated slugs', () => {
+    expect(isValidShareAlias('hello')).toBe(true);
+    expect(isValidShareAlias('hello-world-2')).toBe(true);
+    expect(isValidShareAlias('a1')).toBe(true);
+  });
+
+  it('rejects too short / too long', () => {
+    expect(isValidShareAlias('a')).toBe(false);
+    expect(isValidShareAlias('a'.repeat(61))).toBe(false);
+    expect(isValidShareAlias('a'.repeat(60))).toBe(true);
+  });
+
+  it('rejects leading/trailing/double hyphens', () => {
+    expect(isValidShareAlias('-abc')).toBe(false);
+    expect(isValidShareAlias('abc-')).toBe(false);
+    expect(isValidShareAlias('a--b')).toBe(false);
+  });
+
+  it('rejects uppercase, cyrillic and other non-ascii', () => {
+    expect(isValidShareAlias('Hello')).toBe(false);
+    expect(isValidShareAlias('привет')).toBe(false);
+    expect(isValidShareAlias('a b')).toBe(false);
+    expect(isValidShareAlias('a_b')).toBe(false);
+    expect(isValidShareAlias('a.b')).toBe(false);
+  });
+
+  it('normalize + validate round-trips a messy input to a valid slug', () => {
+    const alias = normalizeShareAlias('  My  Cool_Page!! ');
+    // "!!" is not stripped by normalize (only case/separators), so the result
+    // still fails validation — the charset gate is intentionally separate.
+    expect(alias).toBe('my-cool-page!!');
+    expect(isValidShareAlias(alias)).toBe(false);
+
+    const ok = normalizeShareAlias('  My  Cool Page ');
+    expect(ok).toBe('my-cool-page');
+    expect(isValidShareAlias(ok)).toBe(true);
+  });
+});

apps/server/src/core/share/share-alias.util.ts

@@ -0,0 +1,30 @@
+/**
+ * Vanity share-alias helpers shared by the write path (set/availability) and the
+ * `/l/:alias` resolve path. Aliases are ASCII-only, lowercase, hyphen-separated
+ * slugs — deliberately no Cyrillic / transliteration: the user types the exact
+ * canonical form. Keep this in sync with the client copy in
+ * `apps/client/src/features/share/share-alias.util.ts`.
+ */
+
+// Normalize a user-provided vanity alias into canonical ASCII storage form.
+// This only canonicalizes shape (case, separators); it does NOT enforce the
+// charset — call isValidShareAlias afterwards to reject anything illegal.
+export function normalizeShareAlias(raw: string): string {
+  return (raw ?? '')
+    .trim()
+    .toLowerCase()
+    .replace(/[\s_]+/g, '-') // spaces/underscores -> single hyphen
+    .replace(/-{2,}/g, '-') // collapse repeated hyphens
+    .replace(/^-+|-+$/g, ''); // trim leading/trailing hyphens
+}
+
+// ASCII only: lowercase letters/digits in hyphen-separated groups, length 2..60.
+const ALIAS_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
+export function isValidShareAlias(alias: string): boolean {
+  return (
+    typeof alias === 'string' &&
+    alias.length >= 2 &&
+    alias.length <= 60 &&
+    ALIAS_RE.test(alias)
+  );
+}

apps/server/src/core/share/share.module.ts

@@ -5,13 +5,22 @@ import { TokenModule } from '../auth/token.module';
 import { ShareSeoController } from './share-seo.controller';
 import { TransclusionModule } from '../page/transclusion/transclusion.module';
 import { AiModule } from '../../integrations/ai/ai.module';
+import { ShareAliasService } from './share-alias.service';
+import { ShareAliasController } from './share-alias.controller';
+import { ShareAliasRedirectController } from './share-alias-redirect.controller';
 
 @Module({
   // AiModule (AiSettingsService) is used by the page-info route to surface
   // whether the anonymous public-share assistant is enabled for the workspace.
   imports: [TokenModule, TransclusionModule, AiModule],
-  controllers: [ShareController, ShareSeoController],
-  providers: [ShareService],
-  exports: [ShareService],
+  controllers: [
+    ShareController,
+    ShareSeoController,
+    // Vanity /l/:alias: authenticated management + public 302 resolver.
+    ShareAliasController,
+    ShareAliasRedirectController,
+  ],
+  providers: [ShareService, ShareAliasService],
+  exports: [ShareService, ShareAliasService],
 })
 export class ShareModule {}

apps/server/src/database/database.module.ts

@@ -23,6 +23,7 @@ import { UserTokenRepo } from './repos/user-token/user-token.repo';
 import { UserSessionRepo } from '@docmost/db/repos/session/user-session.repo';
 import { BacklinkRepo } from '@docmost/db/repos/backlink/backlink.repo';
 import { ShareRepo } from '@docmost/db/repos/share/share.repo';
+import { ShareAliasRepo } from '@docmost/db/repos/share-alias/share-alias.repo';
 import { NotificationRepo } from '@docmost/db/repos/notification/notification.repo';
 import { WatcherRepo } from '@docmost/db/repos/watcher/watcher.repo';
 import { LabelRepo } from '@docmost/db/repos/label/label.repo';
@@ -96,6 +97,7 @@ import { normalizePostgresUrl } from '../common/helpers';
     UserSessionRepo,
     BacklinkRepo,
     ShareRepo,
+    ShareAliasRepo,
     NotificationRepo,
     WatcherRepo,
     LabelRepo,
@@ -128,6 +130,7 @@ import { normalizePostgresUrl } from '../common/helpers';
     UserSessionRepo,
     BacklinkRepo,
     ShareRepo,
+    ShareAliasRepo,
     NotificationRepo,
     WatcherRepo,
     LabelRepo,

apps/server/src/database/migrations/20260626T130000-share-aliases.ts

@@ -0,0 +1,54 @@
+import { type Kysely, sql } from 'kysely';
+
+/**
+ * Vanity share aliases: a retargetable, human-readable pointer (`/l/<alias>`)
+ * that lives independently of any single `shares` row. The alias belongs to the
+ * WORKSPACE (stable address), and `page_id` is nullable with ON DELETE SET NULL
+ * so the address survives deletion of its current target (it 404s until
+ * retargeted) rather than disappearing with the page.
+ */
+export async function up(db: Kysely<any>): Promise<void> {
+  await db.schema
+    .createTable('share_aliases')
+    .addColumn('id', 'uuid', (col) =>
+      col.primaryKey().defaultTo(sql`gen_uuid_v7()`),
+    )
+    .addColumn('workspace_id', 'uuid', (col) =>
+      col.references('workspaces.id').onDelete('cascade').notNull(),
+    )
+    // Normalized ASCII, lowercase. Uniqueness is enforced per-workspace below.
+    .addColumn('alias', 'varchar', (col) => col.notNull())
+    // Nullable + SET NULL: the address outlives its target page.
+    .addColumn('page_id', 'uuid', (col) =>
+      col.references('pages.id').onDelete('set null'),
+    )
+    .addColumn('creator_id', 'uuid', (col) =>
+      col.references('users.id').onDelete('set null'),
+    )
+    .addColumn('created_at', 'timestamptz', (col) =>
+      col.notNull().defaultTo(sql`now()`),
+    )
+    .addColumn('updated_at', 'timestamptz', (col) =>
+      col.notNull().defaultTo(sql`now()`),
+    )
+    .execute();
+
+  // The vanity name is unique within a workspace (mirrors shares.key scoping).
+  await db.schema
+    .createIndex('share_aliases_workspace_id_alias_unique')
+    .on('share_aliases')
+    .columns(['workspace_id', 'alias'])
+    .unique()
+    .execute();
+
+  // "Which alias targets this page?" lookup for the share modal.
+  await db.schema
+    .createIndex('share_aliases_page_id_idx')
+    .on('share_aliases')
+    .column('page_id')
+    .execute();
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await db.schema.dropTable('share_aliases').execute();
+}

apps/server/src/database/migrations/share-aliases.migration.spec.ts

@@ -0,0 +1,99 @@
+import * as migration from './20260626T130000-share-aliases';
+import type {
+  InsertableShareAlias,
+  ShareAlias,
+  UpdatableShareAlias,
+} from '../types/entity.types';
+
+/**
+ * Sanity checks for the share_aliases migration + entity types. We don't run a
+ * live Postgres here (that's the integration suite); instead we assert the
+ * migration exposes the expected up/down contract and creates the table with
+ * the unique (workspace_id, alias) constraint and the page_id index, and that
+ * the generated entity types line up with the column set.
+ */
+describe('share-aliases migration', () => {
+  it('exports up and down functions', () => {
+    expect(typeof migration.up).toBe('function');
+    expect(typeof migration.down).toBe('function');
+  });
+
+  it('up creates the table, the unique index and the page_id index', async () => {
+    const calls: string[] = [];
+
+    const tableBuilder: any = new Proxy(
+      {},
+      {
+        get(_t, prop: string) {
+          if (prop === 'execute') return async () => undefined;
+          // addColumn/addConstraint/etc. are chainable no-ops.
+          return () => tableBuilder;
+        },
+      },
+    );
+
+    const indexBuilder: any = new Proxy(
+      {},
+      {
+        get(_t, prop: string) {
+          if (prop === 'execute') return async () => undefined;
+          return () => indexBuilder;
+        },
+      },
+    );
+
+    const schema = {
+      createTable: (name: string) => {
+        calls.push(`createTable:${name}`);
+        return tableBuilder;
+      },
+      createIndex: (name: string) => {
+        calls.push(`createIndex:${name}`);
+        return indexBuilder;
+      },
+    };
+
+    await migration.up({ schema } as any);
+
+    expect(calls).toContain('createTable:share_aliases');
+    expect(calls).toContain(
+      'createIndex:share_aliases_workspace_id_alias_unique',
+    );
+    expect(calls).toContain('createIndex:share_aliases_page_id_idx');
+  });
+
+  it('down drops the table', async () => {
+    const calls: string[] = [];
+    const dropBuilder: any = { execute: async () => undefined };
+    const schema = {
+      dropTable: (name: string) => {
+        calls.push(`dropTable:${name}`);
+        return dropBuilder;
+      },
+    };
+    await migration.down({ schema } as any);
+    expect(calls).toContain('dropTable:share_aliases');
+  });
+
+  it('entity types expose the alias columns', () => {
+    // Compile-time + runtime sanity: a well-formed row/insert/update value.
+    const row: ShareAlias = {
+      id: 'a-1',
+      workspaceId: 'ws-1',
+      alias: 'foo',
+      pageId: 'p-1',
+      creatorId: 'u-1',
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    };
+    const insert: InsertableShareAlias = {
+      workspaceId: 'ws-1',
+      alias: 'foo',
+    };
+    const update: UpdatableShareAlias = { pageId: null };
+
+    expect(row.alias).toBe('foo');
+    expect(insert.workspaceId).toBe('ws-1');
+    expect(update.pageId).toBeNull();
+  });
+});

apps/server/src/database/repos/share-alias/share-alias.repo.spec.ts

@@ -0,0 +1,120 @@
+import { ShareAliasRepo } from './share-alias.repo';
+import type { KyselyDB } from '../../types/kysely.types';
+
+/**
+ * SQL-shape unit tests for ShareAliasRepo. A live Postgres is out of scope;
+ * instead we spy on the Kysely builder to assert each method pins the
+ * workspace scope (so a name in one workspace can never resolve another's
+ * page) and threads the right columns.
+ */
+describe('ShareAliasRepo', () => {
+  function makeSelectRepo(result: unknown) {
+    const where = jest.fn();
+    const builder: any = {
+      select: jest.fn(() => builder),
+      where: jest.fn((...args: unknown[]) => {
+        where(...args);
+        return builder;
+      }),
+      executeTakeFirst: jest.fn().mockResolvedValue(result),
+    };
+    const db = { selectFrom: jest.fn(() => builder) } as unknown as KyselyDB;
+    return { repo: new ShareAliasRepo(db), db, where, builder };
+  }
+
+  it('findByAliasAndWorkspace scopes by alias AND workspace', async () => {
+    const row = { id: 'a-1', alias: 'foo', workspaceId: 'ws-1' };
+    const { repo, db, where } = makeSelectRepo(row);
+
+    const res = await repo.findByAliasAndWorkspace('foo', 'ws-1');
+
+    expect(res).toBe(row);
+    expect(db.selectFrom).toHaveBeenCalledWith('shareAliases');
+    expect(where).toHaveBeenCalledWith('alias', '=', 'foo');
+    expect(where).toHaveBeenCalledWith('workspaceId', '=', 'ws-1');
+  });
+
+  it('findByPageId scopes by page AND workspace', async () => {
+    const { repo, where } = makeSelectRepo(undefined);
+    await repo.findByPageId('p-1', 'ws-1');
+    expect(where).toHaveBeenCalledWith('pageId', '=', 'p-1');
+    expect(where).toHaveBeenCalledWith('workspaceId', '=', 'ws-1');
+  });
+
+  it('insert writes the provided columns and returns the row', async () => {
+    const values = jest.fn();
+    const inserted = { id: 'a-1' };
+    const builder: any = {
+      values: jest.fn((v: unknown) => {
+        values(v);
+        return builder;
+      }),
+      returning: jest.fn(() => builder),
+      executeTakeFirst: jest.fn().mockResolvedValue(inserted),
+    };
+    const db = { insertInto: jest.fn(() => builder) } as unknown as KyselyDB;
+    const repo = new ShareAliasRepo(db);
+
+    const res = await repo.insert({
+      workspaceId: 'ws-1',
+      alias: 'foo',
+      pageId: 'p-1',
+      creatorId: 'u-1',
+    });
+
+    expect(db.insertInto).toHaveBeenCalledWith('shareAliases');
+    expect(values).toHaveBeenCalledWith({
+      workspaceId: 'ws-1',
+      alias: 'foo',
+      pageId: 'p-1',
+      creatorId: 'u-1',
+    });
+    expect(res).toBe(inserted);
+  });
+
+  it('updatePageId retargets a single row scoped by id + workspace', async () => {
+    const set = jest.fn();
+    const where = jest.fn();
+    const builder: any = {
+      set: jest.fn((s: unknown) => {
+        set(s);
+        return builder;
+      }),
+      where: jest.fn((...args: unknown[]) => {
+        where(...args);
+        return builder;
+      }),
+      returning: jest.fn(() => builder),
+      executeTakeFirst: jest.fn().mockResolvedValue({ id: 'a-1' }),
+    };
+    const db = { updateTable: jest.fn(() => builder) } as unknown as KyselyDB;
+    const repo = new ShareAliasRepo(db);
+
+    await repo.updatePageId('a-1', 'p-2', 'ws-1');
+
+    expect(db.updateTable).toHaveBeenCalledWith('shareAliases');
+    expect(set.mock.calls[0][0].pageId).toBe('p-2');
+    expect(set.mock.calls[0][0].updatedAt).toBeInstanceOf(Date);
+    expect(where).toHaveBeenCalledWith('id', '=', 'a-1');
+    expect(where).toHaveBeenCalledWith('workspaceId', '=', 'ws-1');
+  });
+
+  it('delete scopes by id + workspace', async () => {
+    const where = jest.fn();
+    const builder: any = {
+      where: jest.fn((...args: unknown[]) => {
+        where(...args);
+        return builder;
+      }),
+      execute: jest.fn().mockResolvedValue(undefined),
+    };
+    const db = { deleteFrom: jest.fn(() => builder) } as unknown as KyselyDB;
+    const repo = new ShareAliasRepo(db);
+
+    await repo.delete('a-1', 'ws-1');
+
+    expect(db.deleteFrom).toHaveBeenCalledWith('shareAliases');
+    expect(where).toHaveBeenCalledWith('id', '=', 'a-1');
+    expect(where).toHaveBeenCalledWith('workspaceId', '=', 'ws-1');
+  });
+});

apps/server/src/database/repos/share-alias/share-alias.repo.ts

@@ -0,0 +1,109 @@
+import { Injectable } from '@nestjs/common';
+import { InjectKysely } from 'nestjs-kysely';
+import { KyselyDB, KyselyTransaction } from '../../types/kysely.types';
+import { dbOrTx } from '../../utils';
+import {
+  InsertableShareAlias,
+  ShareAlias,
+} from '@docmost/db/types/entity.types';
+
+/**
+ * Repository for vanity share aliases (`/l/:alias`). An alias is a long-lived,
+ * workspace-scoped pointer to a page; retargeting is a single UPDATE of
+ * `page_id`. All lookups are workspace-scoped so a name in one workspace can
+ * never resolve a page in another.
+ */
+@Injectable()
+export class ShareAliasRepo {
+  constructor(@InjectKysely() private readonly db: KyselyDB) {}
+
+  private baseFields: Array<keyof ShareAlias> = [
+    'id',
+    'workspaceId',
+    'alias',
+    'pageId',
+    'creatorId',
+    'createdAt',
+    'updatedAt',
+  ];
+
+  /** Resolve a (normalized) alias within a workspace, or undefined. */
+  async findByAliasAndWorkspace(
+    alias: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<ShareAlias | undefined> {
+    return dbOrTx(this.db, trx)
+      .selectFrom('shareAliases')
+      .select(this.baseFields)
+      .where('alias', '=', alias)
+      .where('workspaceId', '=', workspaceId)
+      .executeTakeFirst();
+  }
+
+  /** The alias currently pointing at a page (for the share modal). */
+  async findByPageId(
+    pageId: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<ShareAlias | undefined> {
+    return dbOrTx(this.db, trx)
+      .selectFrom('shareAliases')
+      .select(this.baseFields)
+      .where('pageId', '=', pageId)
+      .where('workspaceId', '=', workspaceId)
+      .executeTakeFirst();
+  }
+
+  async findById(
+    id: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<ShareAlias | undefined> {
+    return dbOrTx(this.db, trx)
+      .selectFrom('shareAliases')
+      .select(this.baseFields)
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .executeTakeFirst();
+  }
+
+  async insert(
+    insertable: InsertableShareAlias,
+    trx?: KyselyTransaction,
+  ): Promise<ShareAlias> {
+    return dbOrTx(this.db, trx)
+      .insertInto('shareAliases')
+      .values(insertable)
+      .returning(this.baseFields)
+      .executeTakeFirst();
+  }
+
+  /** Retarget an existing alias to a new page (the "swap" operation). */
+  async updatePageId(
+    id: string,
+    pageId: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<ShareAlias> {
+    return dbOrTx(this.db, trx)
+      .updateTable('shareAliases')
+      .set({ pageId, updatedAt: new Date() })
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .returning(this.baseFields)
+      .executeTakeFirst();
+  }
+
+  async delete(
+    id: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<void> {
+    await dbOrTx(this.db, trx)
+      .deleteFrom('shareAliases')
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .execute();
+  }
+}

apps/server/src/database/types/db.d.ts

@@ -305,6 +305,16 @@ export interface Pages {
   ydoc: Buffer | null;
 }
 
+export interface ShareAliases {
+  alias: string;
+  createdAt: Generated<Timestamp>;
+  creatorId: string | null;
+  id: Generated<string>;
+  pageId: string | null;
+  updatedAt: Generated<Timestamp>;
+  workspaceId: string;
+}
+
 export interface Shares {
   createdAt: Generated<Timestamp>;
   creatorId: string | null;
@@ -674,6 +684,7 @@ export interface DB {
   pageVerifiers: PageVerifiers;
   pages: Pages;
   scimTokens: ScimTokens;
+  shareAliases: ShareAliases;
   shares: Shares;
   spaceMembers: SpaceMembers;
   spaces: Spaces;

apps/server/src/database/types/entity.types.ts

@@ -30,6 +30,7 @@ import {
   AuthProviders,
   AuthAccounts,
   Shares,
+  ShareAliases,
   Favorites,
   FileTasks,
   UserMfa as _UserMFA,
@@ -172,6 +173,11 @@ export type Share = Selectable<Shares>;
 export type InsertableShare = Insertable<Shares>;
 export type UpdatableShare = Updateable<Omit<Shares, 'id'>>;
 
+// Share alias (vanity /l/:alias pointer)
+export type ShareAlias = Selectable<ShareAliases>;
+export type InsertableShareAlias = Insertable<ShareAliases>;
+export type UpdatableShareAlias = Updateable<Omit<ShareAliases, 'id'>>;
+
 // Favorite
 export type Favorite = Selectable<Favorites>;
 export type InsertableFavorite = Insertable<Favorites>;

apps/server/src/main.ts

@@ -40,7 +40,14 @@ async function bootstrap() {
   app.useLogger(app.get(PinoLogger));
 
   app.setGlobalPrefix('api', {
-    exclude: ['robots.txt', 'share/:shareId/p/:pageSlug', 'mcp'],
+    exclude: [
+      'robots.txt',
+      'share/:shareId/p/:pageSlug',
+      // Vanity link resolver lives outside /api so /l/<alias> is a clean
+      // public URL that 302s to the canonical share page.
+      'l/:alias',
+      'mcp',
+    ],
   });
 
   const reflector = app.get(Reflector);