diff --git a/apps/api/package.json b/apps/api/package.json
index 5858c13..0a3a520 100644
--- a/apps/api/package.json
+++ b/apps/api/package.json
@@ -12,7 +12,8 @@
     "test": "vitest run --passWithNoTests",
     "db:migrate:dev": "prisma migrate dev",
     "db:seed": "tsx prisma/seed.ts",
-    "fixtures:regenerate": "tsx prisma/fixtures/regenerate.ts"
+    "fixtures:regenerate": "tsx prisma/fixtures/regenerate.ts",
+    "search:reindex": "tsx src/search/reindex.cli.ts"
   },
   "dependencies": {
     "@dorfteich/shared": "workspace:*",
diff --git a/apps/api/prisma/migrations/20260709111040_search_vector/migration.sql b/apps/api/prisma/migrations/20260709111040_search_vector/migration.sql
new file mode 100644
index 0000000..97f0935
--- /dev/null
+++ b/apps/api/prisma/migrations/20260709111040_search_vector/migration.sql
@@ -0,0 +1,8 @@
+-- AlterTable
+ALTER TABLE "page_content_cache" ADD COLUMN     "search_vector" tsvector;
+
+-- GIN index for the weighted full-text search vector (issue #49, ADR 0010).
+-- The vector itself is maintained in application code (SearchProvider /
+-- collab persistence); this index only speeds up matching in production.
+CREATE INDEX "page_content_cache_search_vector_idx"
+  ON "page_content_cache" USING GIN ("search_vector");
diff --git a/apps/api/prisma/schema.prisma b/apps/api/prisma/schema.prisma
index 173335e..e800ffd 100644
--- a/apps/api/prisma/schema.prisma
+++ b/apps/api/prisma/schema.prisma
@@ -202,6 +202,11 @@ model PageContentCache {
   html      String
   outline   Json
   updatedAt DateTime @updatedAt @map("updated_at")
+  /// Weighted full-text search vector (title A, labels B, body C; issue #49,
+  /// ADR 0010). Maintained by the SearchProvider and the collab persistence
+  /// hook (both write it with the same weighting). The GIN index is added in
+  /// the migration (raw SQL — Prisma cannot index an Unsupported column).
+  searchVector Unsupported("tsvector")? @map("search_vector")
 
   page Page @relation(fields: [pageId], references: [id], onDelete: Cascade)
 
diff --git a/apps/api/src/app.module.ts b/apps/api/src/app.module.ts
index dcbb715..d96ee15 100644
--- a/apps/api/src/app.module.ts
+++ b/apps/api/src/app.module.ts
@@ -17,6 +17,7 @@ import { PagesModule } from './pages/pages.module';
 import { PondsModule } from './ponds/ponds.module';
 import { PrismaModule } from './prisma/prisma.module';
 import { RateLimitModule } from './rate-limit/rate-limit.module';
+import { SearchModule } from './search/search.module';
 import { SettingsModule } from './settings/settings.module';
 import { TrashModule } from './trash/trash.module';
 import { UsersModule } from './users/users.module';
@@ -38,6 +39,7 @@ import { VersionsModule } from './versions/versions.module';
     VersionsModule,
     LabelsModule,
     LinksModule,
+    SearchModule,
     AuthModule,
     AdminModule,
     LoggerModule.forRootAsync({
diff --git a/apps/api/src/labels/labels.module.ts b/apps/api/src/labels/labels.module.ts
index e5e8ca9..556f352 100644
--- a/apps/api/src/labels/labels.module.ts
+++ b/apps/api/src/labels/labels.module.ts
@@ -1,12 +1,13 @@
 import { Module } from '@nestjs/common';
 
 import { PondsModule } from '../ponds/ponds.module';
+import { SearchModule } from '../search/search.module';
 
 import { LabelsController } from './labels.controller';
 import { LabelsService } from './labels.service';
 
 @Module({
-  imports: [PondsModule],
+  imports: [PondsModule, SearchModule],
   controllers: [LabelsController],
   providers: [LabelsService],
   exports: [LabelsService],
diff --git a/apps/api/src/labels/labels.service.ts b/apps/api/src/labels/labels.service.ts
index 899982e..8f24814 100644
--- a/apps/api/src/labels/labels.service.ts
+++ b/apps/api/src/labels/labels.service.ts
@@ -22,6 +22,7 @@ import { PinoLogger } from 'nestjs-pino';
 
 import { InterimAccessService } from '../ponds/interim-access.service';
 import { PrismaService } from '../prisma/prisma.service';
+import { SearchProvider } from '../search/search.provider';
 
 /** Transaction client type, so the locked helpers can read and write atomically. */
 type Tx = Prisma.TransactionClient;
@@ -45,10 +46,24 @@ export class LabelsService {
     private readonly prisma: PrismaService,
     private readonly access: InterimAccessService,
     private readonly logger: PinoLogger,
+    private readonly search: SearchProvider,
   ) {
     this.logger.setContext(LabelsService.name);
   }
 
+  /** Re-index every page that carries any of the given labels (issue #49):
+   * label names are the weight-B search field, so an assignment/rename/delete
+   * changes those pages' search entries. */
+  private async reindexPagesWithLabels(labelIds: string[]): Promise<void> {
+    if (labelIds.length === 0) return;
+    const rows = await this.prisma.pageLabel.findMany({
+      where: { labelId: { in: labelIds } },
+      select: { pageId: true },
+      distinct: ['pageId'],
+    });
+    for (const row of rows) await this.search.indexPage(row.pageId);
+  }
+
   viewOf(label: Label): LabelView {
     return {
       id: label.id,
@@ -167,6 +182,10 @@ export class LabelsService {
         data: { name: input.name, color: input.color },
       });
     });
+    // A renamed label changes the search entry of every page carrying it (#49).
+    if (input.name !== undefined && input.name !== existing.name) {
+      await this.reindexPagesWithLabels([labelId]);
+    }
     return this.viewOf(label);
   }
 
@@ -215,20 +234,27 @@ export class LabelsService {
     const existing = await this.requireModifiableLabel(user, labelId);
     const pondId = existing.pondId;
 
-    await this.withPondLock(pondId, async (tx) => {
+    const affectedPageIds = await this.withPondLock(pondId, async (tx) => {
       const labels = await this.allPondLabels(tx, pondId);
       const subtree = [...collectSubtreeIds(labels, labelId)];
-      const assigned = await tx.pageLabel.count({ where: { labelId: { in: subtree } } });
-      if (assigned > 0 && !force) {
+      const assignments = await tx.pageLabel.findMany({
+        where: { labelId: { in: subtree } },
+        select: { pageId: true },
+        distinct: ['pageId'],
+      });
+      if (assignments.length > 0 && !force) {
         throw new ConflictException({
           code: 'label_has_pages',
-          details: { count: [String(assigned)] },
+          details: { count: [String(assignments.length)] },
         });
       }
       // Deleting the root cascades to the subtree and to all page assignments.
       await tx.label.delete({ where: { id: labelId } });
+      return assignments.map((a) => a.pageId);
     });
 
+    // Those pages lost a label → their search entries change (#49).
+    for (const pageId of affectedPageIds) await this.search.indexPage(pageId);
     this.logger.info({ labelId, pondId, userId: user.id, force }, 'audit: label deleted');
   }
 
@@ -273,6 +299,7 @@ export class LabelsService {
       create: { pageId, labelId },
       update: {},
     });
+    await this.search.indexPage(pageId); // labels are a search field (#49)
     return this.pageLabels(user, pageId);
   }
 
@@ -280,5 +307,6 @@ export class LabelsService {
   async unassign(user: User, pageId: string, labelId: string): Promise<void> {
     await this.requireModifiablePage(user, pageId);
     await this.prisma.pageLabel.deleteMany({ where: { pageId, labelId } });
+    await this.search.indexPage(pageId); // labels are a search field (#49)
   }
 }
diff --git a/apps/api/src/pages/pages.module.ts b/apps/api/src/pages/pages.module.ts
index 7e6544b..a954701 100644
--- a/apps/api/src/pages/pages.module.ts
+++ b/apps/api/src/pages/pages.module.ts
@@ -1,12 +1,13 @@
 import { Module } from '@nestjs/common';
 
 import { PondsModule } from '../ponds/ponds.module';
+import { SearchModule } from '../search/search.module';
 
 import { PagesController } from './pages.controller';
 import { PagesService } from './pages.service';
 
 @Module({
-  imports: [PondsModule],
+  imports: [PondsModule, SearchModule],
   controllers: [PagesController],
   providers: [PagesService],
   exports: [PagesService],
diff --git a/apps/api/src/pages/pages.service.ts b/apps/api/src/pages/pages.service.ts
index 06d1569..6603775 100644
--- a/apps/api/src/pages/pages.service.ts
+++ b/apps/api/src/pages/pages.service.ts
@@ -19,6 +19,7 @@ import { PinoLogger } from 'nestjs-pino';
 import { AppConfig } from '../config/app-config.service';
 import { InterimAccessService } from '../ponds/interim-access.service';
 import { PrismaService } from '../prisma/prisma.service';
+import { SearchProvider } from '../search/search.provider';
 import { evenlySpacedKeys, nextKeyOrRebalance } from './sort-key';
 import { deriveContent, DerivedPageContent, emptyPageState } from './yjs-content';
 
@@ -45,6 +46,7 @@ export class PagesService {
     private readonly access: InterimAccessService,
     private readonly logger: PinoLogger,
     private readonly config: AppConfig,
+    private readonly search: SearchProvider,
   ) {
     this.logger.setContext(PagesService.name);
   }
@@ -157,6 +159,8 @@ export class PagesService {
     });
     // A new page may satisfy phantom wikilinks that referenced its slug (#47).
     await this.resolvePhantomLinks(pond.id, slug, page.id);
+    // Index the (empty) page so a title-only match is findable immediately (#49).
+    await this.search.indexPage(page.id);
     this.logger.info({ pageId: page.id, pondId: pond.id, userId: user.id }, 'audit: page created');
     return this.viewOf(page);
   }
@@ -247,6 +251,10 @@ export class PagesService {
     });
     // Renaming to a slug pages already link to resolves those phantom links (#47).
     if (slug !== page.slug) await this.resolvePhantomLinks(page.pondId, slug, page.id);
+    // A changed title changes the (weighted) search entry (#49).
+    if (input.title !== undefined && input.title !== page.title) {
+      await this.search.indexPage(page.id);
+    }
     return this.viewOf(updated);
   }
 
diff --git a/apps/api/src/search/postgres-search.provider.ts b/apps/api/src/search/postgres-search.provider.ts
new file mode 100644
index 0000000..3a7820c
--- /dev/null
+++ b/apps/api/src/search/postgres-search.provider.ts
@@ -0,0 +1,140 @@
+import { Injectable } from '@nestjs/common';
+import {
+  SEARCH_HIGHLIGHT_END,
+  SEARCH_HIGHLIGHT_START,
+  SEARCH_RESULT_LIMIT,
+  SearchQuery,
+  SearchResultView,
+  normalizeForSearch,
+} from '@dorfteich/shared';
+import { Prisma, User } from '@prisma/client';
+
+import { PrismaService } from '../prisma/prisma.service';
+import { SearchProvider } from './search.provider';
+
+/** ts_headline options — one fragment, matches wrapped in the shared sentinels. */
+const HEADLINE_OPTIONS =
+  `StartSel=${SEARCH_HIGHLIGHT_START}, StopSel=${SEARCH_HIGHLIGHT_END}, ` +
+  'MaxFragments=1, MaxWords=30, MinWords=8, ShortWord=0';
+
+/** Raw title/labels/body for one page, before normalization. */
+interface IndexSource {
+  title: string;
+  labels: string | null;
+  plain_text: string | null;
+}
+
+interface SearchRow {
+  pageId: string;
+  title: string;
+  slug: string;
+  pondId: string;
+  pondSlug: string;
+  pondName: string;
+  labelIds: string[];
+  snippet: string;
+}
+
+/**
+ * PostgreSQL full-text search (ADR 0010, issue #49). The weighted `tsvector`
+ * (title A, labels B, body C) is stored on `page_content_cache.search_vector`
+ * and maintained here (and by the collab persistence hook on content changes);
+ * both fold text through {@link normalizeForSearch} before `to_tsvector` so
+ * matching is diacritic-insensitive without the `unaccent` extension. Queries
+ * are folded the same way; results are filtered to the ponds the user may read.
+ */
+@Injectable()
+export class PostgresSearchProvider extends SearchProvider {
+  constructor(private readonly prisma: PrismaService) {
+    super();
+  }
+
+  async indexPage(pageId: string): Promise<void> {
+    const rows = await this.prisma.$queryRaw<IndexSource[]>`
+      SELECT p.title,
+             c.plain_text,
+             (SELECT string_agg(l.name, ' ')
+                FROM page_labels pl JOIN labels l ON l.id = pl.label_id
+               WHERE pl.page_id = p.id) AS labels
+        FROM pages p
+        LEFT JOIN page_content_cache c ON c.page_id = p.id
+       WHERE p.id = ${pageId}`;
+    const source = rows[0];
+    if (!source) return;
+    await this.writeVector(pageId, source);
+  }
+
+  async removePage(pageId: string): Promise<void> {
+    await this.prisma
+      .$executeRaw`UPDATE page_content_cache SET search_vector = NULL WHERE page_id = ${pageId}`;
+  }
+
+  async reindexAll(): Promise<number> {
+    const sources = await this.prisma.$queryRaw<(IndexSource & { page_id: string })[]>`
+      SELECT p.id AS page_id, p.title, c.plain_text,
+             (SELECT string_agg(l.name, ' ')
+                FROM page_labels pl JOIN labels l ON l.id = pl.label_id
+               WHERE pl.page_id = p.id) AS labels
+        FROM page_content_cache c
+        JOIN pages p ON p.id = c.page_id`;
+    for (const source of sources) await this.writeVector(source.page_id, source);
+    return sources.length;
+  }
+
+  /** Writes the weighted, normalized vector for one page (shared by index/reindex). */
+  private async writeVector(pageId: string, source: IndexSource): Promise<void> {
+    const title = normalizeForSearch(source.title ?? '');
+    const labels = normalizeForSearch(source.labels ?? '');
+    const body = normalizeForSearch(source.plain_text ?? '');
+    await this.prisma.$executeRaw`
+      UPDATE page_content_cache SET search_vector =
+          setweight(to_tsvector('simple', ${title}), 'A')
+        || setweight(to_tsvector('simple', ${labels}), 'B')
+        || setweight(to_tsvector('simple', ${body}), 'C')
+      WHERE page_id = ${pageId}`;
+  }
+
+  async search(query: SearchQuery, user: User): Promise<SearchResultView[]> {
+    const normalized = normalizeForSearch(query.q);
+    // A phrase that folds to nothing (e.g. only punctuation) matches nothing.
+    if (normalized.trim() === '') return [];
+
+    const scope = query.pondId ? Prisma.sql`AND p.pond_id = ${query.pondId}` : Prisma.empty;
+    const labelFilter =
+      query.labels && query.labels.length > 0
+        ? Prisma.sql`AND EXISTS (SELECT 1 FROM page_labels pl
+                                  WHERE pl.page_id = p.id AND pl.label_id = ANY(${query.labels}))`
+        : Prisma.empty;
+
+    const rows = await this.prisma.$queryRaw<SearchRow[]>(Prisma.sql`
+      SELECT p.id AS "pageId", p.title, p.slug, p.pond_id AS "pondId",
+             po.slug AS "pondSlug", po.name AS "pondName",
+             COALESCE(
+               ARRAY(SELECT pl.label_id FROM page_labels pl WHERE pl.page_id = p.id),
+               '{}'
+             ) AS "labelIds",
+             ts_headline('simple', c.plain_text,
+               websearch_to_tsquery('simple', ${query.q}), ${HEADLINE_OPTIONS}) AS snippet
+        FROM page_content_cache c
+        JOIN pages p ON p.id = c.page_id AND p.deleted_at IS NULL
+        JOIN ponds po ON po.id = p.pond_id AND po.deleted_at IS NULL,
+             websearch_to_tsquery('simple', ${normalized}) q
+       WHERE c.search_vector @@ q
+         AND (${user.isSiteAdmin}::boolean OR po.owner_id = ${user.id})
+         ${scope}
+         ${labelFilter}
+       ORDER BY ts_rank(c.search_vector, q) DESC, p.updated_at DESC
+       LIMIT ${SEARCH_RESULT_LIMIT}`);
+
+    return rows.map((row) => ({
+      pageId: row.pageId,
+      title: row.title,
+      slug: row.slug,
+      pondId: row.pondId,
+      pondSlug: row.pondSlug,
+      pondName: row.pondName,
+      labelIds: row.labelIds,
+      snippet: row.snippet,
+    }));
+  }
+}
diff --git a/apps/api/src/search/reindex.cli.ts b/apps/api/src/search/reindex.cli.ts
new file mode 100644
index 0000000..b9fbc2b
--- /dev/null
+++ b/apps/api/src/search/reindex.cli.ts
@@ -0,0 +1,27 @@
+import { PrismaService } from '../prisma/prisma.service';
+import { PostgresSearchProvider } from './postgres-search.provider';
+
+/**
+ * `search:reindex` CLI (ADR 0010, issue #49): rebuilds the whole search index
+ * from `page_content_cache`, idempotently — safe to run after a schema change,
+ * a reseed, or a provider swap. It instantiates the PostgreSQL provider
+ * directly (no Nest DI): the CLI is run with `tsx`, whose esbuild transform does
+ * not emit the decorator metadata Nest injection relies on. The provider itself
+ * is still the one bound in the app (proven by the DI test) — only the CLI's
+ * wiring is manual.
+ */
+async function main(): Promise<void> {
+  const prisma = new PrismaService();
+  const provider = new PostgresSearchProvider(prisma);
+  try {
+    const count = await provider.reindexAll();
+    console.log(`search:reindex — indexed ${count} page(s)`);
+  } finally {
+    await prisma.$disconnect();
+  }
+}
+
+void main().catch((error) => {
+  console.error('search:reindex failed:', error);
+  process.exitCode = 1;
+});
diff --git a/apps/api/src/search/search.controller.ts b/apps/api/src/search/search.controller.ts
new file mode 100644
index 0000000..01712c6
--- /dev/null
+++ b/apps/api/src/search/search.controller.ts
@@ -0,0 +1,33 @@
+import { BadRequestException, Controller, Get, Query, Req } from '@nestjs/common';
+import { SearchQuery, SearchResultView, searchQuerySchema } from '@dorfteich/shared';
+
+import { AuthedRequest } from '../auth/auth.guard';
+import { SearchProvider } from './search.provider';
+
+/** Full-text search (issue #49, ADR 0010). */
+@Controller()
+export class SearchController {
+  constructor(private readonly search: SearchProvider) {}
+
+  /**
+   * `GET /search?q=…&pondId=…&labels=a,b` — ranked, permission-filtered hits.
+   * `labels` is a comma-separated list; scope defaults to all readable ponds.
+   */
+  @Get('search')
+  async query(
+    @Query('q') q: string,
+    @Query('pondId') pondId: string | undefined,
+    @Query('labels') labels: string | undefined,
+    @Req() request: AuthedRequest,
+  ): Promise<SearchResultView[]> {
+    const parsed = searchQuerySchema.safeParse({
+      q,
+      pondId: pondId || undefined,
+      labels: labels ? labels.split(',').filter(Boolean) : undefined,
+    } satisfies Record<string, unknown>);
+    if (!parsed.success) {
+      throw new BadRequestException({ code: 'bad_request' });
+    }
+    return this.search.search(parsed.data as SearchQuery, request.user!);
+  }
+}
diff --git a/apps/api/src/search/search.module.ts b/apps/api/src/search/search.module.ts
new file mode 100644
index 0000000..78f741c
--- /dev/null
+++ b/apps/api/src/search/search.module.ts
@@ -0,0 +1,17 @@
+import { Module } from '@nestjs/common';
+
+import { SearchController } from './search.controller';
+import { PostgresSearchProvider } from './postgres-search.provider';
+import { SearchProvider } from './search.provider';
+
+/**
+ * Search module (ADR 0010). Binds the `SearchProvider` token to the PostgreSQL
+ * implementation; swapping in an external engine is a one-line provider change.
+ * Exports the provider so pages/labels can re-index on title/label changes.
+ */
+@Module({
+  controllers: [SearchController],
+  providers: [{ provide: SearchProvider, useClass: PostgresSearchProvider }],
+  exports: [SearchProvider],
+})
+export class SearchModule {}
diff --git a/apps/api/src/search/search.provider.test.ts b/apps/api/src/search/search.provider.test.ts
new file mode 100644
index 0000000..6bfe910
--- /dev/null
+++ b/apps/api/src/search/search.provider.test.ts
@@ -0,0 +1,52 @@
+import { SearchResultView } from '@dorfteich/shared';
+import { Test } from '@nestjs/testing';
+import { User } from '@prisma/client';
+import { describe, expect, it, vi } from 'vitest';
+
+import { AuthedRequest } from '../auth/auth.guard';
+import { SearchController } from './search.controller';
+import { SearchProvider } from './search.provider';
+
+/**
+ * Proves the `SearchProvider` seam (ADR 0010 / issue #49): the controller
+ * depends on the abstract token, so a fake implementation can replace the
+ * PostgreSQL binding entirely in a test — which is exactly how an external
+ * engine would be swapped in.
+ */
+describe('SearchProvider DI seam (issue #49)', () => {
+  it('lets a fake provider replace the real binding', async () => {
+    const hit: SearchResultView = {
+      pageId: 'p1',
+      title: 'Hit',
+      slug: 'hit',
+      pondId: 'pond1',
+      pondSlug: 'pond',
+      pondName: 'Pond',
+      labelIds: [],
+      snippet: 'a snippet',
+    };
+    const fake: SearchProvider = {
+      indexPage: vi.fn(),
+      removePage: vi.fn(),
+      reindexAll: vi.fn(),
+      search: vi.fn().mockResolvedValue([hit]),
+    };
+
+    const moduleRef = await Test.createTestingModule({
+      controllers: [SearchController],
+      providers: [{ provide: SearchProvider, useValue: fake }],
+    }).compile();
+
+    const controller = moduleRef.get(SearchController);
+    const user = { id: 'u1', isSiteAdmin: false } as User;
+    const result = await controller.query('hello', 'pond1', 'a,b', {
+      user,
+    } as AuthedRequest);
+
+    expect(result).toEqual([hit]);
+    expect(fake.search).toHaveBeenCalledWith(
+      { q: 'hello', pondId: 'pond1', labels: ['a', 'b'] },
+      user,
+    );
+  });
+});
diff --git a/apps/api/src/search/search.provider.ts b/apps/api/src/search/search.provider.ts
new file mode 100644
index 0000000..390406f
--- /dev/null
+++ b/apps/api/src/search/search.provider.ts
@@ -0,0 +1,20 @@
+import { SearchQuery, SearchResultView } from '@dorfteich/shared';
+import { User } from '@prisma/client';
+
+/**
+ * Search behind an interface (ADR 0010, issue #49) so an external engine can
+ * replace the PostgreSQL binding without touching call sites. Bound via DI as an
+ * abstract-class token — a fake implementation can be provided in tests, which
+ * is what proves the seam. `search` receives the requesting user so results are
+ * permission-filtered; scope (pond, labels) lives in the query.
+ */
+export abstract class SearchProvider {
+  /** (Re)compute the search entry for one page from its current content. */
+  abstract indexPage(pageId: string): Promise<void>;
+  /** Drop a page from the index (its cache row is also removed on purge). */
+  abstract removePage(pageId: string): Promise<void>;
+  /** Ranked, permission-filtered results for `user`. */
+  abstract search(query: SearchQuery, user: User): Promise<SearchResultView[]>;
+  /** Rebuild the whole index from `page_content_cache`; returns rows indexed. */
+  abstract reindexAll(): Promise<number>;
+}
diff --git a/apps/api/src/search/search.service.db.test.ts b/apps/api/src/search/search.service.db.test.ts
new file mode 100644
index 0000000..71a3c9d
--- /dev/null
+++ b/apps/api/src/search/search.service.db.test.ts
@@ -0,0 +1,116 @@
+import { randomUUID } from 'node:crypto';
+
+import { SEARCH_HIGHLIGHT_START } from '@dorfteich/shared';
+import { INestApplication } from '@nestjs/common';
+import { PrismaClient, User } from '@prisma/client';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import * as Y from 'yjs';
+
+import { createTestApp } from '../testing/test-app';
+import { createTestPrisma, hasTestDb, uniqueSuffix } from '../testing/test-db';
+import { SearchProvider } from './search.provider';
+
+describe.skipIf(!hasTestDb)('PostgresSearchProvider (db, issue #49)', () => {
+  let app: INestApplication;
+  let prisma: PrismaClient;
+  let search: SearchProvider;
+  const suffix = uniqueSuffix();
+  const term = `zeb${suffix}`; // a term unique to this run
+  let owner: User;
+  let outsider: User;
+  let pondId: string;
+  const pageIds: string[] = [];
+
+  /** Creates a page with an indexed content cache, then indexes it. */
+  async function makePage(title: string, plainText: string): Promise<string> {
+    const id = randomUUID();
+    await prisma.page.create({
+      data: {
+        id,
+        pondId,
+        title,
+        slug: `p-${id.slice(0, 8)}`,
+        ydocState: new Uint8Array(Y.encodeStateAsUpdate(new Y.Doc())),
+        sortKey: `a${pageIds.length}`,
+        createdBy: owner.id,
+        contentCache: { create: { plainText, markdown: plainText, html: plainText, outline: [] } },
+      },
+    });
+    pageIds.push(id);
+    await search.indexPage(id);
+    return id;
+  }
+
+  beforeAll(async () => {
+    prisma = createTestPrisma();
+    app = await createTestApp();
+    search = app.get(SearchProvider);
+
+    owner = await prisma.user.create({
+      data: {
+        username: `srch-owner-${suffix}`,
+        email: `srch-owner-${suffix}@example.test`,
+        displayName: 'Search Owner',
+      },
+    });
+    outsider = await prisma.user.create({
+      data: {
+        username: `srch-out-${suffix}`,
+        email: `srch-out-${suffix}@example.test`,
+        displayName: 'Search Outsider',
+      },
+    });
+    const pond = await prisma.pond.create({
+      data: {
+        slug: `srch-pond-${suffix}`,
+        name: 'Search Pond',
+        type: 'PERSONAL',
+        ownerId: owner.id,
+      },
+    });
+    pondId = pond.id;
+  });
+
+  afterAll(async () => {
+    await prisma.page.deleteMany({ where: { pondId } });
+    await prisma.pond.deleteMany({ where: { id: pondId } });
+    await prisma.user.deleteMany({ where: { id: { in: [owner.id, outsider.id] } } });
+    await prisma.$disconnect();
+    await app.close();
+  });
+
+  it('ranks a title match above a body match', async () => {
+    const titleHit = await makePage(`${term} in the title`, 'unrelated body text');
+    await makePage('unrelated title', `a long story that mentions ${term} in the body only`);
+
+    const results = await search.search({ q: term }, owner);
+    expect(results.length).toBeGreaterThanOrEqual(2);
+    // Weight A (title) outranks weight C (body).
+    expect(results[0]!.pageId).toBe(titleHit);
+  });
+
+  it('highlights the match in the snippet', async () => {
+    const results = await search.search({ q: term }, owner);
+    const bodyHit = results.find((r) => r.snippet.includes(SEARCH_HIGHLIGHT_START));
+    expect(bodyHit).toBeDefined();
+  });
+
+  it('matches diacritics-insensitively (Baume finds Bäume)', async () => {
+    const page = await makePage('Wald', `viele Bäume-${suffix} im Wald`);
+    const results = await search.search({ q: `Baume-${suffix}` }, owner);
+    expect(results.map((r) => r.pageId)).toContain(page);
+  });
+
+  it('never returns pages the requester may not read', async () => {
+    const results = await search.search({ q: term }, outsider);
+    expect(results).toEqual([]);
+  });
+
+  it('reindexAll rebuilds from the cache and is idempotent', async () => {
+    const before = await search.search({ q: term }, owner);
+    await search.reindexAll();
+    await search.reindexAll();
+    const after = await search.search({ q: term }, owner);
+    expect(after.map((r) => r.pageId).sort()).toEqual(before.map((r) => r.pageId).sort());
+  });
+});
diff --git a/apps/collab/src/persistence.ts b/apps/collab/src/persistence.ts
index 159e09a..b220683 100644
--- a/apps/collab/src/persistence.ts
+++ b/apps/collab/src/persistence.ts
@@ -1,4 +1,4 @@
-import { MAX_PAGE_DOCUMENT_BYTES } from '@dorfteich/shared';
+import { MAX_PAGE_DOCUMENT_BYTES, normalizeForSearch } from '@dorfteich/shared';
 import type { Pool } from 'pg';
 import * as Y from 'yjs';
 
@@ -101,8 +101,8 @@ export class PostgresPagePersistence implements PagePersistence {
 
       // Lock the page row for the duration of the flush: this serialises seq
       // allocation and guards against storing to a page trashed mid-session.
-      const page = await client.query<{ pond_id: string }>(
-        'SELECT pond_id FROM pages WHERE id = $1 AND deleted_at IS NULL FOR UPDATE',
+      const page = await client.query<{ pond_id: string; title: string }>(
+        'SELECT pond_id, title FROM pages WHERE id = $1 AND deleted_at IS NULL FOR UPDATE',
         [pageId],
       );
       const pageMeta = page.rows[0];
@@ -165,6 +165,29 @@ export class PostgresPagePersistence implements PagePersistence {
         );
       }
 
+      // Maintain the weighted full-text search vector (issue #49) in the same
+      // transaction as the cache — the same weighting the api's SearchProvider
+      // uses, folded through normalizeForSearch for diacritic-insensitive match.
+      const labelRow = await client.query<{ names: string | null }>(
+        `SELECT string_agg(l.name, ' ') AS names
+           FROM page_labels pl JOIN labels l ON l.id = pl.label_id
+          WHERE pl.page_id = $1`,
+        [pageId],
+      );
+      await client.query(
+        `UPDATE page_content_cache SET search_vector =
+             setweight(to_tsvector('simple', $2), 'A')
+           || setweight(to_tsvector('simple', $3), 'B')
+           || setweight(to_tsvector('simple', $4), 'C')
+         WHERE page_id = $1`,
+        [
+          pageId,
+          normalizeForSearch(pageMeta.title ?? ''),
+          normalizeForSearch(labelRow.rows[0]?.names ?? ''),
+          normalizeForSearch(derived.plainText),
+        ],
+      );
+
       // Rewrite this page's outgoing wikilink index (issue #47): replace all its
       // rows with one per distinct target slug, resolved to a page in the same
       // pond (null `to_page_id` = phantom, target does not exist yet).
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 2a63c10..7a96d22 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -9,6 +9,7 @@ export * from './i18n-tools';
 export * from './labels';
 export * from './links';
 export * from './pages';
+export * from './search';
 export * from './ponds';
 export * from './quotas';
 export * from './text-diff';
diff --git a/packages/shared/src/search.test.ts b/packages/shared/src/search.test.ts
new file mode 100644
index 0000000..cf5fdcd
--- /dev/null
+++ b/packages/shared/src/search.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+
+import { normalizeForSearch, searchQuerySchema } from './search';
+
+describe('normalizeForSearch (issue #49)', () => {
+  it('strips diacritics and lowercases so accents do not matter', () => {
+    expect(normalizeForSearch('Bäume')).toBe('baume');
+    expect(normalizeForSearch('Café')).toBe('cafe');
+    expect(normalizeForSearch('Zürich Über')).toBe('zurich uber');
+  });
+
+  it('leaves ascii text lowercased and otherwise intact', () => {
+    expect(normalizeForSearch('Zebra Alpha')).toBe('zebra alpha');
+  });
+});
+
+describe('searchQuerySchema (issue #49)', () => {
+  it('requires a non-empty query and parses optional scope', () => {
+    expect(searchQuerySchema.safeParse({ q: '' }).success).toBe(false);
+    const ok = searchQuerySchema.parse({ q: '  hi ', pondId: 'p1', labels: ['a', 'b'] });
+    expect(ok).toEqual({ q: 'hi', pondId: 'p1', labels: ['a', 'b'] });
+  });
+});
diff --git a/packages/shared/src/search.ts b/packages/shared/src/search.ts
new file mode 100644
index 0000000..60845ed
--- /dev/null
+++ b/packages/shared/src/search.ts
@@ -0,0 +1,52 @@
+import { z } from 'zod';
+
+/**
+ * Search schemas and views (issue #49/#50, ADR 0010). Full-text search runs on
+ * PostgreSQL behind the `SearchProvider` interface. Diacritic-insensitive
+ * matching ('Baume' finds 'Bäume') is achieved by normalizing both the indexed
+ * text and the query in application code — so no Postgres `unaccent` extension
+ * is required (which keeps the schema-pushed test databases working).
+ */
+
+// Combining diacritical marks (U+0300–U+036F), removed after NFKD decomposition.
+const COMBINING_MARKS = /[̀-ͯ]/g;
+
+/**
+ * Fold a string for search: strip diacritics (NFKD + drop combining marks) and
+ * lowercase, leaving tokenization to Postgres `to_tsvector('simple', …)`. Used
+ * for BOTH the stored search vector and the query, so they always agree.
+ */
+export function normalizeForSearch(text: string): string {
+  return text.normalize('NFKD').replace(COMBINING_MARKS, '').toLowerCase();
+}
+
+/** Sentinels wrapping a matched span in a result snippet (`ts_headline`), split
+ * by the UI to render highlights without trusting HTML from the content.
+ * Private-use codepoints that never occur in page text. */
+export const SEARCH_HIGHLIGHT_START = String.fromCodePoint(0xe000);
+export const SEARCH_HIGHLIGHT_END = String.fromCodePoint(0xe001);
+
+/** How many results one search returns (v1, ADR 0010 target scale). */
+export const SEARCH_RESULT_LIMIT = 30;
+
+export const searchQuerySchema = z.object({
+  q: z.string().trim().min(1, 'validation.required').max(200, 'validation.tooLong'),
+  /** Restrict to one pond; omitted = all ponds the user may read. */
+  pondId: z.string().min(1).optional(),
+  /** Restrict to pages carrying any of these label ids. */
+  labels: z.array(z.string().min(1)).optional(),
+});
+export type SearchQuery = z.infer<typeof searchQuerySchema>;
+
+/** One hit: the page, its pond, its labels, and a highlighted snippet. */
+export interface SearchResultView {
+  pageId: string;
+  title: string;
+  slug: string;
+  pondId: string;
+  pondSlug: string;
+  pondName: string;
+  labelIds: string[];
+  /** Snippet with matches wrapped in the highlight sentinels above. */
+  snippet: string;
+}