diff --git a/web/src/lib/musicbrainz.test.ts b/web/src/lib/musicbrainz.test.ts
new file mode 100644
index 0000000..bbe5bb4
--- /dev/null
+++ b/web/src/lib/musicbrainz.test.ts
@@ -0,0 +1,50 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { searchArtists, browseReleaseGroups, searchReleaseGroup } from "./musicbrainz";
+
+function jsonResponse(data: unknown) {
+  return Promise.resolve({ ok: true, status: 200, json: () => Promise.resolve(data) } as Response);
+}
+
+afterEach(() => vi.unstubAllGlobals());
+
+describe("musicbrainz module", () => {
+  it("searchArtists maps hits and sends a User-Agent", async () => {
+    const fetchMock = vi.fn(() =>
+      jsonResponse({ artists: [{ id: "a1", name: "John Mayer", disambiguation: "US singer" }] }),
+    );
+    vi.stubGlobal("fetch", fetchMock);
+    const hits = await searchArtists("john ma");
+    expect(hits).toEqual([{ mbid: "a1", name: "John Mayer", disambiguation: "US singer" }]);
+    const [, init] = fetchMock.mock.calls[0];
+    expect((init as RequestInit).headers).toMatchObject({ "User-Agent": expect.stringContaining("Lyra") });
+  });
+
+  it("browseReleaseGroups paginates until release-group-count is reached", async () => {
+    const page1 = { "release-group-count": 2, "release-groups": [{ id: "rg1", title: "A", "primary-type": "Album", "secondary-types": [], "first-release-date": "2001" }] };
+    const page2 = { "release-group-count": 2, "release-groups": [{ id: "rg2", title: "B", "primary-type": "EP", "secondary-types": ["Live"], "first-release-date": "" }] };
+    const fetchMock = vi.fn().mockReturnValueOnce(jsonResponse(page1)).mockReturnValueOnce(jsonResponse(page2));
+    vi.stubGlobal("fetch", fetchMock);
+    const rels = await browseReleaseGroups("a1");
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+    expect(rels).toEqual([
+      { rgMbid: "rg1", title: "A", primaryType: "Album", secondaryTypes: [], firstReleaseDate: "2001" },
+      { rgMbid: "rg2", title: "B", primaryType: "EP", secondaryTypes: ["Live"], firstReleaseDate: null },
+    ]);
+  });
+
+  it("throws on a non-2xx MusicBrainz response", async () => {
+    vi.stubGlobal("fetch", vi.fn(() => Promise.resolve({ ok: false, status: 503 } as Response)));
+    await expect(searchArtists("x")).rejects.toThrow(/503/);
+  });
+
+  it("searchReleaseGroup returns the top match with artist credit or null", async () => {
+    vi.stubGlobal("fetch", vi.fn(() => jsonResponse({ "release-groups": [
+      { id: "rg9", title: "Continuum", "primary-type": "Album", "secondary-types": [], "first-release-date": "2006-09-12", "artist-credit": [{ artist: { id: "a1", name: "John Mayer" } }] },
+    ] })));
+    const m = await searchReleaseGroup("John Mayer", "Continuum");
+    expect(m).toEqual({ rgMbid: "rg9", title: "Continuum", primaryType: "Album", secondaryTypes: [], firstReleaseDate: "2006-09-12", artistMbid: "a1", artistName: "John Mayer" });
+
+    vi.stubGlobal("fetch", vi.fn(() => jsonResponse({ "release-groups": [] })));
+    expect(await searchReleaseGroup("Nobody", "Nothing")).toBeNull();
+  });
+});
diff --git a/web/src/lib/musicbrainz.ts b/web/src/lib/musicbrainz.ts
new file mode 100644
index 0000000..d8f2f83
--- /dev/null
+++ b/web/src/lib/musicbrainz.ts
@@ -0,0 +1,65 @@
+const MB_BASE = "https://musicbrainz.org/ws/2";
+const USER_AGENT = "Lyra/0.1 ( https://git.jger.nl/Jonathan/Lyra )";
+
+export type ArtistHit = { mbid: string; name: string; disambiguation: string };
+export type ReleaseGroupInfo = {
+  rgMbid: string;
+  title: string;
+  primaryType: string | null;
+  secondaryTypes: string[];
+  firstReleaseDate: string | null;
+};
+export type ReleaseGroupMatch = ReleaseGroupInfo & { artistMbid: string; artistName: string };
+
+async function mbGet(path: string): Promise<any> {
+  const res = await fetch(`${MB_BASE}${path}`, {
+    headers: { "User-Agent": USER_AGENT, Accept: "application/json" },
+  });
+  if (!res.ok) throw new Error(`MusicBrainz request failed: ${res.status}`);
+  return res.json();
+}
+
+function toReleaseGroup(g: any): ReleaseGroupInfo {
+  return {
+    rgMbid: g.id,
+    title: g.title ?? "",
+    primaryType: g["primary-type"] ?? null,
+    secondaryTypes: g["secondary-types"] ?? [],
+    firstReleaseDate: g["first-release-date"] || null,
+  };
+}
+
+export async function searchArtists(query: string): Promise<ArtistHit[]> {
+  const data = await mbGet(`/artist?query=${encodeURIComponent(query)}&fmt=json&limit=8`);
+  return (data.artists ?? []).map((a: any) => ({
+    mbid: a.id,
+    name: a.name ?? "",
+    disambiguation: a.disambiguation ?? "",
+  }));
+}
+
+export async function browseReleaseGroups(artistMbid: string): Promise<ReleaseGroupInfo[]> {
+  const out: ReleaseGroupInfo[] = [];
+  let offset = 0;
+  for (;;) {
+    const data = await mbGet(
+      `/release-group?artist=${encodeURIComponent(artistMbid)}&fmt=json&limit=100&offset=${offset}`,
+    );
+    const groups: any[] = data["release-groups"] ?? [];
+    for (const g of groups) out.push(toReleaseGroup(g));
+    offset += groups.length;
+    const total = data["release-group-count"] ?? offset;
+    if (groups.length === 0 || offset >= total) break;
+  }
+  return out;
+}
+
+export async function searchReleaseGroup(artist: string, album: string): Promise<ReleaseGroupMatch | null> {
+  const query = `releasegroup:"${album}" AND artist:"${artist}"`;
+  const data = await mbGet(`/release-group?query=${encodeURIComponent(query)}&fmt=json&limit=5`);
+  const groups: any[] = data["release-groups"] ?? [];
+  if (groups.length === 0) return null;
+  const g = groups[0];
+  const credit = g["artist-credit"]?.[0]?.artist ?? {};
+  return { ...toReleaseGroup(g), artistMbid: credit.id ?? "", artistName: credit.name ?? artist };
+}
diff --git a/web/src/test/setup.ts b/web/src/test/setup.ts
index b83f3da..5d0b12e 100644
--- a/web/src/test/setup.ts
+++ b/web/src/test/setup.ts
@@ -2,8 +2,10 @@ import { beforeEach } from "vitest";
 import { prisma } from "@/lib/db";
 
 beforeEach(async () => {
-  // Job has a cascade FK to Request; delete Job first.
+  // Job cascades from Request; Request.monitoredReleaseId is SetNull. Delete children first.
   await prisma.job.deleteMany();
   await prisma.request.deleteMany();
+  await prisma.monitoredRelease.deleteMany();
+  await prisma.watchedArtist.deleteMany();
   await prisma.config.deleteMany();
 });