diff --git a/src/db/seed.js b/src/db/seed.js
index e546fe2..5643a5e 100644
--- a/src/db/seed.js
+++ b/src/db/seed.js
@@ -14,6 +14,7 @@ export function seed() {
       body: `${title} body`,
       tags: i % 2 === 0 ? ['home'] : ['work'],
       createdAt: Date.UTC(2026, 0, 1 + i),
+      archived: false,
     });
   });
   insert('tags', { id: 't1', name: 'home' });
diff --git a/src/routes/notes.js b/src/routes/notes.js
index 8248dc1..2e9757b 100644
--- a/src/routes/notes.js
+++ b/src/routes/notes.js
@@ -1,8 +1,11 @@
-import { createNote, deleteNote, getNote, listNotes, updateNote } from '../services/notes.js';
+import { createNote, deleteNote, getNote, listNotes, setArchived, updateNote } from '../services/notes.js';
 import { noteSummary } from '../utils/format.js';
 
 export const notesRoutes = {
-  'GET /notes': (req) => ({ status: 200, body: listNotes(req.user.id).map(noteSummary) }),
+  'GET /notes': (req) => ({
+    status: 200,
+    body: listNotes(req.user.id, { archived: String(req.query?.archived) === 'true' }).map(noteSummary),
+  }),
   'GET /notes/:id': (req) => {
     const note = getNote(req.user.id, req.params.id);
     return note ? { status: 200, body: note } : { status: 404, body: { error: 'not found' } };
@@ -12,5 +15,13 @@ export const notesRoutes = {
     const note = updateNote(req.user.id, req.params.id, req.body ?? {});
     return note ? { status: 200, body: note } : { status: 404, body: { error: 'not found' } };
   },
+  'POST /notes/:id/archive': (req) => {
+    const note = setArchived(req.user.id, req.params.id, true);
+    return note ? { status: 200, body: note } : { status: 404, body: { error: 'not found' } };
+  },
+  'POST /notes/:id/unarchive': (req) => {
+    const note = setArchived(req.user.id, req.params.id, false);
+    return note ? { status: 200, body: note } : { status: 404, body: { error: 'not found' } };
+  },
   'DELETE /notes/:id': (req) => (deleteNote(req.user.id, req.params.id) ? { status: 204 } : { status: 404, body: { error: 'not found' } }),
 };
diff --git a/src/services/notes.js b/src/services/notes.js
index 653af57..6ffed96 100644
--- a/src/services/notes.js
+++ b/src/services/notes.js
@@ -4,16 +4,26 @@ import { requireString, optionalTags } from '../utils/validate.js';
 import { invalidate } from './cache.js';
 import { record } from './audit.js';
 
-// Notes for one owner, newest first.
-export function listNotes(ownerId) {
+const withArchived = (note) => (note ? { ...note, archived: note.archived === true } : null);
+
+// Notes for one owner, newest first. Only active notes unless { archived: true }.
+export function listNotes(ownerId, { archived = false } = {}) {
   return all('notes')
-    .filter((n) => n.ownerId === ownerId)
+    .filter((n) => n.ownerId === ownerId && (n.archived === true) === archived)
+    .map(withArchived)
     .sort((a, b) => b.createdAt - a.createdAt);
 }
 
 export function getNote(ownerId, id) {
   const note = get('notes', id);
-  return note && note.ownerId === ownerId ? note : null;
+  return note && note.ownerId === ownerId ? withArchived(note) : null;
+}
+
+export function setArchived(ownerId, id, archived) {
+  if (!getNote(ownerId, id)) return null;
+  invalidate(`notes:${ownerId}`);
+  record(ownerId, archived ? 'note.archive' : 'note.unarchive', id);
+  return withArchived(update('notes', id, { archived }));
 }
 
 export function createNote(ownerId, input) {
@@ -24,6 +34,7 @@ export function createNote(ownerId, input) {
     body: requireString(input, 'body', { max: 10000 }),
     tags: optionalTags(input),
     createdAt: Date.now(),
+    archived: false,
   };
   insert('notes', note);
   invalidate(`notes:${ownerId}`);
@@ -39,7 +50,7 @@ export function updateNote(ownerId, id, input) {
   if (input.tags !== undefined) patch.tags = optionalTags(input);
   invalidate(`notes:${ownerId}`);
   record(ownerId, 'note.update', id);
-  return update('notes', id, patch);
+  return withArchived(update('notes', id, patch));
 }
 
 export function deleteNote(ownerId, id) {
diff --git a/src/services/tags.js b/src/services/tags.js
index a5a9ea2..cb61d31 100644
--- a/src/services/tags.js
+++ b/src/services/tags.js
@@ -6,7 +6,7 @@ export function tagCounts(ownerId) {
   return cached(`notes:${ownerId}:tags`, () => {
     const counts = {};
     for (const note of all('notes')) {
-      if (note.ownerId !== ownerId) continue;
+      if (note.ownerId !== ownerId || note.archived === true) continue;
       for (const tag of note.tags) counts[tag] = (counts[tag] ?? 0) + 1;
     }
     return counts;
diff --git a/src/utils/format.js b/src/utils/format.js
index 24a3a09..6917f3c 100644
--- a/src/utils/format.js
+++ b/src/utils/format.js
@@ -20,6 +20,7 @@ export function noteSummary(note) {
     preview: truncate(note.body, 40),
     created: formatDate(note.createdAt),
     tags: [...note.tags].sort(),
+    archived: note.archived === true,
   };
 }
 
diff --git a/tests/api.test.js b/tests/api.test.js
index 32d499e..160a323 100644
--- a/tests/api.test.js
+++ b/tests/api.test.js
@@ -37,3 +37,50 @@ test('search ranks title matches first', () => {
   const res = as('u1', { method: 'GET', path: '/search', query: { q: 'list' } });
   assert.deepEqual(res.body.map((n) => n.title), ['Book list']);
 });
+
+const archive = (u, id, verb = 'archive') => as(u, { method: 'POST', path: `/notes/${id}/${verb}` });
+
+test('archive returns the updated note and hides it from lists, search and tag counts', () => {
+  assert.equal(as('u1', { method: 'GET', path: '/tags/counts' }).body.work, 4); // warm cache
+  const res = archive('u1', 'n2');
+  assert.equal(res.status, 200);
+  assert.equal(res.body.archived, true);
+  const list = as('u1', { method: 'GET', path: '/notes' }).body;
+  assert.equal(list.length, 7);
+  assert.ok(list.every((n) => n.archived === false && n.id !== 'n2'));
+  assert.deepEqual(as('u1', { method: 'GET', path: '/search', query: { q: 'book' } }).body, []);
+  assert.equal(as('u1', { method: 'GET', path: '/tags/counts' }).body.work, 3);
+});
+
+test('archived=true lists only archived notes; GET by id still works', () => {
+  archive('u1', 'n2');
+  const res = as('u1', { method: 'GET', path: '/notes', query: { archived: 'true' } });
+  assert.deepEqual(res.body.map((n) => [n.id, n.archived]), [['n2', true]]);
+  const one = as('u1', { method: 'GET', path: '/notes/n2' });
+  assert.equal(one.status, 200);
+  assert.equal(one.body.archived, true);
+  assert.equal(as('u1', { method: 'GET', path: '/notes/n3' }).body.archived, false);
+});
+
+test('unarchive restores the note', () => {
+  archive('u1', 'n2');
+  const res = archive('u1', 'n2', 'unarchive');
+  assert.equal(res.status, 200);
+  assert.equal(res.body.archived, false);
+  assert.equal(as('u1', { method: 'GET', path: '/notes' }).body.length, 8);
+  assert.equal(as('u1', { method: 'GET', path: '/notes', query: { archived: 'true' } }).body.length, 0);
+});
+
+test("archiving someone else's or a missing note is 404", () => {
+  assert.equal(archive('u1', 'n1').status, 404); // owned by u2
+  assert.equal(archive('u1', 'n1', 'unarchive').status, 404);
+  assert.equal(archive('u1', 'nope').status, 404);
+  assert.equal(as('u2', { method: 'GET', path: '/notes/n1' }).body.archived, false);
+});
+
+test('created and patched notes include archived', () => {
+  const created = as('u1', { method: 'POST', path: '/notes', body: { title: 'New', body: 'Text' } });
+  assert.equal(created.body.archived, false);
+  const patched = as('u1', { method: 'PATCH', path: `/notes/${created.body.id}`, body: { title: 'X' } });
+  assert.equal(patched.body.archived, false);
+});