diff --git a/docs/08-match-flow-next-steps.md b/docs/08-match-flow-next-steps.md
index b9962f1..82094f0 100644
--- a/docs/08-match-flow-next-steps.md
+++ b/docs/08-match-flow-next-steps.md
@@ -47,14 +47,15 @@ match server e2e, svelte-check (no new errors), production build, lobby SSR.
 
 ## Known gaps / follow-ups
 
-- **Reconnect**: after a reload the game isn't rejoined automatically
-  (`GET /api/games/[id]` exists; needs a "current game" lookup + auto-enter).
-- **Escape** leaves the board view but the match stays active (no
-  resign/abandon lifecycle yet).
+- ✅ **Reconnect** (done, PR #10): `GET /api/games/current` + auto-enter after
+  the lobby socket connects.
+- ✅ **Resign** (done, PR #12): Escape in an active match confirms → resigns
+  (`POST /api/games/[id]/resign` → `game_over` delta → opponent wins).
 - Local sandbox `movePiece` still swaps pieces (no capture) — match mode is
   unaffected (server board is authoritative).
 - No optimistic move application (small perceived latency: move renders when
   the delta returns).
+- No draw offer / threefold / clocks (Tier 5 game features).
 
 ---
 
diff --git a/e2e/match.e2e.mjs b/e2e/match.e2e.mjs
index 8048313..6a664e9 100644
--- a/e2e/match.e2e.mjs
+++ b/e2e/match.e2e.mjs
@@ -11,9 +11,16 @@ for (const r of (await (await p1('/api/rooms')).json()).rooms.filter((r) => r.ow
 	await p1(`/api/rooms/${r.id}`, { method: 'DELETE' });
 }
 
-// NOTE: earlier runs may leave active games (no resign/abandon endpoint yet);
-// /api/games/current returns the NEWEST active game, so the assertions below
-// stay valid on repeat runs.
+// clean slate: resign any active games left over from earlier runs
+for (const p of [p1, p2]) {
+	for (let i = 0; i < 10; i++) {
+		const { game } = await (await p('/api/games/current')).json();
+		if (!game) break;
+		await p(`/api/games/${game.id}/resign`, { method: 'POST' });
+	}
+}
+const pre = await (await p1('/api/games/current')).json();
+assert(pre.game === null, 'no active game before the match (leftovers resigned)');
 
 // create + join
 const createRes = await p1('/api/rooms', {
@@ -97,6 +104,31 @@ assert(stateRes.status === 200, 'participant can GET game state');
 const unauth = await fetch(`${BASE}/api/games/${game.id}`);
 assert(unauth.status === 401, 'unauthenticated GET rejected');
 
+// resign: black (p2) resigns -> white (p1) wins, both get game_over
+const resignRes = await p2(`/api/games/${game.id}/resign`, { method: 'POST' });
+assert(resignRes.status === 200, `resign accepted (200, got ${resignRes.status})`);
+const resigned = (await resignRes.json()).game;
+assert(resigned.status === 'finished' && resigned.winnerId === game.whitePlayerId, 'resigning as black makes white the winner');
+
+await wait(200);
+const over1 = c1.msgs.find((m) => m.kind === 'game_over');
+assert(over1 && over1.winnerId === game.whitePlayerId && over1.reason === 'resign', 'p1 received game_over(resign) with the right winner');
+assert(c2.msgs.some((m) => m.kind === 'game_over'), 'p2 received game_over too');
+
+// game is over: further moves and repeat resigns are rejected
+const postMove = await p2(`/api/games/${game.id}/move`, {
+	method: 'POST', headers: { 'content-type': 'application/json' },
+	body: JSON.stringify({ from: [2, 5, 2], to: [2, 4, 2] })
+});
+assert(postMove.status === 409, `move after game over rejected (409, got ${postMove.status})`);
+const resignAgain = await p2(`/api/games/${game.id}/resign`, { method: 'POST' });
+assert(resignAgain.status === 409, `second resign rejected (409, got ${resignAgain.status})`);
+
+// no active game remains for either player (reconnect returns null)
+const post1 = await (await p1('/api/games/current')).json();
+const post2 = await (await p2('/api/games/current')).json();
+assert(post1.game === null && post2.game === null, 'no active game after resign (e2e leaves no leftovers)');
+
 c1.ws.close();
 c2.ws.close();
 finish('MATCH E2E');
diff --git a/package.json b/package.json
index 1e71960..ec997c9 100644
--- a/package.json
+++ b/package.json
@@ -12,8 +12,8 @@
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
 		"lint": "prettier --plugin-search-dir . --check . && eslint .",
 		"format": "prettier --plugin-search-dir . --write .",
-		"test": "vitest run",
-		"test:watch": "vitest",
+		"test": "svelte-kit sync && vitest run",
+		"test:watch": "svelte-kit sync && vitest",
 		"e2e": "node e2e/seed.mjs && node e2e/auth.e2e.mjs && node e2e/rooms.e2e.mjs && node e2e/match.e2e.mjs",
 		"model-pipeline:run": "node scripts/model-pipeline.js"
 	},
diff --git a/src/lib/async/websockets/match/handler.ts b/src/lib/async/websockets/match/handler.ts
index 1335108..c61ba04 100644
--- a/src/lib/async/websockets/match/handler.ts
+++ b/src/lib/async/websockets/match/handler.ts
@@ -49,11 +49,21 @@ export async function enterMatchById(gameId: string): Promise<void> {
 	await enterMatch(game);
 }
 
-/** Apply a server-confirmed move: the delta's board is authoritative. */
+/** Apply a server-confirmed delta: the server state is authoritative. */
 export function matchDeltaHandler(delta: MatchDelta): void {
 	const current = get(gameStore);
 	if (!current) return;
 
+	if (delta.kind === 'game_over') {
+		gameStore.set({ ...current, status: 'finished', winnerId: delta.winnerId });
+		const won = delta.winnerId === get(userStore).id;
+		pushNotification({
+			message: won ? 'You won — your opponent resigned.' : 'You resigned.',
+			type: won ? 'success' : 'error'
+		});
+		return;
+	}
+
 	hydrateBoard(delta.board);
 	gameStore.set({
 		...current,
@@ -72,6 +82,19 @@ export function matchDeltaHandler(delta: MatchDelta): void {
 	}
 }
 
+/** Resign the active game; the game_over delta finishes the UI transition. */
+export async function resignGame(): Promise<boolean> {
+	const game = get(gameStore);
+	if (!game || game.status !== 'active') return true; // nothing to resign
+
+	const res = await fetch(`/api/games/${game.id}/resign`, { method: 'POST' });
+	if (!res.ok && res.status !== 409) {
+		pushNotification({ message: 'Could not resign', type: 'error' });
+		return false;
+	}
+	return true;
+}
+
 /** POST a move; the resulting board arrives via the MATCH delta. */
 export async function sendMove(from: number[], to: number[]): Promise<void> {
 	const game = get(gameStore);
diff --git a/src/lib/async/websockets/rooms/handler.ts b/src/lib/async/websockets/rooms/handler.ts
index d81e24e..f5dfd3c 100644
--- a/src/lib/async/websockets/rooms/handler.ts
+++ b/src/lib/async/websockets/rooms/handler.ts
@@ -44,6 +44,7 @@ export const roomsEventHandler = (event: MessageEvent) => {
 			break;
 		}
 		case 'move_applied':
+		case 'game_over':
 			matchDeltaHandler(delta);
 			break;
 	}
diff --git a/src/lib/async/websockets/types.ts b/src/lib/async/websockets/types.ts
index 6c97c8a..5b05f37 100644
--- a/src/lib/async/websockets/types.ts
+++ b/src/lib/async/websockets/types.ts
@@ -19,13 +19,20 @@ export type RoomDelta =
 	| { kind: 'game_started'; game: GameSummary };
 
 // Deltas broadcast on the per-game MATCH:<gameId> topic.
-export type MatchDelta = {
-	kind: 'move_applied';
-	from: Coord;
-	to: Coord;
-	turn: Side;
-	board: Record<string, PieceState>;
-	status: 'active' | 'finished';
-	winnerId: string | null;
-	captured: PieceState | null;
-};
+export type MatchDelta =
+	| {
+			kind: 'move_applied';
+			from: Coord;
+			to: Coord;
+			turn: Side;
+			board: Record<string, PieceState>;
+			status: 'active' | 'finished';
+			winnerId: string | null;
+			captured: PieceState | null;
+	  }
+	| {
+			kind: 'game_over';
+			status: 'finished';
+			winnerId: string | null;
+			reason: 'resign';
+	  };
diff --git a/src/lib/components/App.svelte b/src/lib/components/App.svelte
index 91ac591..022f446 100644
--- a/src/lib/components/App.svelte
+++ b/src/lib/components/App.svelte
@@ -1,22 +1,53 @@
 <script lang="ts">
+	import { get } from 'svelte/store';
+	import { getModalStore, type ModalSettings } from '@skeletonlabs/skeleton';
 	import { decreaseOffsetY, increaseOffsetY } from '$lib/store/camera';
 	import userStore from '$lib/store/user';
+	import { gameStore, clearGame } from '$lib/store/game';
+	import { resignGame } from '$lib/async/websockets/match/handler';
 	import Table from './Table/Table.svelte';
 	import BorderWrapper from './borderWrapper/BorderWrapper.svelte';
 	import CreateRoom from './createRoom/CreateRoom.svelte';
 	import MyRooms from './myRooms/MyRooms.svelte';
 
+	const modalStore = getModalStore();
+
+	const leaveBoard = () => {
+		clearGame();
+		userStore.update((user) => ({ ...user, playing: false }));
+	};
+
+	const onEscape = () => {
+		const game = get(gameStore);
+
+		// no match, or the match is over: just leave the board view
+		if (!game || game.status !== 'active') {
+			leaveBoard();
+			return;
+		}
+
+		const modal: ModalSettings = {
+			type: 'confirm',
+			title: 'Resign?',
+			backdropClasses: 'glass black-glass',
+			modalClasses: 'bg-white',
+			body: 'Leaving the board resigns the match. Resign and return to the lobby?',
+			response: (confirmed: boolean) => {
+				if (!confirmed) return;
+				void resignGame().then((ok) => {
+					if (ok) leaveBoard();
+				});
+			}
+		};
+		modalStore.trigger(modal);
+	};
+
 	/** @param {KeyboardEvent} event */
 	function handleKeydown(event: KeyboardEvent) {
 		if (playing) {
 			switch (event.key) {
 				case 'Escape':
-					userStore.update((user) => {
-						return {
-							...user,
-							playing: false
-						};
-					});
+					onEscape();
 					break;
 
 				case 'w':
diff --git a/src/lib/server/game/service.ts b/src/lib/server/game/service.ts
index c36ff18..c4cbfea 100644
--- a/src/lib/server/game/service.ts
+++ b/src/lib/server/game/service.ts
@@ -93,6 +93,28 @@ export async function getGame(gameId: string): Promise<GameState | null> {
 	return game ? toState(game) : null;
 }
 
+/** Resign: the opponent wins immediately; both players get a game_over delta. */
+export async function resignGame(gameId: string, userId: string): Promise<GameState> {
+	const game = await prisma.game.findUnique({ where: { id: gameId } });
+	if (!game) throw new Error('GAME_NOT_FOUND');
+	if (game.status !== 'active') throw new Error('GAME_OVER');
+
+	const isWhite = userId === game.whitePlayerId;
+	const isBlack = userId === game.blackPlayerId;
+	if (!isWhite && !isBlack) throw new Error('NOT_A_PARTICIPANT');
+
+	const winnerId = isWhite ? game.blackPlayerId : game.whitePlayerId;
+	const updated = await prisma.game.update({
+		where: { id: gameId },
+		data: { status: 'finished', winnerId }
+	});
+
+	const delta: MatchDelta = { kind: 'game_over', status: 'finished', winnerId, reason: 'resign' };
+	publish(matchTopic(gameId), JSON.stringify(delta));
+
+	return toState(updated);
+}
+
 /** The player's active game, if any — used to reconnect after a reload. */
 export async function getCurrentGameFor(userId: string): Promise<GameState | null> {
 	const game = await prisma.game.findFirst({
diff --git a/src/routes/api/games/[id]/resign/+server.ts b/src/routes/api/games/[id]/resign/+server.ts
new file mode 100644
index 0000000..5acf571
--- /dev/null
+++ b/src/routes/api/games/[id]/resign/+server.ts
@@ -0,0 +1,17 @@
+import { json, error } from '@sveltejs/kit';
+import { resignGame } from '$lib/server/game/service';
+
+export const POST = async ({ params, locals }) => {
+	if (!locals.user) throw error(401, 'Not authenticated');
+
+	try {
+		const game = await resignGame(params.id, locals.user.id);
+		return json({ game });
+	} catch (e) {
+		const msg = e instanceof Error ? e.message : 'UNKNOWN';
+		if (msg === 'GAME_NOT_FOUND') throw error(404, msg);
+		if (msg === 'NOT_A_PARTICIPANT') throw error(403, msg);
+		if (msg === 'GAME_OVER') throw error(409, msg);
+		throw error(500, msg);
+	}
+};