diff --git a/README.md b/README.md
index 881cfac..4ecc287 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,15 @@ npm run build      # сборка в dist/ — можно положить на
 npm run typecheck
 ```
 
+Для автоматических проверок сетевого клиента нужен Node.js 22+: `npm test`.
+Тесты проверяют таймауты, переключение серверов и отмену без обращения к сети.
+
+Данные сначала запрашиваются у `maps.mail.ru`, затем у `overpass-api.de` и
+`overpass.private.coffee`. На каждый запрос отводится 45 секунд, включая загрузку
+ответа; после ошибки или таймаута используется следующий сервер. Лимит обработки
+запроса на стороне Overpass — 30 секунд. Кнопка «Отмена» прерывает запрос и ожидание
+перед повтором.
+
 Без интернета можно проверить на образце: «Другие способы» → «Сгенерировать из выгрузки
 Overpass» → `samples/balzers-2013.json` (Бальцерс, Лихтенштейн, данные OSM 2013 года).
 
diff --git a/package.json b/package.json
index 3825089..164a3a7 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "description": "Генератор подробной карты города по данным OpenStreetMap: планировки, этажи и мебель простыми фигурами, вид сверху.",
   "type": "module",
   "scripts": {
+    "test": "tsx --test scripts/*.test.ts",
     "dev": "node build.mjs --serve",
     "build": "node build.mjs",
     "typecheck": "tsc -p .",
diff --git a/scripts/overpass.test.ts b/scripts/overpass.test.ts
new file mode 100644
index 0000000..a7bbedb
--- /dev/null
+++ b/scripts/overpass.test.ts
@@ -0,0 +1,86 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { fetchOverpass, OVERPASS_ENDPOINTS, type BBox } from '../src/osm/overpass';
+
+const bbox: BBox = [35.3, -112.9, 35.31, -112.89];
+const elements = [{ type: 'node', id: 1 }];
+const ok = () => Response.json({ elements });
+const pending = (signal: AbortSignal) => new Promise<Response>((_, reject) => {
+  signal.addEventListener('abort', () => reject(new DOMException('Aborted', 'AbortError')), { once: true });
+});
+
+test('starts with Mail.ru and falls back after an HTTP error', async (t) => {
+  const urls: string[] = [];
+  t.mock.method(globalThis, 'fetch', async (url: string) => {
+    urls.push(url);
+    return urls.length === 1 ? new Response('', { status: 406 }) : ok();
+  });
+  assert.deepEqual(await fetchOverpass(bbox), elements);
+  assert.match(urls[0], /maps\.mail\.ru/);
+  assert.deepEqual(urls, OVERPASS_ENDPOINTS.slice(0, 2));
+});
+
+test('times out a hanging request and tries the next server', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  let calls = 0;
+  t.mock.method(globalThis, 'fetch', (_url: string, init: RequestInit) => {
+    return ++calls === 1 ? pending(init.signal!) : Promise.resolve(ok());
+  });
+  const result = fetchOverpass(bbox);
+  t.mock.timers.tick(45_000);
+  assert.deepEqual(await result, elements);
+  assert.equal(calls, 2);
+});
+
+test('timeout also covers downloading the response body', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  let calls = 0;
+  t.mock.method(globalThis, 'fetch', async (_url: string, init: RequestInit) => {
+    if (++calls > 1) return ok();
+    return { ok: true, status: 200, json: () => pending(init.signal!) };
+  });
+  const result = fetchOverpass(bbox);
+  await Promise.resolve();
+  t.mock.timers.tick(45_000);
+  assert.deepEqual(await result, elements);
+  assert.equal(calls, 2);
+});
+
+test('user cancellation stops the active request without fallback', async (t) => {
+  const controller = new AbortController();
+  const fetch = t.mock.method(globalThis, 'fetch', (_url: string, init: RequestInit) => pending(init.signal!));
+  const result = fetchOverpass(bbox, undefined, controller.signal);
+  controller.abort();
+  await assert.rejects(result, { name: 'AbortError' });
+  assert.equal(fetch.mock.callCount(), 1);
+});
+
+test('user cancellation interrupts the retry delay', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  const controller = new AbortController();
+  const fetch = t.mock.method(globalThis, 'fetch', async () => new Response('', { status: 429 }));
+  const result = fetchOverpass(bbox, undefined, controller.signal);
+  await Promise.resolve();
+  controller.abort();
+  await assert.rejects(result, { name: 'AbortError' });
+  assert.equal(fetch.mock.callCount(), 1);
+});
+
+test('an already cancelled operation makes no requests', async (t) => {
+  const fetch = t.mock.method(globalThis, 'fetch', async () => ok());
+  await assert.rejects(fetchOverpass(bbox, undefined, AbortSignal.abort()), { name: 'AbortError' });
+  assert.equal(fetch.mock.callCount(), 0);
+});
+
+test('reports failure when every server times out', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  const fetch = t.mock.method(globalThis, 'fetch', (_url: string, init: RequestInit) => pending(init.signal!));
+  const result = fetchOverpass(bbox);
+  const check = assert.rejects(result, /Таймаут.*45 секунд/);
+  for (let i = 0; i < OVERPASS_ENDPOINTS.length; i++) {
+    t.mock.timers.tick(45_000);
+    await Promise.resolve();
+  }
+  await check;
+  assert.equal(fetch.mock.callCount(), OVERPASS_ENDPOINTS.length);
+});
diff --git a/src/osm/overpass.ts b/src/osm/overpass.ts
index dcebb86..2ba5f7e 100644
--- a/src/osm/overpass.ts
+++ b/src/osm/overpass.ts
@@ -15,14 +15,32 @@ export interface OsmElement {
 }
 
 export const OVERPASS_ENDPOINTS = [
+  'https://maps.mail.ru/osm/tools/overpass/api/interpreter',
   'https://overpass-api.de/api/interpreter',
   'https://overpass.private.coffee/api/interpreter',
-  'https://maps.mail.ru/osm/tools/overpass/api/interpreter',
 ];
 
+const REQUEST_TIMEOUT_MS = 45_000;
+
+function waitForRetry(ms: number, signal?: AbortSignal): Promise<void> {
+  return new Promise((resolve, reject) => {
+    const cancel = () => {
+      clearTimeout(timer);
+      signal?.removeEventListener('abort', cancel);
+      reject(new DOMException('Отменено', 'AbortError'));
+    };
+    const timer = setTimeout(() => {
+      signal?.removeEventListener('abort', cancel);
+      resolve();
+    }, ms);
+    signal?.addEventListener('abort', cancel, { once: true });
+    if (signal?.aborted) cancel();
+  });
+}
+
 export function buildQuery(b: BBox): string {
   const bb = `(${b[0]},${b[1]},${b[2]},${b[3]})`;
-  return `[out:json][timeout:120];
+  return `[out:json][timeout:30];
 (
   way["building"]${bb};
   relation["building"]["type"="multipolygon"]${bb};
@@ -56,27 +74,42 @@ export async function fetchOverpass(b: BBox, onStatus?: (s: string) => void, sig
   let lastErr: unknown = null;
   for (const url of OVERPASS_ENDPOINTS) {
     for (let attempt = 0; attempt < 2; attempt++) {
+      if (signal?.aborted) throw new DOMException('Отменено', 'AbortError');
+      const controller = new AbortController();
+      const cancel = () => controller.abort();
+      signal?.addEventListener('abort', cancel, { once: true });
+      let timedOut = false;
+      const timer = setTimeout(() => {
+        timedOut = true;
+        controller.abort();
+      }, REQUEST_TIMEOUT_MS);
       try {
-        onStatus?.(`Запрос к ${new URL(url).host}${attempt ? ' (повтор)' : ''}…`);
+        onStatus?.(`Запрос к ${new URL(url).host}${attempt ? ' (повтор)' : ''} — до 45 секунд…`);
         const res = await fetch(url, {
           method: 'POST',
           body: 'data=' + encodeURIComponent(query),
           headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
-          signal,
+          signal: controller.signal,
         });
         if (res.status === 429 || res.status === 504) {
           lastErr = new Error(`Сервер перегружен (${res.status})`);
-          await new Promise((r) => setTimeout(r, 3000 * (attempt + 1)));
+          clearTimeout(timer);
+          if (attempt === 0) await waitForRetry(3000, signal);
           continue;
         }
         if (!res.ok) throw new Error(`HTTP ${res.status}`);
         const json = await res.json();
+        if (signal?.aborted) throw new DOMException('Отменено', 'AbortError');
         if (json.remark && /error|timed out|runtime/i.test(json.remark)) throw new Error(json.remark);
+        if (!Array.isArray(json.elements)) throw new Error('Сервер вернул ответ без списка elements');
         return json.elements as OsmElement[];
       } catch (e) {
-        if (signal?.aborted) throw e;
-        lastErr = e;
+        if (signal?.aborted) throw new DOMException('Отменено', 'AbortError');
+        lastErr = timedOut ? new Error(`Таймаут ${new URL(url).host}: 45 секунд`) : e;
         break;
+      } finally {
+        clearTimeout(timer);
+        signal?.removeEventListener('abort', cancel);
       }
     }
   }