Polly.js Alternatives: Recording and Replaying HTTP in JavaScript

Tested with @pollyjs/core 6.0.6 (+ adapter-fetch 6.0.7), nock 15.0.6, msw 3.0.5, @playwright/test 1.65.0 (Chromium), talkback 4.2.0, proxay 1.9.0, @sgedda/mockifyer-core 1.10.181 / -fetch 1.8.100 / -axios 1.10.32, axios 1.20.0 on Node 22.23.3; 2026-10-15. On 2026-11-10, record and replay with MOCKIFYER_RECORD_RESPONSES=true stored and replayed response bodies on core 1.10.190 / fetch 1.8.106 and on core 1.10.187 / fetch 1.8.104. On 2026-11-11, nock 15.0.6, msw 3.0.5 and @playwright/test 1.65.0 re-ran the original record/replay tests and passed (Node 24.22.1 for the upstream API, Playwright via Node 22.23.4).

Looking for Polly.js alternatives? Polly.JS still gets about 200,000 npm installs a week, but @pollyjs/core hasn’t had a release since July 20, 2023. The only release since then is @pollyjs/adapter-fetch 6.0.7, from May 31, 2025. The repo isn’t archived or deprecated, and it still works. But for new suites, you’ll want a maintained recorder.

Disclosure. Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev. It’s one of the tools on this page, and it gets the same template, tests and limits list as every other tool, and it isn’t ranked as “best”. We have no affiliate links and no commercial ties to any other project here.

Tested with @pollyjs/core 6.0.6, nock 15.0.6, msw 3.0.5, @playwright/test 1.65.0, talkback 4.2.0, proxay 1.9.0 and Mockifyer (core 1.10.181, fetch 1.8.100, axios 1.10.32) on Node 22.23.3, 2026-10-15. For each one, we recorded a local API, changed its responses, and confirmed that the replay returned the recorded data. WireMock, Mockoon and test-proxy-recorder weren’t run; those sections cite their docs. On 2026-11-10, record and replay with MOCKIFYER_RECORD_RESPONSES=true stored and replayed response bodies on core 1.10.190 / fetch 1.8.106 and on core 1.10.187 / fetch 1.8.104; the original record/replay tests remain those of 2026-10-15 on 1.10.181. On 2026-11-11 we re-ran those record/replay tests on nock 15.0.6 (released 2026-11-06, Europe/Stockholm), msw 3.0.5 (released 2026-11-11) and Playwright 1.65.0 (released 2026-11-05), and they passed.

TL;DR

Polly.js still installs about 200K times a week, but its core hasn’t had a release since July 2023, so new projects should pick a maintained recorder: nock’s nock.back for Node-only tests, Playwright’s routeFromHAR for browser E2E, or a proxy like Talkback for any language. If you need record/replay for fetch and axios in React Native/Expo, with editable per-request JSON mocks and scenarios, Mockifyer covers that case (disclosure: mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.)

Is Polly.js still maintained?

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The repo has 10,249 stars and 61 open issues, and it’s not archived (2026-10-15). @pollyjs/core had 200,347 downloads in the week of October 6–12, 2026.

What still works. On Node 22, Polly 6.0.6 recorded and replayed axios (via adapter-node-http) and native fetch (via adapter-fetch with context: globalThis). In record mode it logged a harmless “browser is offline” warning.

The risks. adapter-node-http depends on nock ^13, two majors behind, and on its own it didn’t see native fetch: our replay reached the live server. Future Node changes would need a release that may never come.

Staying on Polly short-term is a valid choice if your recordings replay and Node isn’t changing. Pin versions, replay only in CI, and plan the move.

What record/replay gives you

Hand-written mocks (MSW handlers, Nock interceptors, Mirage JS models) describe what you think the API returns. Recorders capture what it did return:

• Fixtures from real traffic, including fields you’d never type by hand.
• Deterministic CI: replay only, with no network.
• Drift checks: re-record, and git diff shows what changed.

The cost: recordings can capture tokens, and they go stale.

How we compared

We compared interception, runtimes, clients, record modes, replay-only CI behaviour, storage, matching, scrubbing and maintenance. Downloads are npm’s figures for October 6–12, 2026.

Polly.js alternatives at a glance

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*Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

The alternatives

nock + nock.back

The most-used maintained Node option: record into a JSON fixture once, then replay.

import nock from 'nock';

nock.back.fixtures = new URL('./__nock-fixtures__', import.meta.url).pathname;
nock.back.setMode(process.env.NOCK_BACK_MODE ?? 'dryrun'); // 'record' locally, 'lockdown' in CI

const { nockDone } = await nock.back('users.json', {
  // drop cookies before the fixture is written
  afterRecord: (defs) => defs.map(({ rawHeaders, ...def }) => {
    const { 'set-cookie': _drop, ...headers } = rawHeaders ?? {};
    return { ...def, rawHeaders: headers };
  }),
});
const user = await (await fetch('http://localhost:4599/users/1')).json();
nockDone();

• How it records: in-process; afterRecord lets you scrub what’s recorded.
• Where it runs: Node only (Nock 15: Node ≥20.12.1, ESM-only).
• Storage format: a JSON array of Nock definitions per fixture.
• Matching: host, method, path and body. Request headers aren’t recorded by default.
• Re-record workflow: update re-records, record adds what’s missing, lockdown replays and blocks the rest (all tested with fetch and axios). Unmatched requests to a recorded host got a 501.
• Maintenance: 15.0.6, 2026-11-06; ~6.3M weekly downloads.
• Best for: Node services and libraries.
• Limits: no browser or React Native; modes are managed via env var; no HAR import.

See Nock and MSW vs Nock.

MSW + recorded fixtures/HAR

MSW has no built-in recorder (none in msw 3.0.5’s exports or docs), but it can replay captured traffic. This loader replayed a Polly HAR in our MSW 3 test:

import fs from 'node:fs';
import { http, HttpResponse } from 'msw';
import { setupServer } from 'msw/node';

function handlersFromHar(file) {
  const { log } = JSON.parse(fs.readFileSync(file, 'utf8'));
  return log.entries.map(({ request, response }) =>
    http[request.method.toLowerCase()](request.url, () =>
      new HttpResponse(response.content.text, {
        status: response.status,
        headers: { 'content-type': response.content.mimeType },
      })));
}
const server = setupServer(...handlersFromHar('./recordings/users.har'));
server.listen({ onUnhandledFrame: 'error' });

The official @mswjs/source 0.5.0 has fromTraffic(har) and declares msw ^2.10.0. It worked with msw 2.15.0, but failed to import with 3.0.3 (no export named 'cleanUrl').

• How it records: it doesn’t. Capture with another tool (Playwright, DevTools, Polly).
• Where it runs: Node, browser, Storybook; MSW 3 needs Node ≥22.12.
• Storage format: your choice.
• Matching: your handlers. This is the most flexible option.
• Re-record workflow: re-capture with your other tool.
• Maintenance: 3.0.5, 2026-11-11; ~23M weekly downloads.
• Best for: teams already on MSW.
• Limits: no recorder; @mswjs/source isn’t MSW 3-ready; @msw/react-native is a 404 on npm (2026-10-15).

See MSW.

Playwright routeFromHAR

Record/replay for browser E2E is built into Playwright:

await page.routeFromHAR('./hars/users.har', {
  url: '**/users/**',
  update: !!process.env.UPDATE_HAR, // record when set, replay otherwise
  notFound: 'abort',                // fail requests missing from the HAR
});

• How it records: update: true writes live traffic into the HAR (recordHar also works).
• Where it runs: browser pages in Playwright tests, not SSR or Node test runners.
• Storage format: HAR; in our run, the bodies went into sidecar files (updateContent).
• Matching: URL and method strictly, plus the POST payload; ties go to the most matching headers.
• Re-record workflow: re-run with UPDATE_HAR=1. Our replay returned the recorded body after the API changed.
• Maintenance: 1.65.0, 2026-11-05.
• Best for: E2E suites.
• Limits: requests handled by a Service Worker aren’t served from the HAR (use serviceWorkers: 'block'); browser traffic only.

See Playwright.

Talkback

An HTTP proxy that records “tapes”; point any app at it.

import talkback from 'talkback';
const { RecordMode, FallbackMode } = talkback.Options;

const server = talkback({
  host: 'https://api.example.com',
  port: 5544,
  path: './tapes',
  record: process.env.CI ? RecordMode.DISABLED : RecordMode.NEW,
  fallbackMode: FallbackMode.NOT_FOUND,
  ignoreHeaders: ['content-length', 'host', 'authorization'],
});
await server.start();

• How it records: NEW records misses, OVERWRITE always re-records, DISABLED only replays.
• Where it runs: a Node process; the client can be anything.
• Storage format: one JSON5 tape per request, with readable bodies.
• Matching: method, URL, headers (minus ignoreHeaders) and body, with custom matcher hooks.
• Re-record workflow: OVERWRITE, or delete tapes. DISABLED replayed, with a 404 for unknown paths; ignored headers weren’t saved.
• Maintenance: 4.2.0, 2024-07-10; last push 2024-08-31.
• Best for: polyglot stacks.
• Limits: no release in two years; needs a base-URL switch and an extra process.

Proxay

A record/replay proxy from Airtasker, with YAML tapes.

npx proxay --mode record --host https://api.example.com --tapes-dir ./tapes --redact-headers authorization
npx proxay --mode replay --tapes-dir ./tapes

• How it records: as a proxy: record, replay, passthrough.
• Where it runs: a Node CLI; any client.
• Storage format: YAML tapes; --redact-headers stored XXXX.
• Matching: best-effort, or --exact-request-matching.
• Re-record workflow: record a fresh tape. Unknown paths returned a 500 in replay.
• Maintenance: commits through 2026-10-15 and a GitHub v2.0.0 release (2026-01-29), but npm’s latest is 1.9.0 (2024-05-15).
• Best for: proxy recording with redaction.
• Limits: v2 isn’t on npm; 87 stars.

test-proxy-recorder

A new Playwright recorder: proxy for SSR, HAR for the browser. Not run by us.

• How it records: record, replay and transparent modes, set per test (one mode at a time).
• Where it runs: Playwright, with Next.js and TanStack Start SSR (per its docs).
• Storage format: .mock.json plus HAR.
• Matching: method, path and a query-string hash; repeats replay in recorded order.
• Re-record workflow: re-run in record mode.
• Maintenance: 1.4.1, 2026-10-13; one maintainer; created November 2025.
• Best for: SSR E2E suites where routeFromHAR misses the server calls.
• Limits: ~263 weekly downloads; its comparison table is a vendor claim.

WireMock and Mockoon (record modes)

Out-of-process mock servers that can learn from real traffic. Not run by us.

• How they record: WireMock proxies and records (or snapshots) stub mappings. Mockoon’s desktop app records one route per method and path, with proxy mode.
• Where they run: WireMock is Java (JAR, Docker, npm wrapper); Mockoon is a desktop app or CLI. Both serve any language.
• Storage format: WireMock JSON mappings; a Mockoon environment file.
• Matching: WireMock matchers (JSON bodies use equalToJson); Mockoon route rules.
• Re-record workflow: WireMock: record again; Mockoon: delete the route first.
• Maintenance: WireMock 3.13.2 (2025-11-14), with 4.0 betas through 2026-10-21; Mockoon 9.10.0 (2026-10-29).
• Best for: shared mock servers: a GUI (Mockoon), or stateful scenarios (WireMock).
• Limits: heavier than in-process libraries; Mockoon doesn’t update recorded routes.

See WireMock and Mockoon.

Mockifyer

Disclosure: Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

Record/replay for fetch and axios, with editable JSON, scenarios and date control. In a fresh project, this recorded and replayed only with the env var shown:

// run with MOCKIFYER_RECORD_DEFAULT_ALWAYS_USE_REAL_API=false and MOCKIFYER_RECORD_RESPONSES=true; set MOCKIFYER_SCENARIO or recordings land in the 24h `_scratch` bucket
import { setupMockifyer } from '@sgedda/mockifyer-fetch';

const record = process.env.MOCKIFYER_RECORD === 'true';
setupMockifyer({
  mockDataPath: './mock-data',
  useGlobalFetch: true,               // patch global fetch in Node
  recordMode: record,
  failOnMissingMock: !record,         // CI: throw on unrecorded requests
  domainPathRulesMode: 'record_all',  // default 'allowlist' records nothing until you enable paths
});

Since Mockifyer core 1.10.187, local recordings store response bodies only when MOCKIFYER_RECORD_RESPONSES=true (or recordResponses: true) is set.

• How it records: patches fetch, or uses axios interceptors (axios needed useGlobalAxios: true in ESM).
• Where it runs: Node and React Native/Expo (per its docs; we didn’t run React Native).
• Storage format: one JSON file per request in mock-data/<scenario>/; authorization was saved as ***.
• Matching: method + URL, with optional header and query rules.
• Re-record workflow: record into a new scenario, then git diff. Scenarios, hand edits, getCurrentDate() and cross-service request IDs worked.
• Maintenance: core 1.10.190, 2026-10-26; local body-recording default changed in 1.10.187 (2026-10-20). Original record/replay tests were on 1.10.181, 2026-10-15.
• Best for: React Native/Expo and multi-service apps.
• Limits:
  • ~207 weekly downloads, 2 stars, essentially one maintainer.
  • Young (March 2025); CHANGELOG.md stops at 1.4.0.
  • fetch and axios only.
  • Surprising defaults: no recording without record_all; recordings kept using the live API until MOCKIFYER_RECORD_DEFAULT_ALWAYS_USE_REAL_API=false was set; and since 1.10.187, local recordings store empty bodies (responsePending) unless MOCKIFYER_RECORD_RESPONSES=true or recordResponses: true is set.
  • The MCP server isn’t on npm.

See Mockifyer and the React Native mocking guide.

Legacy VCR ports to avoid

VCR (Ruby, 2010) named the “cassette” pattern. Its JS ports have stalled:

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Why Mockifyer exists

Maintainer’s perspective. Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

I started Mockifyer in March 2025 for two problems the recorders above didn’t solve for me.

The first was a React Native app with a backend. I wanted to record the app’s real fetch traffic once, keep it in the repo as one readable JSON file per request, and switch between named scenarios (“checkout error”, “empty state”) without rebuilding. In development, Mockifyer writes recordings to the device and, through a Metro middleware, into the project’s mock-data folder. Release builds can load bundled mocks. The app and a Node backend can also share one store through the optional dashboard proxy, backed by Redis.

The second was logging across several services. When a gateway calls one service, which calls another, I wanted to see the whole chain. Mockifyer assigns an X-Mockifyer-Request-Id to each hop, passes the parent ID and the client “lane” header downstream, and the dashboard can show the trace.

Date control (getCurrentDate()) came from the same apps: recorded data with timestamps needs a fixed “now”.

What it doesn’t try to be: a Node-wide interceptor for every HTTP client, a browser E2E tool, or a mature project with a big community. If you’re in Node only, use nock.back. For browser E2E, use Playwright’s HAR. For a polyglot proxy, use Talkback or WireMock.

Migrating from Polly.js

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*Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

Two things to watch. Polly matches on request order by default (order: true), so check suites where repeated identical calls return different responses. And Polly writes HAR, so your existing recordings can feed MSW handlers (see above).

Which should you choose?

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*Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

If you need recording a backend API as regression tests, not just JS client calls, that’s a different layer than the JS client recorders in this table.

FAQ

Is Polly.js still maintained?

It’s not archived or deprecated, but @pollyjs/core hasn’t had a release since 2023-07-20. The last commit, on 2025-05-31, shipped adapter-fetch 6.0.7.

What is the best alternative to Polly.js?

It depends on where your requests run: nock.back for Node, routeFromHAR for browser E2E, or a proxy (Talkback, WireMock) for any language.

Is there a VCR library for JavaScript / Node.js?

Yes: nock.back, Talkback and Proxay use the cassette pattern. Direct ports (node-vcr, sepia, yakbak) haven’t had a release since 2021.

How do I record and replay HTTP requests in Node.js?

Use nock.back: set a fixtures directory, record once, then run lockdown in CI. It covers fetch, axios and http.

How does nock.back record requests?

It records around your test, writes a JSON fixture on nockDone(), and loads it as interceptors next time. Modes: wild, dryrun (default), record, update, lockdown.

Can MSW record real API responses?

No. Capture the traffic elsewhere and load it into handlers. @mswjs/source’s fromTraffic currently works with MSW 2 only.

What is Mockifyer and who maintains it?

An MIT-licensed record/replay library for fetch and axios in Node and React Native. Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

How do I record API responses in React Native?

Patch fetch in dev builds (Mockifyer does this via Metro) or use a proxy like Talkback. See our React Native guide. Disclosure: Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

Related

Polly.js · Nock · MSW · Playwright · WireMock · Mockoon · Mockifyer* · Mirage JS · MSW vs Nock vs Polly · recording a backend API as regression tests, not just JS client calls · MSW vs Nock · Mocking & test data tools · All comparisons

*Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.

Sources (checked 2026-10-15)

• npm registry (versions, release dates, licences, engines): https://registry.npmjs.org/@pollyjs/core, /nock, /msw, /talkback, /proxay, /test-proxy-recorder, /@sgedda/mockifyer-core (Mockifyer: see disclosure), /@mswjs/source, /@playwright/test, /@mockoon/cli
• npm downloads, 2026-10-06 to 2026-10-12: https://api.npmjs.org/downloads/point/2026-10-06:2026-10-12/{package}
• Polly.JS repo, commits and docs (modes, matchRequestsBy, beforePersist): https://github.com/Netflix/pollyjs · https://netflix.github.io/pollyjs/
• Nock README (Nock Back modes, afterRecord) and v15.0.6 release: https://github.com/nock/nock · https://github.com/nock/nock/releases/tag/v15.0.6
• MSW v3.0.0 release notes: https://github.com/mswjs/msw/releases/tag/v3.0.0 · @mswjs/source: https://github.com/mswjs/source
• Playwright: https://playwright.dev/docs/mock#replaying-from-har · https://playwright.dev/docs/api/class-page#page-route-from-har
• Talkback README: https://github.com/ijpiantanida/talkback
• Proxay README and releases: https://github.com/airtasker/proxay/releases
• test-proxy-recorder docs: https://test-proxy-recorder.dev/docs/getting-started/how-it-works/
• WireMock record and playback: https://wiremock.org/docs/record-playback/ · releases: https://github.com/wiremock/wiremock/releases
• Mockoon auto-mocking and recording: https://mockoon.com/docs/latest/logging-and-recording/auto-mocking-and-recording/
• Mockifyer repo (README, REACT_NATIVE.md, MOCKIFYER_INITIALIZATION.md, multi-service example): https://github.com/sgedda/mockifyer (Mockifyer is built and maintained by Sebastian Gedda, who also runs devxtools.dev.)
• VCR (Ruby): https://github.com/vcr/vcr
• Our runs: Node 22.23.3, 2026-10-15, against a local test API. Versions are listed at the top of this page.