Does Keploy replace Jest for Node.js testing?

No. Keploy replaces the integration and API test layer, where nock interceptors and module mocks are costly to maintain. Keep Jest for unit tests of individual modules — Keploy generates the route-level regression suite from real traffic.

Is Keploy a nock alternative for mocking HTTP in Node?

Yes. nock replies with a body written in your test file, so it cannot detect upstream drift. Keploy records the real axios, fetch, and undici responses at the socket layer and replays them, so re-recording refreshes every mock at once.

Can Keploy mock MongoDB calls without mongodb-memory-server?

Yes. Keploy captures the MongoDB wire protocol beneath mongoose and the official driver, so the exact documents your queries returned replay on test runs. CI needs no mongod binary download and no seed step.

Does Keploy work with TypeScript and NestJS?

Yes. Keploy records the running Node process rather than your source, so TypeScript, decorators, and the NestJS dependency injection container are all invisible to capture. Wrap nest start or the compiled entrypoint and record.

Do I need to install Keploy from npm?

No. Keploy is a standalone CLI binary that launches your app as a subprocess, so it never appears in package.json, your lockfile, or your node_modules tree — and it cannot conflict with a package version in your project.

Is Keploy free for Node.js projects?

Yes. The Keploy CLI is open source under Apache 2.0 and free to run on any Node service with no seat limits. Paid cloud plans add hosted test storage, dashboards, and team management on top of the same engine.

Keploy as a Node.js testing framework

Keploy tests Node.js services by recording real HTTP requests and every downstream call they trigger, then replaying both as assertions. There are no nock interceptors to register, no jest.mock factories to maintain, and no in-memory database to seed before a test runs.

Generate Node.js tests free

keploy record -c "npm start"

18.4K+

1.2M+300M+mocks createdSlack

What Keploy gives a Node.js team

Any Node service, unchanged

Keploy wraps your start script. Express, Fastify, NestJS, Koa, and Hapi all record identically, and TypeScript is irrelevant to capture because Keploy records the running process rather than your source.

Node 16 and above, CJS or ESM
No exported app object required
TypeScript needs no extra setup
Full middleware stack executes

Try Keploy for free Explore the docs

The problem

Why Node.js integration tests slow teams down

The friction is rarely the assertions. It is everything around them — spinning up dependencies, keeping mocks honest, and repairing tests after every refactor.

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Three ways to do it

Testing Node.js: by hand, with Jest + nock + supertest, or with Keploy

Every nock interceptor and module mock is a hand-written copy of a contract you do not own. Keploy records the real response, so re-recording refreshes all of them at once.

By hand

Jest + nock + supertest

With Keploy

Select any row for the full comparison, with code.

Get started Book a call

Same coverage, three costs

What you write for Node.js vs what Keploy records

All three produce the same assertion. Only the third still passes after the next refactor without anyone editing it.

By hand2–4 hours

orders.manual.test.js

hand-written

// Hand-written: stubs, payloads, and assertions by hand.

const request = require('supertest');

const buildApp = require('../src/app');

const fakeRepo = {

get: async (id) => ({ id, amountMinor: 4200, state: 'NEW' }),

save: async (order) => order,

};

const fakePayments = {

charge: async () => ({ status: 'AUTHORIZED', id: 'ch_1' }),

};

describe('POST /orders/:id/confirm', () => {

it('confirms an authorized order', async () => {

const app = buildApp({ repo: fakeRepo, payments: fakePayments });

const res = await request(app)

.post('/orders/ord_1/confirm')

.send({ paymentToken: 'tok_123' });

expect(res.status).toBe(200);

expect(res.body.state).toBe('CONFIRMED');

expect(res.body.amountMinor).toBe(4200);

});

Two stub objects exist only for this file, and both hard-code a shape that nothing verifies against the real Mongo document or Stripe response.

Jest + nock + supertest1–2 hours

orders.jest.test.js

tool-assisted

// Jest + nock + supertest + mongodb-memory-server.

const nock = require('nock');

const request = require('supertest');

const { MongoMemoryServer } = require('mongodb-memory-server');

let mongo;

beforeAll(async () => {

mongo = await MongoMemoryServer.create();

await connect(mongo.getUri());

await seedOrders([{ _id: 'ord_1', amountMinor: 4200, state: 'NEW' }]);

});

afterAll(async () => {

await mongo.stop();

nock.cleanAll();

});

it('confirms an authorized order', async () => {

// A literal that will not change when Stripe does.

nock('https://api.payments.example.com')

.post('/v1/payment_intents/tok_123/confirm')

.reply(200, { status: 'AUTHORIZED' });

const res = await request(app)

.post('/orders/ord_1/confirm')

.send({ paymentToken: 'tok_123' });

expect(res.status).toBe(200);

expect(res.body.state).toBe('CONFIRMED');

});

Three libraries, a downloaded mongod binary, and a seed step — and the Stripe body is still a hand-typed literal nobody re-checks.

With Keploy~5 minutes

test-1.yaml

auto-generated

# Recorded with: keploy record -c 'npm start'

# Nobody wrote this file. Keploy captured it from a real request.

version: api.keploy.io/v1beta1

kind: Http

name: test-1

spec:

req:

method: POST

url: /orders/ord_1/confirm

body: '{"paymentToken":"tok_123"}'

resp:

status_code: 200

body:

id: "ord_1"

state: "CONFIRMED"

amountMinor: 4200

confirmedAt: "2026-09-02T11:04:18Z"

noise:

- body.confirmedAt

# No nock, no memory server, no seed step.

mocks:

- kind: Mongo

operation: "orders.findOne({ _id: 'ord_1' })"

- kind: Http

url: https://api.payments.example.com/v1/payment_intents/tok_123/confirm

status: 200

The Mongo document and the Stripe response are recorded from the real dependencies. Re-recording after an upstream change updates both automatically.

Times are estimates for authoring one endpoint’s coverage from scratch, not measurements.

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Keploy vs the alternatives

Node.js testing tools, compared

The options a team on Node.js actually reaches for, and where each one genuinely wins. Select a row for the full comparison.

Keploy

Jest + supertest

nock

Mocha + Sinon

Mock Service Worker

Postman

SmartBear ReadyAPI

Best in classStrongPartialNot covered

Assessments reflect each tool’s documented behaviour, not benchmark measurements.

Request a trial Book a call

How it works

Record your Node.js app once, replay it forever

Keploy sits below your Node.js process at the network layer. It watches the calls your app already makes, then serves them back on replay so tests run with no dependencies attached.

Your Node.js appGET/api/v1/orders/{id}200

RecordingKeploy proxyeBPF · userspace

MongoDBWire protocol under mongoose and the Mongo driver

PostgreSQLPostgres protocol under node-postgres and Prisma

MySQLMySQL protocol under mysql2 and Sequelize

RedisRESP under ioredis and node-redis

+4 more Node.js dependencies

An example shape of a captured call. Your own endpoints and dependencies come from your real traffic, so nothing here has to be written by hand.

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Mock coverage

What Keploy mocks for Node.js, with zero config

7 of the 8 dependencies a typical Node.js service talks to are stubbed from the recording itself — no mock classes, no fixture files, no containers in CI.

Auto-mocked
MongoDBView page
Wire protocol under mongoose and the Mongo driver
Auto-mocked
PostgreSQLView page
Postgres protocol under node-postgres and Prisma
Auto-mocked
MySQLView page
MySQL protocol under mysql2 and Sequelize
Auto-mocked
RedisView page
RESP under ioredis and node-redis
Auto-mocked
Apache KafkaView page
Kafka protocol under kafkajs
Auto-mocked
gRPCView page
HTTP/2 framed calls from @grpc/grpc-js
Outbound HTTP
Auto-mocked
Outbound HTTP
Any axios, undici, fetch, or got call
Partial
Amazon S3
S3 REST API via aws-sdk v3

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Quick start

Your first Node.js test suite in under five minutes

Every command below runs against your existing Node.js service. Nothing in your source tree changes.

1
1Install the Keploy CLI
A standalone binary — not an npm package, so package.json and your lockfile stay untouched.
curl -sSL https://keploy.io/install.sh | bash
2
2Record your service
Hand Keploy the start script you already use. It runs the process and watches every socket it opens.
keploy record -c "npm start"
3
3Exercise your routes
curl, Postman, your frontend, or an existing smoke script. Each request becomes a test case with its mocks attached.
curl -X POST localhost:3000/orders/ord_1/confirm -H 'Content-Type: application/json' -d '{"paymentToken":"tok_123"}'
4
4Replay in CI
Replay serves recorded dependency responses, so no Mongo service or memory server is needed in the runner.
keploy test -c "npm start" --delay 10