Can Keploy replace LocalStack?

For testing, Keploy can mock AWS service calls captured during traffic recording, eliminating the need for LocalStack in CI. For local development, LocalStack provides value that Keploy does not — a live AWS-compatible environment for interactive development.

Which tool is better for testing AWS Lambda functions?

LocalStack is better for testing Lambda functions specifically, as it runs your Lambda code locally with realistic AWS event triggers. Keploy tests the API layer that invokes Lambdas but does not emulate Lambda execution itself.

Can I use both Keploy and LocalStack?

Yes. Use LocalStack during development for a local AWS environment, and use Keploy during traffic capture for generating test suites. In CI, Keploy's auto-generated mocks eliminate the need for LocalStack, making tests faster.

Which tool has better AWS service coverage?

LocalStack emulates 80+ AWS services with varying fidelity levels. Keploy does not emulate AWS services — it mocks the responses your application received from them. LocalStack is the clear choice if you need to test AWS-specific behavior.

Which tool is more popular?

LocalStack has 57K+ GitHub stars and very broad adoption for AWS development. Keploy has 20K+ stars and focuses specifically on API test generation. They serve different purposes: LocalStack for AWS emulation, Keploy for automated API testing.

Try Keploy with Claude

Keploy

LocalStack

What LocalStack Can’t Test, Keploy Cancatch what breaks

Local AWS Cloud Emulator

Keploy auto-generates API tests from real traffic using eBPF with zero code changes, while LocalStack emulates AWS cloud services locally for development and testing. Keploy captures and replays API behavior with auto-generated mocks, whereas LocalStack provides local AWS service instances like S3, Lambda, and DynamoDB.

Try Keploy Free Read the Docs

18.4K+

GitHub Stars

1.2M+

Installs

Zero

Code Changes

Apache 2.0

Open Source License

eBPF · zero code changes

How Keploy turns real traffic into a test suite

One pipeline, running the moment your app receives a request. No SDKs, no sidecars, no test scripts — just kernel-level capture that becomes deterministic regression coverage.

01
Real API traffic
Live requests + responses from your running app
02
eBPF capture
Kernel-level recording — zero code changes
03
Normalize
Time-freeze + field noise removed automatically
04
Generate tests
Deterministic test cases from actual behavior
05
Generate mocks
Every downstream dependency stubbed for you
06
Replay in CI
Runs locally, in CI, or in-cluster on Kubernetes
07
Regression detection
Diffs flagged before they reach production

See how the capture-replay engine works under the hood.

Star on GitHub Read the docs

Trusted by engineering teams at scale

Globality

IdeyaLabs

Globality

IdeyaLabs

Globality

IdeyaLabs

Globality

IdeyaLabs

Why teams switch from LocalStack

Keploy eliminates manual test authoring by generating tests automatically from real traffic — no scripts, no stubs, no infrastructure setup.

You want auto-generated tests from real production traffic patterns

Your team needs tests for APIs beyond just AWS service interactions

You prefer lightweight mocks over running a full AWS emulator

The numbers behind the switch

Industry data on how much manual testing costs teams — and what Keploy delivers from the first recording session.

The cost of manual testing

Engineering time on toil

Writing tests, configuring mocks, debugging flakiness — not building features that ship.

Tests break on next refactor

A routine rename or interface change silently invalidates more than half your suite.

What Keploy delivers

Coverage from first recording

Keploy generates tests from every request your API actually handles — no guessing.

Production paths covered

Traffic capture reaches edge cases, error paths, and concurrent requests no dev would write.

Pain stats sourced from developer productivity surveys. Coverage stats from Keploy production recording sessions across 50+ engineering teams.

Every number here comes from teams running Keploy in CI.

Explore Keploy Read the docs

Zero code. Real tests. Automatically.

Keploy's eBPF agent intercepts every API call at the kernel level and turns live traffic into test cases with dependency mocks — no SDK, no sidecars, no annotations.

your-service — running on :3000live

Incoming API Requests

GET/users/list

POST/orders/create

PUT/users/42

DELETE/sessions/7

GET/products

+42 more…

eBPF Kernel Intercept Layer

intercepts all syscalls · no code changes · zero runtime overhead

HTTP/1.1HTTP/2gRPCWebSocketTCP/IP

Keploy Agentrecording · analyzing · generating

Test Cases

testcase-1.yaml

testcase-2.yaml

testcase-3.yaml

…+42 generated

Mock Files

mock-postgres.yaml

mock-redis.yaml

mock-s3.yaml

all deps covered

Every API call your app makes gets captured, replayed as a test, and its dependencies auto-mocked — continuously, from real traffic.

Start recording traffic See setup docs

How they compare, dimension by dimension

A logical breakdown across the dimensions that matter. Click any row for real-world KPI impact across industries.

Key differences at a glance

Test Generation Method

Keploy

Auto-generates from real API traffic via eBPF

LocalStack

Not a test generator — emulates AWS services

Code Changes Required

Keploy

Zero code changes needed

LocalStack

Change AWS endpoint URLs to LocalStack

Mock/Stub Generation

Keploy

Auto-generates mocks for all dependencies

LocalStack

Emulates real AWS services, not mocks

CI/CD Integration

Keploy

Native CLI and Docker support in CI

LocalStack

Docker-based, works in any CI with Docker

Language Support

Keploy

Go, Java, Node.js, Python and more

LocalStack

Language-agnostic via AWS API compatibility

Open Source

Keploy

Apache 2.0, fully open source, 20K+ stars

LocalStack

Open source community edition, 57K+ stars

Dimension

Keploy

LocalStack

Comparison

Click any dimension to see real-world KPI impact across industries.

Dive into how each capability actually works.

Read the docs Star on GitHub

Your tests miss more than you think

Manual tests cover paths developers remember to write — usually just the happy path. Keploy captures every pattern production traffic actually generates.

Manual with LocalStack

tested

not tested

Happy path

Auth error

Invalid input

Not found

DB timeout

Rate limit

Concurrent

Large payload

Edge case

Empty result

GET /users

POST /users

GET /orders

POST /orders

PUT /products

DELETE /sessions

GET /analytics

POST /payments

16%

Production path coverage

84% of real production scenarios go untested

16%

With Keploy

traffic-captured

tested

not tested

Happy path

Auth error

Invalid input

Not found

DB timeout

Rate limit

Concurrent

Large payload

Edge case

Empty result

GET /users

POST /users

GET /orders

POST /orders

PUT /products

DELETE /sessions

GET /analytics

POST /payments

95%

Production path coverage

Auto-captured from real traffic — no code changes needed

95%

Coverage grid shows 8 common endpoints × 10 production scenario types. Manual tests cover only what developers remember to write. Keploy captures every pattern your API actually serves in production.

Keploy is open source — read the code that captures this coverage.

Star on GitHub Explore Keploy

The infrastructure you're maintaining

Traditional testing stacks require a shadow infrastructure to exist alongside your real app. Keploy eliminates all of it — tests and mocks come from actual traffic, not from services you run and maintain.

With LocalStack

Your Appproduction code

Requires all of these ↓

Test Database

postgres-test-instance

Mock Server

WireMock / MSW

Redis Test Instance

separate container

S3 / Object Store

localstack / fake-s3

Test Config Files

env vars, secrets, fixtures

CI Test Runner

spins up all of the above

Infrastructure overhead6+ services

With Keploy

Your Appsame code, unchanged

Only this ↓

Your Real App

no changes needed

Keploy Agent

eBPF — zero overhead

Tests.yaml

Mocks.yaml

CI runpasses

Infrastructure overhead0 extra services

Services to provision

6+0

Config files to maintain

~120

CI spin-up overhead

3–5 min~10 sec

Eliminate test infrastructure See how it works

How they work differently

Architectural differences that affect workflow, cost, and velocity.

KeployeBPF-based

Keploy captures real API traffic and generates integration tests with auto-mocked dependencies, including AWS service calls. Tests are based on actual production behavior and run without any cloud infrastructure or emulation.

eBPF CaptureZero Code ChangesAuto MocksAI Noise DetectionCI/CD Native

LocalStackits approach

LocalStack provides a local emulator for 80+ AWS services. Developers run LocalStack instead of connecting to real AWS, reducing costs and enabling offline development. It emulates S3, Lambda, DynamoDB, SQS, and other services with high fidelity.

Manual configuration

When to use each tool

Specific scenarios where each tool delivers the most value.

Keploy is the better fit when…

You want auto-generated tests from real production traffic patterns
Your team needs tests for APIs beyond just AWS service interactions
You prefer lightweight mocks over running a full AWS emulator
You want zero-code-change setup without configuring emulated services
You need fast CI tests without AWS emulation startup overhead

LocalStack is the better fit when…

You need a local AWS environment for development and debugging
Your application heavily depends on specific AWS service behavior
You want to develop offline without AWS account access
Your team needs to test AWS-specific features like IAM or Lambda
You need high-fidelity AWS emulation for infrastructure testing

Compare the full workflow for your own stack.

Explore Keploy Read the docs

The workflow you're escaping

Same starting point, same finish line. One path is short because Keploy does the tedious middle for you — the other is where teams lose days every sprint.

Without Keploy (LocalStack / manual)

Every dependency is your problem, and every code change ripples back through the test suite you hand-built.

Write API

Write tests

Maintain mocks

Fix flaky tests

Chase non-determinism

Re-write on every change

Deploy

Steps to production7

With Keploy

Record once from real traffic, replay anywhere. Tests and mocks are generated and stay in sync automatically.

Write API

Record traffic

Replay

Deploy

Steps to production4

4 vs 7

Fewer steps between writing code and shipping it

Teams that switch from LocalStack to Keploy delete the entire maintenance middle — test authoring, mock upkeep, and flake chasing.

Cut the maintenance middle out of your test suite.

Read the docs Star on GitHub

The test maintenance trap

With LocalStack, every feature commit generates a hidden tax — a follow-up "fix tests" commit. The commit history tells the whole story.

With LocalStack

— your git log

git log --oneline

a1b2c3feat: add user auth endpoint

3 failing3 days ago

d4e5f6fix: update auth mocks & fixtures

passing3 days ago

g7h8i9feat: payment integration API

7 failing5 days ago

j1k2l3fix: mock timestamps & snapshots

passing5 days ago

m4n5o6feat: analytics dashboard endpoint

5 failing1 week ago

p7q8r9fix: update API response schemas

passing1 week ago

r1s2t3feat: notification service

4 failing2 weeks ago

u4v5w6fix: mock mailer & queue stubs

passing2 weeks ago

↑ Pattern detected: every feature commit breaks tests — 4 of 8 commits are just fixing tests

Commits wasted on test maintenance4/8

With Keploy

— your git log

git log --onelinekeploy active

a1b2c3feat: add user auth endpoint

passing+5 tests3 days ago

g7h8i9feat: payment integration API

passing+12 tests5 days ago

m4n5o6feat: analytics dashboard endpoint

passing+8 tests1 week ago

r1s2t3feat: notification service

passing+6 tests2 weeks ago

↑ Pattern: every feature commit auto-generates tests — 4/4 commits ship features

Feature commits that go straight to CI green4/4

"Fix tests" commits

4 per sprint0

Days spent on mocks

2–3 dayszero

Tests auto-generated

031+

Deterministic replays, no flaky tests — see how.

Star on GitHub Read the docs

Switch from LocalStack in minutes

Choose the path that fits your workflow. Both are up and running the same day.

Integration Testing

via eBPF + CLI · no code changes

Install, record real API traffic, then replay it as regression tests — zero code changes, zero framework dependencies.

~/terminal

1# 1. Install

2curl --silent -O https://keploy.io/install.sh && source install.sh

4# 2. Record your traffic

5keploy record -c "your-start-command"

7# 3. Replay as tests

8keploy test -c "your-start-command" --delay 10

API Testing

via Web UI · no install needed

Paste your cURLs, drop in an OpenAPI spec or Postman collection, and click Generate. Keploy builds your test suite in seconds.

1Go to app.keploy.io

2Paste your cURLs

3Add your schema — OpenAPI, Postman collection, or raw cURLs

4Click Generate — done

Open app.keploy.io

Most teams are generating tests within minutes

No code changes. No framework migration. No staging dependencies.

Get started free Read the docs

18.4K+

GitHub Stars

1.2M+

Installs

Code Changes Required

Apache 2.0

Open Source License

Real-world scenarios

How Keploy handles the challenges your team actually faces.

AWS Integration Testing

With Keploy

Keploy captures calls to AWS services during traffic recording and replays them as mocked responses. No LocalStack or AWS access needed during test execution. Fast and lightweight.

Without Keploy

LocalStack provides real AWS service emulation. Tests interact with actual S3 buckets, DynamoDB tables, and Lambda functions running locally. Higher fidelity but more infrastructure overhead.

Local Development

With Keploy

Keploy is a testing tool and does not provide a development environment. For local development with AWS services, you would need LocalStack or similar tooling alongside Keploy.

Without Keploy

LocalStack excels as a local development environment. Developers work against local AWS services without internet access or AWS costs. Hot-reload and fast iteration on AWS-dependent features.

Join the teams shipping with confidence on Keploy.

Explore Keploy Read the docs

What you write vs what Keploy writes

The same test coverage — one approach takes hours of setup and ongoing maintenance, the other takes five minutes and zero boilerplate.

Manual with LocalStack~35 lines you write & maintain

users.test.js

hand-written39 lines

1// users.test.js — written manually

2import request from 'supertest';

3import app from '../app';

4import { setupTestDB, teardownTestDB } from './helpers';

5import { mockRedis, mockS3, mockMailer } from './mocks';

7let db;

9beforeEach(async () => {

10 db = await setupTestDB();

11 await mockRedis.connect();

12 await mockS3.setup({ bucket: 'test-uploads' });

13 await mockMailer.start();

14 jest.useFakeTimers();

15 jest.setSystemTime(new Date('2024-01-15T10:00:00Z'));

16});

18afterEach(async () => {

19 await db.cleanup();

20 await mockRedis.disconnect();

21 await mockS3.teardown();

22 await mockMailer.stop();

23 jest.useRealTimers();

24});

26describe('GET /users/list', () => {

27 it('returns paginated users', async () => {

28 await db.seed('users', testData.users);

29 const res = await request(app)

30 .get('/users/list?page=1&limit=10')

31 .set('Authorization', `Bearer ${testToken}`);

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

33 expect(res.body.data.length).toBe(10);

34 expect(res.body.data[0]).toMatchObject({

35 id: expect.any(String),

36 createdAt: expect.any(String),

37 });

38 });

39});

Every new endpoint needs a new file. Every refactor breaks tests. Every non-deterministic value (timestamps, IDs) needs custom handling.

Auto-generated by Keploy~27 lines, zero effort

test-1.yaml

auto-generated27 lines

1# test-1.yaml — auto-generated by Keploy

2version: api.keploy.io/v1beta1

3kind: Http

4name: test-1

5spec:

6 metadata:

7 name: test-1

8 type: GET

9 req:

10 method: GET

11 url: /users/list?page=1&limit=10

12 header:

13 Authorization: Bearer <captured>

14 resp:

15 status_code: 200

16 body:

17 data:

18 - id: "usr_abc123"

19 email: "alice@example.com"

20 createdAt: "2024-01-15T10:00:00Z"

21 pagination:

22 page: 1

23 total: 47

24 noise:

25 - body.data.[].id

26 - body.data.[].createdAt

27 - header.X-Request-Id

Keploy captures the real request, response, and all dependency calls. Non-deterministic fields are auto-detected and excluded from assertions.

Lines of test code

per endpoint

~39+

~27

Setup time

initial run

3–4 hrs

5 min

Maintenance

Keploy self-updates

Every PR

Zero

Generate tests automatically See the docs

Frequently asked questions

Common questions about choosing between Keploy and LocalStack.

Still have questions? The docs and community can help.

Read the docs Star on GitHub

Looking for a LocalStack alternative?

Engineering teams evaluating LocalStack alternatives often compare it with Keploy for API testing and regression coverage. Keploy captures real production traffic via eBPF and auto-generates tests with dependency mocks — requiring zero code changes. The key differences come down to how tests are generated (traffic-based vs manual), how dependencies are mocked (automatic vs configured), and what infrastructure changes are needed (none vs SDK/sidecar/containers).

LocalStack alternativeLocalStack vs Keploybest alternative to LocalStackcompare LocalStack and KeployLocalStack open source alternativeswitch from LocalStack

Ready to stop writing tests manually?

Keploy captures your real API traffic and turns it into a regression suite automatically. Zero code changes. Full coverage from day one.

Try Keploy Free Read the Docs