LocalStack vs Mock Service Worker

From $39 per licence/month (Base, billed annually; $45 monthly)

Free and open source

Plans are Hobby (free, non-commercial), Base $39 and Ultimate $89 per licence/month billed annually, then Enterprise. Commercial use needs a paid licence, and the higher tiers are what unlock advanced IAM enforcement and the wider service coverage.

Free and open source. You pay in engineering time and CI minutes.

Hobby tier is free but explicitly non-commercial, and LocalStack has said the Community emulator will no longer receive product updates.

Everything, self-hosted

Category standard

LocalStack · since 2017

Category standard

OSS community · since 2020

• Integration tests against AWS services run offline in seconds at no cloud cost.
• Removes the shared-sandbox-account contention that plagues cloud teams.
• Works with Terraform and CDK, so infrastructure code is testable.

• One set of handlers reused across unit, component, E2E and local development.
• Application code is completely unaware it is being mocked — no test-only branches.
• Supports REST and GraphQL with the same model.

• No longer open source: the Community edition is end-of-life, the repo is archived, and running it now requires an account and auth token.
• Using it in CI counts as commercial use, so the free tier does not cover the case most teams want it for.
• Emulation is not identical to AWS; some behaviours and IAM semantics differ.

• JavaScript ecosystem only.
• Service Worker registration adds a setup step and occasional caching confusion.
• Handlers can drift from the real API without contract verification.

AWS-native teams whose tests currently depend on a shared cloud account, and who are willing to pay for a licence now that the free community route has closed.

Front-end teams that want one mocking approach across every kind of test.