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Hiraeth – AWS Emulator

With the recent changes around Localstack pricing/licensing I've been hunting for alternatives. I decided that it might be a fun experiment to try rolling my own. SQS is a service I use heavily so I chose that as the first service to implement. I have more services planned and in development.A few things I think are cool:4MB Docker Image SizeInstant StartupAWS Sigv4 AuthenticationA little admin UI that can be helpful for development/troubleshootingMost of the SQS API implemented, the rest will soon follow :)

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FL score

62

out of 100

Verdict

VALIDATE

medium confidence

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A lightweight AWS SQS emulator built to replace Localstack after its pricing shift, with plans to expand to other services.

The pain

Developers using AWS locally for testing face two problems: Localstack recently changed its pricing model (moving away from free tier), and existing alternatives are either bloated, slow to start, or incomplete in API coverage. Teams need a fast, reliable way to test SQS-dependent code without hitting AWS.

The gap

Localstack dominates but became expensive. Docker-based alternatives exist but are either unmaintained or lack the full SQS API. No lightweight, actively-developed option exists that combines small image size, instant startup, proper AWS authentication, and a usable admin interface.

Build angle

Start by validating that developers actually switched away from Localstack due to pricing (not just considering it). Build SQS to 95% API completeness first. Then measure: do teams actually adopt this over free tier alternatives or self-hosted Localstack? Only expand to other services if SQS adoption reaches meaningful numbers. The real moat is becoming the default for local AWS development, that requires near-perfect compatibility and zero friction.

Strengths

  • Solves a real problem created by Localstack's pricing change, timing is favorable
  • Technical execution appears solid: 4MB image size and instant startup are genuine advantages over Localstack
  • AWS SigV4 auth implementation shows attention to production-like behavior
  • Admin UI reduces friction for developers debugging queue issues
  • Single-service focus (SQS first) is disciplined and testable

Risks

  • Localstack remains free for many use cases and has massive installed base, switching costs are real even if pricing changed
  • One person maintaining this will struggle to keep API parity as AWS updates SQS
  • No clear monetization path, if it's open source, competing on features alone against a funded company is difficult
  • Market size is unclear: how many teams actually need local SQS testing badly enough to switch tools?
  • Expanding to other services (SNS, DynamoDB, etc.) requires exponential effort; incomplete multi-service support is worse than single-service focus
  • Enterprise teams may stick with Localstack despite cost because it's 'official' and supported

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