Software Engineer – AWS

LocalStack - the Local Cloud Sandbox for Developers and AI Agents

We are a fast-growing Series A startup building cutting-edge technology to revolutionize cloud development processes and support highly efficient dev&test feedback loops. We’ve closed our last $25mil round in Q4 2024, led by Notable Capital , CRV and Heavybit .

LocalStack is a local cloud development platform. LocalStack makes it easier, faster, and less expensive for software teams to ship reliable, high-quality applications to the cloud.

The cloud was built to run software, not to support AI-native development workflows. As the world's leading local cloud development platform, LocalStack provides secure local sandboxes that simulate cloud environments, enabling AI agents and software developers to find and fix risks faster and more effectively than they can in the cloud.

Our customer base ranges from SMBs to Global Fortune 500 companies. Our clients include companies like NASA, Harness, IBM, Workday, Comcast, Apple, 3M, Block and many more.

We are sustainably growing our globally distributed teams across GTM, operations and engineering. In 2025 we almost doubled in size and continue to grow across all areas in 2026.

LocalStack is headquartered in Zurich/Switzerland 🇨🇭, with a small engineering office in Vienna/Austria 🇦🇹 and remote team members from 25 countries including 🇺🇸the US, 🇫🇷FR, 🇬🇧UK, 🇨🇦CA, 🇪🇸ES, and many more! 👉Check our Notion Candidate Handbook and our GitHub !

✅ About the Role

As a Software Engineer on the AWS Emulator team, you’ll help expand and harden LocalStack’s AWS emulator by taking ownership of individual services and making them behave as closely as possible to real AWS.

The challenge is genuinely unusual: you’ll reimplement cloud services that you can only observe from the outside. Making a service “work” is one thing; matching AWS behaviour — including edge cases and undocumented details — is a very different engineering problem.

We’re looking for someone who learns quickly, enjoys tackling unfamiliar problems, and can turn incomplete information into working solutions. You’ll have end-to-end ownership of your services, from investigating how they behave and deciding what needs to be built through implementation, testing, and ongoing improvements.

AI is a core part of how the team works. You’ll use modern AI coding and agentic tools to make development more efficient while maintaining the quality and reliability expected by LocalStack users. The role offers a clear path to broader service ownership and technical leadership as your scope grows.

✅ What you will be working on/responsible for

Independently take AWS services from third-party-backed implementations to fully first-party implementations, owning store design for persistence, full API operation coverage, and conformance to LocalStack conventions.

Close parity gaps in owned services by raising snapshot-test coverage against real AWS across the documented API surface, with a measurable reduction in parity defects reported from the field.

Own services end-to-end after they ship. Act as a first responder for your services, triaging and resolving customer-reported parity bugs within a 5-day median, including issues that surface through Terraform and CDK rather than direct API calls.

Contribute reusable test infrastructure (conformance harnesses, snapshot tooling, fixtures) that other engineers adopt for services they do not own.

By month 12, be trusted to scope and sequence an a complete implementation of an emulated service independently, from API documentation analysis and experimentation through implementation, testing, and a shipped provider, without needing the plan handed to you.

✅ Experience we expect you to bring to the role

mid-level/senior professional software engineering experience, with strong engineering fundamentals.

Strong programming experience in at least one language. Python is preferred, but we are language-agnostic and value strong engineering fundamentals and the ability to learn new languages quickly.

Experience working from documentation, specifications, public APIs, or observable system behaviour to understand and reproduce how a system works — for example, through APIs, protocols, SDKs, emulators, parsers, or reverse-engineering projects.

A strong testing mindset — you use tests as a tool for understanding and designing systems, not just for checking finished code.

Hands-on experience with AI coding and agentic development. You should have used these tools substantially to build software and understand how to implement guardrails and validate their output, including their strengths and limitations.