LocalStack is a local cloud emulator that lets you develop and test AWS applications entirely on your machine or in CI, without touching your live cloud account. By mirroring real AWS behavior in a single Docker container and pairing it with developer tools like the awslocal CLI, LocalStack shortens feedback loops, cuts costs, and makes cloud workflows far more predictable for teams of all sizes.
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💻 A fully functional local AWS cloud stack. Develop and test your cloud & Serverless apps offlineThe friction of real cloud development
Modern cloud apps depend on dozens of managed services. Spinning those up to validate a change can be slow, expensive, and noisy. Waiting for IAM policies to propagate, debugging network edge cases, and managing per-developer sandboxes all create drag. In CI, these problems multiply: ephemeral accounts, quotas, and intermittent network failures derail otherwise routine tests. Teams needed a safe, fast, and reproducible way to iterate on cloud code locally before ever deploying to a real account.
A local AWS in one container
LocalStack answers this with a fully functional local AWS cloud that runs on your laptop or CI runner. Start the stack, point your SDKs and tools at the LocalStack endpoints, and iterate. It supports a broad catalog of AWS APIs; Lambda, S3, DynamoDB, SQS, SNS, API Gateway, CloudFormation, and many more so you can build serverless backends, event-driven pipelines, or infrastructure-as-code (IaC) templates without provisioning anything in a live AWS account.
Key features that matter in practice
Out of the box, LocalStack focuses on developer ergonomics while maintaining realistic behavior that catches integration issues early. Here are the core capabilities developers rely on every day.
- Broad AWS API coverage: Emulates popular services including S3, Lambda, DynamoDB, SQS, SNS, API Gateway, CloudFormation, and more. See feature coverage for details.
- Simple startup and status: A lightweight CLI manages the Docker runtime:
localstack start -d,localstack status services, andlocalstack stop.- awslocal CLI: A drop-in wrapper around the AWS CLI that targets LocalStack endpoints automatically. Docs: awslocal.
- Friendly with IaC and frameworks: Works with Terraform, AWS CDK, Serverless Framework, and more so you can validate stacks before deployment.
- Local-first developer experience: No real cloud credentials needed for everyday dev and tests. Great for CI where determinism and isolation matter most.
- Pro enhancements when you need them: Features like Cloud Pods (state persistence and sharing), Stack Insights, and Ephemeral Instances are available in paid tiers. See Licensing & Tiers.
- Integrations and tooling: Optional UI via the web app, Desktop app, and Docker extension; rich docs and examples to onboard quickly.
These features are organized in a well-structured repository. The top-level README.md provides install and quickstart guidance; docker-compose.yml and the Dockerfile define container behavior; docs/ contains contributor and development references; and pyproject.toml anchors the Python packaging configuration.
Under the hood: practical engineering
LocalStack is primarily a Python codebase orchestrated through Docker. The service front door exposes AWS-compatible endpoints on a single edge port (commonly 4566) so SDKs and CLIs can connect without bespoke configuration. Internally, modules simulate the behavior of AWS APIs and resources, while background processes handle eventing and state. The repository layout surfaces this separation of concerns: localstack-core/ provides core runtime logic, with supporting scripts in bin/ and scripts/, and extensive validations in tests/.
You can run the stack in multiple ways to match your environment: directly via the LocalStack CLI, with plain Docker, using Docker Compose, or deploying into Kubernetes via Helm. This flexibility is documented in the README sections for Running and Usage, and in the official LocalStack docs.
# Install the CLI (Python package)
python -m pip install localstack
# Start LocalStack in the background
localstack start -d
# Check service availability
localstack status services
# Use AWS services locally with awslocal (example: SQS)
awslocal sqs create-queue --queue-name sample-queue
Where teams use it: real-world scenarios
LocalStack shines when you need high-fidelity integration feedback without provisioning real infrastructure. Serverless teams iterate on Lambda + API Gateway flows locally, validating event payloads, error paths, timeouts, and retries before deploy.Â
Data engineers prototype S3-triggered ETL with DynamoDB, SQS, and Step Functions to verify handoffs and idempotency. Platform teams test Terraform or AWS CDK templates end-to-end to catch breaking changes in resource graphs early. In CI, suites run deterministically against LocalStack, eliminating race conditions and noisy neighbors from shared cloud accounts.
Common patterns include: validating S3 lifecycle and ACL behavior for storage-heavy apps; load testing SQS/SNS fan-out pipelines before scaling; testing Kinesis and streaming consumers with backpressure; rehearsing IAM permission boundaries and trust relationships without risking production accounts; and verifying CloudFormation or CDK stack updates to ensure resource replacements happen as expected. For hands-on starters, the official Sample Apps and Tutorials provide runnable blueprints.
Why it matters to the community
LocalStack reduces the cost of learning and building on AWS. New contributors can clone a repo, start LocalStack, and run the full system locally, no cloud account, quotas, or billing risk. That shortens onboarding and makes open-source projects with cloud backends far more approachable. For maintainers, reproducible bug reports become simpler: capture a minimal failing scenario against LocalStack and share it with the exact versions used.
The project also strengthens CI reliability. When integration tests run against a local emulator instead of a shared staging account, flaky tests drop and build times stabilize. Teams can gate merges on realistic checks that are fast enough to run per-commit, not just nightly. Educational programs benefit as well: instructors can teach AWS concepts in controlled environments without per-student cloud setups. And because the core is open source under Apache 2.0, improvements flow back to everyone.
Community, contributions, and governance
LocalStack has an active open-source community with hundreds of contributors and frequent releases. If you want to help, start with docs/CONTRIBUTING.md and the development environment setup. Issues and discussions happen in the issue tracker, while the team runs an active Slack community for support and collaboration. The project uses modern Python tooling (Black, Ruff) and CI, documented in the repository badges and workflows.
Usage & license terms
The core repository is released under the Apache License, Version 2.0. See LICENSE.txt for the legal text. In addition, the project notes an End-User License Agreement (EULA) in docs/end_user_license_agreement. Practically, Apache 2.0 permits use, modification, and distribution, commercial or otherwise, provided you include the license and notices and comply with its terms.
Beyond the open-source core, LocalStack offers paid tiers with additional features and hosted capabilities. The current tiers, Free, Base, Ultimate, and Enterprise are outlined in the official Licensing & Tiers page, which also explains usage allocations for CI credits, Ephemeral Instance minutes, and Cloud Pods storage.
Impact and what comes next
LocalStack has become a standard part of the toolbox for teams practicing cloud-native development. By moving integration feedback from minutes to seconds and removing the risk of testing in a shared AWS account, it speeds up delivery while improving reliability.Â
The project’s evolution like the recent 4.x releases and continued service coverage, suggests even tighter loops between local dev, CI, and production. Expect deeper IaC integrations, richer state management for complex stacks, and more robust parity for advanced AWS APIs. With tens of thousands of GitHub stars and broad ecosystem adoption, LocalStack’s trajectory looks strong.
Wrap-up: try it locally, ship with confidence
If you build on AWS, running a local cloud is the simplest way to move faster and break less. Explore the LocalStack repository, skim the Quickstart, and point your next feature or test suite at LocalStack. Whether you stick with the Apache-licensed core or add Pro features later, you’ll gain a safer, cheaper, and more reliable path from commit to production.
Explore the repository and join the community:
https://github.com/localstack/localstack
LocalStack: Building AWS Apps Locally Without the Cloud