AWSim

A fully offline, free AWS development environment. Single binary, sub-second startup, 60+ services, real IAM policy enforcement, and an estimated-bill dashboard so you can watch how much your workload would cost on real AWS.

Quick Start

Docker

docker run --rm -p 4566:4566 -v awsim-data:/data ghcr.io/qaidvoid/awsim:latest

Multi-arch images (linux/amd64, linux/arm64), plus :nightly for the latest main. Admin UI at http://localhost:4566/_awsim/ui/. See docs/guide/docker.md for compose, env vars, and persistence.

For a publicly-trusted HTTPS endpoint with zero client-side trust setup, publish port 4567 and turn the listener on:

docker run --rm -p 4566:4566 -p 4567:4567 -v awsim-data:/data \
  -e AWSIM_HTTPS_PORT=4567 \
  ghcr.io/qaidvoid/awsim:latest

https://aws.qaidvoid.dev:4567 resolves to your loopback (DNS A record pinned to 127.0.0.1) and serves a real Let's Encrypt cert browsers / SDKs already trust. See docs/guide/tls.md for the LocalStack-style story.

From source

cargo run -- --port 4566

Usage

Configure any AWS SDK to point to AWSim:

export AWS_ENDPOINT_URL=http://localhost:4566
export AWS_ACCESS_KEY_ID=test
export AWS_SECRET_ACCESS_KEY=test
export AWS_DEFAULT_REGION=us-east-1

aws s3 mb s3://my-bucket
aws sqs create-queue --queue-name my-queue
aws dynamodb create-table --table-name my-table \
    --key-schema AttributeName=id,KeyType=HASH \
    --attribute-definitions AttributeName=id,AttributeType=S \
    --billing-mode PAY_PER_REQUEST

Supported services

All services share the same http://localhost:4566 endpoint; routing comes from the X-Amz-Target header (JSON protocols), the URL path (REST), or the Action= form field (Query). See docs/services/ for the full per-service operation lists.

Highlights

• DynamoDB on SQLite. Items live in a single WAL-mode SQLite database ({data_dir}/dynamodb.db) — bounded memory regardless of row count, real ACID TransactWriteItems, and an awsim-only TruncateTable op for fast resets. See docs/services/dynamodb.md.
• Real IAM policy enforcement. Opt-in via AWSIM_IAM_ENFORCE=true. Implements identity policies, resource policies, permissions boundaries, SCPs, and session policies with all 26 condition operators. Currently enforced on S3, DynamoDB, KMS, SQS, SNS, Secrets Manager, Lambda, and IAM. See docs/guide/iam-enforcement.md.
• Lambda execution. Real container-based Lambda runtimes (Node, Python, Go, Rust) via docker run. Supports event source mappings from SQS, Kinesis, and DynamoDB Streams. See docs/guide/lambda-execution.md.
• Persistence. --data-dir enables snapshot-based recovery for tables, queues, secrets, IAM, etc. Object/message/code/layer bodies are written to per-service body stores; orphan GC sweeps them on startup. See docs/guide/persistence.md.
• Admin console. SvelteKit UI at http://localhost:5173 (after cd ui && bun run dev) — browse buckets, scan DynamoDB, invoke Lambda, list IAM principals, etc. See docs/guide/admin-console.md.
• Estimated billing dashboard. Real-time rolling AWS bill at /billing — every metered request × vendored AWS pricing, with per-service breakdown, 30-min cost trajectory chart, and a "time to bankruptcy" widget. Pricing data is pulled directly from the AWS Pricing Bulk JSON via cargo run -p awsim-billing --bin refresh-pricing --features refresh. Covers per-request, byte-ingest, data-transfer, GB-month storage, GB-second compute, instance-hours, state-transition and per-character billing axes across 25+ services. See docs/guide/billing.md.
• Chaos engine. Inject synthetic AWS errors and latency on a per-service / per-operation basis to test retry, backoff, circuit-breaker and graceful-degradation logic. Drive it from the /chaos dashboard, the awsim chaos CLI, or the /_awsim/chaos/* HTTP API. Six built-in presets (flaky-s3, ddb-throttle, slow-lambda, kms-outage, regional-failover, network-jitter) cover the common scenarios. See docs/guide/chaos.md.

Configuration

Admin console

cd ui && bun run dev

Open http://localhost:5173.

Documentation

• What is AWSim
• Getting started
• Configuration
• Persistence
• IAM enforcement
• Lambda execution
• API Gateway
• Cognito OAuth
• Estimated billing
• Service-by-service operation lists

License

MIT OR Apache-2.0