Architecture

Simfra is a single Go binary that emulates 88 AWS services on one HTTP port. Unlike API mocks that return canned responses, Simfra maintains real state, enforces IAM policies, performs actual cryptographic operations, and runs real software in Docker containers.

This section explains how Simfra works so you can reason about its behavior, debug issues, and understand where the simulation is faithful to AWS and where it diverges.

Contents

• How Simfra Works - the big picture: single binary, request routing, protocol handling, state model, and IAM enforcement.
• Request Lifecycle - what happens step-by-step when you make an API call, from HTTP request to response.
• Docker Architecture - how Docker-backed services (Lambda, RDS, EC2, etc.) work, including container communication, VPC networking, and credential injection.