Devcloud

Introduction Developing cloud-native applications comes with recurring pain points: AWS calls in CI pipelines incur costs, development stops without VPN, and onboarding requires credential setup. DevCloud is a local AWS emulator that solves these problems entirely offline. It achieves 671/699 test cases passing (96%) in boto3 compatibility tests. That number isn’t just a test pass rate — it’s a measure of how precisely the protocol layer replicates AWS behavior. This post explains how a single Go binary achieves this level of compatibility, covering protocol detection, serialization challenges, the plugin architecture, and the path from 96% to production-ready. ...

Introduction AWS provides over 200 services, each with its own API protocol and request/response structure. Manually implementing them one by one is practically impossible. At DevCloud, we built a codegen pipeline that reverse-engineers AWS’s internal modeling language, Smithy, to auto-generate Go code for nearly all AWS services. This post covers the full flow from parsing Smithy models to generating Go code, and how the auto-generated code powers a local AWS emulator. But the more fundamental question is: why generate code from an IDL at all? To understand the value beyond simple “productivity automation,” we need to first understand the problem this approach solves. ...