LambdaOpenApi v1.0 Released!
We’re excited to announce the official v1.0 release of LambdaOpenApi — now available on NuGet!
LambdaOpenApi grew out of an internal tool we built to support our own production AWS Lambda applications. After using it successfully in real workloads, we refined it, generalized it, and open-sourced it so the broader .NET and Lambda community can benefit from the same streamlined OpenAPI workflow.
What is LambdaOpenApi?
LambdaOpenApi is a lightweight, compile-time OpenAPI generator for AWS Lambda Annotations .NET applications. Define your API with simple C# attributes and get a complete OpenAPI 3.x document at build time — no runtime work, no manual YAML, and no drift.
Install
Using the .NET CLI:
dotnet add package Oproto.Lambda.OpenApi
Or via the NuGet Package Manager:
Install-Package Oproto.Lambda.OpenApi
Key Features
Zero Runtime Overhead
Fully compile-time generation using C# source generators — no reflection, no startup scanning, and no cold-start impact.
Seamless Lambda Annotations Integration
Works directly with AWS Lambda Annotations (HTTP attributes, request/response types, errors, and more).
Strongly Typed API Definitions
Describe your entire API surface using C# attributes. Routes, inputs, outputs, and metadata stay clean and discoverable.
OpenAPI 3.x Compliant
Produces a complete, standards-compliant OpenAPI document your tooling can rely on.
Getting Started
Follow the Getting Started guide on our documentation site to generate your first OpenAPI spec in minutes.
Feedback & Contributions
LambdaOpenApi aims to remain small, stable, and focused — but your feedback helps keep it sharp. If you discover any issues or have suggestions, feel free to open an issue on GitHub.
Thank you for trying out LambdaOpenApi — we hope it makes your Lambda development experience simpler and smoother!