rinha2-back-end-dotnet

C#/.NET 9 Native AOT implementation for the Rinha de Backend 2024/Q1 challenge with Npgsql multiplexing and PostgreSQL stored procedures

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About

A C#/.NET implementation of the Brazilian backend challenge Rinha de Backend 2024/Q1, where a fictional bank API must handle concurrent transactions under strict resource constraints (1.5 CPU, 550MB RAM total). This implementation uses ASP.NET Core 9 Minimal API with Native AOT compilation for zero-JIT startup, System.Text.Json source generators for reflection-free serialization, and Npgsql multiplexing for high-throughput database access. Achieved a Perfect Score badge with all requests under 800ms at 250MB RAM usage.

Tech Stack

Technology	Version	Purpose
.NET / ASP.NET Core	9.0	Minimal API with Native AOT compilation
Npgsql	10.0.2	PostgreSQL driver with connection pooling and multiplexing
PostgreSQL	-	Database with stored procedures and tuned write settings
Nginx	1.27	Reverse proxy and load balancer (least-conn)
Docker	-	Multi-stage build and orchestration
k6	-	Stress testing

Features

• Native AOT compilation for zero-JIT startup and minimal memory footprint
• System.Text.Json source generators for reflection-free JSON serialization
• Npgsql connection pool with multiplexing for concurrent query throughput
• PostgreSQL stored procedures for server-side business logic
• PostgreSQL tuned with synchronous_commit=0, fsync=0, full_page_writes=0
• Conditional compilation to strip OpenTelemetry in production builds

Getting Started

Prerequisites

• Docker with Docker Compose

Quick Start

git clone https://github.com/jonathanperis/rinha2-back-end-dotnet.git
cd rinha2-back-end-dotnet
docker compose up nginx -d --build

API available at http://localhost:9999

Endpoint	Method	Description
/clientes/{id}/transacoes	POST	Submit debit or credit transaction
/clientes/{id}/extrato	GET	Get account balance statement
/healthz	GET	Health check

Project Structure

rinha2-back-end-dotnet/
├── src/WebApi/
│   ├── Program.cs            — Complete API (route handlers, DI, config)
│   ├── WebApi.csproj         — Project config (AOT, Trim, ExtraOptimize flags)
│   └── Dockerfile            — Multi-stage build
├── docker-entrypoint-initdb.d/
│   └── rinha.dump.sql        — Schema, stored procedures, seed data
├── docker-compose.yml        — Dev stack: API x2, Nginx, PostgreSQL, observability
├── prod/docker-compose.yml   — Prod stack with GHCR images
├── nginx.conf                — Load balancer (least_conn)
├── grafana/                  — Pre-configured dashboards
├── wiki/                     — GitHub Wiki (submodule)
├── docs/                     — GitHub Pages site + k6 reports
└── .github/workflows/        — CI/CD pipelines

CI/CD

Workflow	Trigger	Purpose
Build Check	PRs to main	Build + Docker health check
Main Release	Push to main	Multi-platform Docker push to GHCR + k6 load test
CodeQL	PRs + weekly	Security analysis
Deploy Docs	Push to main + wiki changes	Generate docs site from wiki

Docker image: ghcr.io/jonathanperis/rinha2-back-end-dotnet:latest

License

MIT — see LICENSE