Building an AI Gateway in Rust (Authentication, Rate Limiting, and Routing)

Problem Apps calling OpenAI directly lack control over traffic Solution A gateway layer between the app and AI provider. Real-World Use Cases An AI gateway like this can be useful in several scenarios: 1. Protecting AI APIs Applications calling OpenAI directly may expose API keys or allow uncontrolled usage. A gateway adds a control layer for authentication and rate limiting. 2. Managing API usage Teams running multiple AI features can enforce request limits and monitor usage through the gateway. 3. Centralizing AI traffic Instead of every service calling OpenAI directly, requests pass through a single gateway where traffic policies can be applied. 4. Observability The gateway provides metrics and request logs, making it easier to monitor how AI APIs are being used. Architecture diagram Client Application | v +----------------------+ | AI Gateway | |----------------------| | API Key Auth | | Rate Limiting | | Load Balancer | | Health Checks | | Metrics + Logging | +----------+---------