ReqKey

ReqKey adds API key authentication, usage credits, rate limiting and request analytics to an API you own. Your middleware makes one verify call per request: ReqKey validates the caller’s key, deducts a credit from that consumer’s pool, enforces their rate limit, and logs the request with status, latency and location. It never sits in front of your API — no proxy, no gateway, no DNS change. Validation averages under 5ms. Credits pool per consumer rather than per key, so issuing a customer a second key doesn’t hand them a second quota. SDKs for Python, Node.js, Go, Rust, PHP, .NET and Java. Free tier: 100,000 requests a month, no credit card.