OpenRouter

OpenRouter is a routing layer with a marketplace bolted on: one endpoint, 500+ models from dozens of providers, price and latency shown side by side, plus the plumbing that makes model choice reversible — automatic fallback chains when a provider degrades, routing parameters that sort candidates by cost, speed or tool-calling reliability, and provider filters you can pin to policy. Billing runs on prepaid credits, and token rates pass through at the upstream list price: what OpenRouter adds is 5.5% on credit purchases ($0.80 minimum; 5% for crypto), not a per-token markup. Bring-your-own-key works too, prompt logging is off unless you enable it, and providers can be filtered to ones that do not train on inputs.

Where it loses: capacity is not yours. Rate limits belong to the providers behind the router, outages travel through the fallback chain, and vendor-specific features — caching semantics, structured-output dialects, fine-tuning — arrive late or never, so teams leaning on the advanced surface of one lab API often go direct anyway. The contract, the DPA and the model terms sit with the provider, not the router. Pick it if your cost curve depends on swapping checkpoints weekly, or if you need a fallback rather than a hero model. Check the credit fee against your volume, the throughput your tier gets per provider, and what happens when a slug is deprecated.