Router
Routing guide
Eligible providers are ranked, then executed in score order with timeouts, fallbacks, and a durable circuit breaker. Bing, Parallel, and Perplexity Sonar are dark: they are excluded from default auto-route unless listed in providers.only or providers.order.
Scoring
Cost and latency are inverted. Freshness, reliability, and quality are 0–1 catalog signals. A sort override collapses the profile (price, latency, throughput, quality, or freshness). providers.order pins try-order ahead of remaining scored candidates.
Engines
| Engine | Cost | Latency | Fresh | Reliability | Quality |
|---|---|---|---|---|---|
| auto | 0.22 | 0.2 | 0.18 | 0.2 | 0.2 |
| cheap | 0.55 | 0.1 | 0.1 | 0.15 | 0.1 |
| fresh | 0.1 | 0.15 | 0.5 | 0.1 | 0.15 |
| fast | 0.08 | 0.5 | 0.1 | 0.2 | 0.12 |
| reliable | 0.08 | 0.12 | 0.1 | 0.5 | 0.2 |
Circuits and rate limits
Three failures in 30 seconds open a 15-second circuit, stored in Redis when configured so Vercel isolates share state. Per-key rate limits emit standard 429 headers. Demo key: 20 rpm / 200 rpd.