Respan AI Gateway and Observability

Respan, formerly Keywords AI, is an AI router with built-in observability and automated evals for AI agents. The legal entity is Keywords AI Inc., registered in California per its Terms of Use; the About page says the team joined Y Combinator Winter 2024 and describes a 10-person team.

A gateway routes calls to 1,000+ models through one API with fallbacks, caching, budgets and rate limits. On top of it, tracing captures each LLM call, tool run and retrieval as a span, while evals score outputs with LLM judges, code checks or human review. Named customers include AlphaSense, Retell AI, Gumloop and Lovable.

• Gateway: one endpoint for 1,000+ models with fallbacks, caching, budgets and rate limits.
• Tracing: spans for each LLM call, tool run and retrieval with cost and latency.
• Evals: LLM judge, code checks or human review on test sets from production traffic.
• Monitoring: dashboards for requests, errors, cost and tokens with Slack, email and webhook alerts.
• Guardrails: guardrails offered free with the Respan gateway.
• Open-source gateway: self-hosted gateway, labelled pre-alpha in the docs.

A Vietnamese customer-support software vendor can trace every agent step and score answers with LLM judges. A fintech can route requests to the cheapest model that passes quality checks. A voice-AI startup can alert on error spikes through Slack.

One gateway and one observability layer replace separate routing and tracing tools. Fallbacks and caching improve uptime and reduce spend. Evals built from production traffic catch regressions in agents. The site lists ISO 27001, SOC 2, GDPR and HIPAA, with a BAA available.

AI agents in production create multi-step, multi-model traffic that needs routing, tracing and evaluation in one place. Teams are consolidating gateway and observability tools to cut cost and complexity. Vietnamese and ASEAN startups building agent products can adopt the same pattern with a hosted option.

Formerly Keywords AI; footer reads Keywords AI Inc. Registered in California (Alameda address in Terms of Use). Backers named on About page include Y Combinator, Gradient and Hat-Trick Capital. Launch Week ran 2026-04-20 to 2026-04-24.