Respan

Respan (formerly Keywords AI) is an LLM engineering platform that provides self-driving observability, evaluations, and a unified gateway for AI agents. The platform enables AI teams to trace agent behavior with end-to-end execution paths, evaluate using human review, code checks, and LLM judges, and optimize prompts with version tracking for models, tools, and workflows.

The platform routes across 500+ LLM models through a single AI Gateway with real-time dashboards tracking quality, latency, cost, and custom metrics. Processing over 1 billion logs and 2 trillion tokens per month, Respan serves 100+ customers and 6.5 million+ end users. The platform is ISO 27001 certified, SOC 2 compliant, GDPR compliant, and HIPAA compliant with BAA available.

Backed by Y Combinator (W24), Respan achieved profitability on its initial YC funding alone. The company rebranded from Keywords AI to Respan in early 2026, with the name inspired by 'spans' — the atomic units in AI tracing and debugging. The team operates lean from Alameda, California with SDKs for Python and TypeScript.