Respan

Respan is a web and API LLM engineering platform for AI startups and enterprise engineering teams building and scaling LLM applications and agents.

Key capabilities include:

• End-to-end observability and tracing across prompts, tool calls, responses, routing, memory, and production traffic, with search and filters for latency, cost, quality, tags, and custom metadata
• Debugging and replay of real production sessions in an integrated playground, enabling teams to reproduce failures and test fixes with full context
• Evaluations and testing workflows that combine automated checks, human review, and LLM judges, with versioned datasets created from production traces and comparisons against production baselines using metrics such as accuracy, cost, latency, and safety
• Unified LLM gateway and deployment controls with OpenAI-compatible integration, dynamic routing, load balancing, error handling, and access to 500+ models, plus version control for prompts, tools, models, and routing

Pricing: Pro plan $0/month ( Sign up for free), Team plan $199/month, Enterprise (contact for pricing).

What makes it notable is its closed-loop workflow that connects production tracing, evaluation pipelines, and an adaptive gateway for continuous improvement, plus compliance support (ISO 27001, SOC 2, GDPR, HIPAA) and broad integrations (OpenAI, Anthropic, LangChain, LlamaIndex, Vercel AI SDK, Google Vertex AI).