Helicone

Helicone is an open-source platform for AI engineers that combines LLM observability with an AI gateway. It records the requests your application sends to model providers so you can trace agents, chatbots and document-processing pipelines, debug sessions, and see how much each call costs and how long it takes.

Integration is meant to be quick: a single line of code can log requests made through OpenAI, Anthropic, LangChain, Gemini, the Vercel AI SDK and similar tools. The gateway side offers access to many models through the OpenAI API format, with intelligent routing and automatic fallbacks. Other features listed in the README and repository topics include cost and latency tracking, datasets and fine-tuning support, prompt management, evaluation and a playground.

Helicone is licensed under Apache-2.0 and written in TypeScript. It can be self-hosted, and the vendor also runs a hosted cloud version. It suits teams that want visibility into LLM spend and quality without building their own logging pipeline.