Best Helicone alternatives

LangChain's observability and evaluation platform for LLM applications, tracing every step of a chain or agent run and scoring outputs against test datasets.

Unified API and marketplace for LLMs, routing requests to the best available provider for a given model and handling failover automatically across dozens of providers.

Open-source LLM observability and evaluation platform built on OpenTelemetry, with tracing, datasets, experiments and prompt tooling.

Open-source LLM observability platform for tracing, evaluating, and debugging prompts and agent runs, self-hostable or available as a managed cloud service.

Open-source Python library and proxy server that calls 100+ LLM providers through one OpenAI-compatible interface, with built-in cost tracking and load balancing.

Weights & Biases toolkit for tracing, evaluating and monitoring LLM applications, with automatic call logging and scorers.

Evaluation-first platform for LLM applications, treating prompt and model changes like code changes that need regression tests before shipping.

AI gateway for production LLM apps, combining provider routing and failover with caching, guardrails, and observability in one managed layer.