Langfuse

LangSmith

langchain.com

Popular

LangChain's hosted platform for tracing, evaluating and monitoring LLM apps and agents, framework-agnostic.

Arize Phoenix

Arize-ai/phoenix

Open-source AI observability and evaluation tool built on OpenTelemetry and OpenInference.

Braintrust

braintrust.dev

Rising

Evaluation-first AI platform where production traces become datasets and regression tests.

Promptfoo

promptfoo/promptfoo

Popular

CLI and library for testing prompts, comparing models and red-teaming LLM apps in CI; acquired by OpenAI.

DeepEval

confident-ai/deepeval

Pytest-style framework for unit-testing LLM outputs with research-backed metrics like G-Eval and faithfulness.

Ragas

vibrantlabsai/ragas

Evaluation toolkit for RAG and agent pipelines with metrics such as faithfulness and context recall.

Opik

comet-ml/opik

Comet's open-source platform for tracing, evaluating and optimizing LLM apps and agents.

Helicone

Helicone/helicone

Open-source LLM observability proxy: one-line integration for logging, costs, caching and rate limits.

OpenLLMetry

traceloop/openllmetry

OpenTelemetry instrumentation for LLM providers, vector DBs and frameworks, by Traceloop.