Respan
LLM tracing, evals, and gateway
The top alternatives to Langfuse in the Observability, Prompts & Evals space, compared on features, pricing, and what they're best at.
Langfuse is an open-source LLM engineering platform that provides comprehensive tools for traces, evaluations, prompt management, and metrics to debug and improve LLM applications. Founded in Berlin, Germany in 2022, Langfuse quickly became a leading platform in the LLM observability space. The platform features MIT-licensed open-source core with no usage limits for commercial use, making it highly accessible to teams of all sizes. Langfuse offers deep integration with popular frameworks including LangChain, OpenAI, LlamaIndex, and LiteLLM. The platform provides detailed tracing capabilities, evaluation tools, comprehensive prompt management, and rich metrics tracking. In January 2026, Langfuse was acquired by ClickHouse, Inc., marking a significant transatlantic venture exit and validating the platform's technology and market position. The acquisition demonstrates the value of Langfuse's approach to LLM observability, evaluations, and prompt management.
Respan
LLM tracing, evals, and gateway
LangSmith
Trace visualization for LLM chains
MLflow
OpenTelemetry-native tracing
Weights & Biases
ML experiment tracking
Arize AI
ML observability with LLM support
Traceloop
OpenTelemetry
Datadog LLM
LLM monitoring within Datadog platform
Helicone
Braintrust
Real-time LLM logging and tracing
HoneyHive
Prompt management
Phoenix
OpenTelemetry-based LLM and agent tracing
Patronus AI
Automated LLM evaluation platform
Promptfoo
Portkey
Humanloop
Ragas
RAG-specific evaluation framework
Sentry
DeepEval
Galileo AI
LLM output quality evaluation
LangWatch
Multi-turn agent simulation testing
PromptLayer
Confident AI
DeepEval open-source evaluation framework
Maxim AI
Distributed tracing for LLM and agent apps
Opik
Agenta
Lunary
Future AGI
Multimodal evaluation (text, image, audio, video)
Parea AI
Athina AI
Ashr
Multi-modal synthetic testing
Sentrial
Agent failure root cause analysis
Chamber
ML infrastructure automation
Moda
Hallucination detection
One platform for routing, observability, tracing, and evals across every LLM provider.