LangWatch
Open-source LLM observability and evaluation platform with OpenTelemetry-native tracing. Provides trace visualization, automated LLM-as-judge evaluations, dataset management, and prompt versioning. Self-hostable with a managed cloud option.
Langfuse
Open-source platform for tracing, evaluations, and prompt management. Self-hostable alternative to LangSmith with broad framework support. Acquired by ClickHouse in January 2026; OSS core continues with deeper ClickHouse-backed analytics.