PromptLayer
Prompt version control, A/B testing, and analytics platform
Verdict
Excellent for non-engineers to trigger prompt experiments. Prompt registry with versioning is clean. Pairs well with LangChain. Limited eval depth compared to Langfuse.
Other Observability & Evals
- LangfuseProduction
Open-source LLM engineering platform — traces, evals, prompts
- Phoenix (Arize)Stable
Open-source AI observability with embedding and RAG tracing
- Weave (W&B)Stable
Weights & Biases' LLM tracing and eval framework
- HeliconeStable
LLM gateway with logging, caching, and cost analytics
- OpenLLMetryEmerging
OpenTelemetry-based observability for LLMs
- BraintrustEmerging
End-to-end LLM evaluation and experimentation platform