Braintrust vs Phoenix

A side-by-side look at pricing, capabilities, pros, cons, and our editorial scores.

	Braintrust Evaluation	Phoenix Evaluation
Tagline	Eval, monitor, and improve AI products end-to-end.	Open-source LLM and agent observability platform with tracing, evals, and experimentation built on OpenTelemetry.
Category	Evaluation	Evaluation
Pricing	Freemium· Free up to 1k events/day; team from $249/mo	Freemium· Open source (ELv2) + free Phoenix Cloud; paid Arize AX for enterprise
Model	Platform (any LLM)	Multi-model
Editorial score	8.9 / 10	7.0 / 10
Use cases	evalsmonitoringprompt management	llm-tracingagent-debuggingllm-evaluationprompt-experimentsrag-observability
Pros	Full eval + observability in one tool Excellent UX Strong dataset/experiment tracking Closed loop dev → prod	Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell Native OpenTelemetry means no vendor lock-in for instrumentation Covers tracing, evals, annotation, and experiments in one tool Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work
Cons	Team pricing is steep Smaller than LangSmith ecosystem-wise	Self-hosting still requires you to manage storage, retention, and upgrades Eval UX is less polished than some managed competitors like LangSmith Free cloud tier is capped at two instances
Website	www.braintrust.dev	phoenix.arize.com

Pick Braintrust if

Pick Phoenix if

✅ Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell
✅ Native OpenTelemetry means no vendor lock-in for instrumentation
✅ Covers tracing, evals, annotation, and experiments in one tool
✅ Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work