Arize AI vs Braintrust (2026)
Overview
Arize AI provides an ML and LLM observability platform for monitoring model performance in production. For LLM applications, Arize offers trace visualization, prompt analysis, embedding drift detection, and retrieval evaluation. Their open-source Phoenix library provides local tracing and evaluation. Arize helps teams identify quality issues, debug failures, and continuously improve AI system performance.
Braintrust is an LLM evaluation and observability platform. Compare its evals, tracing, pricing, pros and cons, and alternatives.
Key features
Core capabilities each platform advertises.
- ML observability with LLM support
- Embedding drift detection
- Performance dashboards
- Automatic monitors and alerts
- Open-source Phoenix companion
- Experiments comparing prompts and models
- Code-based and LLM-as-judge scorers
- Datasets built from production traces
- Production logging and tracing
Strengths and tradeoffs
What each tool does well, and the limitations to keep in mind.
Pros
- Built on OpenTelemetry standards ensuring interoperability and avoiding vendor lock-in
- Impressive scale with 1 trillion spans processed and 5 million monthly OSS downloads
- Open-source Phoenix OSS option available for self-hosting
- Enterprise-proven with major clients like DoorDash, Instacart, Reddit, and Uber
- Comprehensive platform covering development, debugging, evaluation, and production monitoring
Cons
- Enterprise pricing starting at ~$1,000/month may be prohibitive for smaller teams
- Complexity of full feature set may require longer onboarding and learning curve
- Less transparent pricing compared to competitors with clear tier structures
Pros
- Unlimited users on every plan, including free
- Production traces, datasets, and experiments connect in one eval workflow
- Framework-agnostic SDKs across multiple languages
- Loop agent drafts scorers and datasets from your own data
Cons
- Processed data and scores bill separately, and both grow with eval volume
- 14-day retention on Starter and 30 days on Pro
- Gateway is in public preview with no SLA
- Self-hosting and custom data export are Enterprise only
Arize AI or Braintrust — which should you choose?
Choose Arize AI if you wantChoose if you want
- Production ML and LLM monitoring
- Embedding quality monitoring
- Model performance tracking
- Drift detection for AI systems
- Root cause analysis for AI failures
Choose Braintrust if you wantChoose if you want
- Iterating on prompts with production data
- Running evaluations across model versions
- Building golden datasets from production traffic
- Human review of LLM outputs
Compare Arize AI and Braintrust on your own traffic
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.
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