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Side-by-side features, use cases and pricing — because the right pick depends on your job and budget, not just the ranking.
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Openlayer
✓ verifiedFreemium
AI governance and observability platform with 100+ automated tests and real-time guardrails to evaluate and monitor ML/LLM systems.
24K visits/mo
✕
Arize AI
✓ verifiedFreemium
AI observability and evaluation platform to trace, evaluate and improve LLM agents in production, with an open-source Phoenix core.
248K visits/mo
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Helicone
✓ verifiedFreemium
LLM observability platform and AI gateway that lets teams route, log, debug and analyze their model requests.
100K visits/mo
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LangWatch
✓ verifiedFreemium
Platform to test, evaluate and observe LLM and voice AI agents, with prompt management and red-teaming for production.
23K visits/mo6.4K saves
Pricing
Basic: Free (20k inferences/mo, 1 member, 5 projects)
AX Free: $0/mo (25k spans/mo)
AX Pro: $50/mo (50k spans/mo)
Hobby: Free (10,000 requests/mo)
Pro: $79/mo (unlimited seats)
Team: $799/mo (SOC-2 & HIPAA)
Free trial available
Developer: €0 (50k events/mo)
Growth: €29/core-seat/mo (+ €5 per 100k events)
Core features
- ✦100+ automated AI tests
- ✦Offline evaluation and CI/CD for AI
- ✦Real-time observability and tracing
- ✦Guardrails against PII leaks, injection, hallucination
- ✦Data-quality and drift monitoring
- ✦Compliance/governance alignment
- ✦Git, SDK, CLI and REST API integration
- ✦Agent and LLM tracing
- ✦Large-scale evaluations
- ✦Open-source Phoenix observability
- ✦Alyx AI engineering agent
- ✦OpenTelemetry-based instrumentation
- ✦Experiments and prompt playgrounds
- ✦Request logging and LLM observability
- ✦AI gateway with routing and automatic fallbacks
- ✦Caching and rate limiting
- ✦Session, user and custom-property analytics
- ✦Prompts, playground and datasets for testing
- ✦Integrations with OpenAI, Anthropic, Azure and more
- ✦Scenario-based agent testing
- ✦LLM evaluation and quality scoring
- ✦Observability for cost and latency
- ✦Prompt management with GitHub sync
- ✦Voice AI simulation
- ✦LLM red-teaming and governance
Use cases
- →Evaluate models before production
- →Monitor live AI systems for issues
- →Prevent unsafe or non-compliant outputs
- →Catch data drift and quality problems
- →Debugging AI agents in production
- →Measuring LLM output quality
- →Catching regressions before deploy
- →Monitoring and debugging LLM apps
- →Analyzing model usage and cost
- →Caching responses to cut spend
- →Managing prompts and testing datasets
- →Catch agent issues before production
- →Evaluate and monitor LLM quality
- →Test voice AI agents at scale
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