Arize Phoenix vs Keywords AI / Respan

Detailed side-by-side comparison to help you choose the right tool

Arize Phoenix

🔴Developer

AI Observability

Arize Phoenix is an open-source AI observability and evaluation platform for tracing, testing, and improving LLM applications and agents.

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Starting Price

Free

🔴Developer

AI observability

LLM monitoring and gateway platform for AI applications

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Starting Price

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Feature	Arize Phoenix	Keywords AI / Respan
Category	AI Observability	AI observability
Pricing Plans	4 listed plans	3 listed plans
Starting Price	Free	$0
Key Features	• LLM Tracing & Observability • Evaluation Framework • Experiment Management	• End-to-end agent tracing with prompt, tool call and response context • Evaluation workflows with human review, code checks and LLM judges • Gateway, observability, evaluations and prompt optimization features

✓Open-source Phoenix can run locally or on controlled infrastructure without a software license fee.
✓OpenTelemetry tracing reduces instrumentation lock-in.
✓Datasets, experiments, evaluations, and Prompt IDE connect evidence to changes.
✓AX Free and Pro include unlimited users and evaluations at published prices.

✗Self-hosting shifts upgrades, storage, access control, backups, and availability to the user's team.
✗Agent runs can generate many spans, consuming 25,000 or 50,000 allowances quickly.
✗Managed retention of 15 or 30 days may be short for audits or long incident cycles.
✗Fetched pages did not explicitly document native MCP support.

✓Free Pro tier includes full platform access, 100k logs, 1k scores, 5 datasets, 2 evaluators and 5 prompts
✓Team tier adds unlimited datasets, evaluators and prompts plus private Slack and SOC 2 report
✓Good provider coverage: OpenAI, Anthropic, OpenRouter, Groq, Fireworks, Together AI, Perplexity, Azure OpenAI and Bedrock
✓Security signals include ISO 27001, SOC 2 and HIPAA references on the fetched page

✗Branding appears as Respan on fetched pages, so teams should verify the current product/legal name
✗Additional logs are listed at $8 per 100k logs, which can matter for high-volume apps
✗Enterprise items such as HIPAA BAA, custom SLAs and dedicated support require sales

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