Phoenix (Arize)
Observability & Evals · Free
Open-source AI observability and evaluation platform
At a glance
- Made by
- Arize AI
- Korean
- None (English and a few others only)
- Available on
- CLI
- Open source
- Open source (the license name is not listed on the page)
- GitHub
- 11,827 stars · NOASSERTION
What is Phoenix (Arize)?
Phoenix is an open-source AI observability and evaluation tool built by Arize that can run locally or be self-hosted in your own environment. It shows every step an agent goes through, including prompts, retrieval, tool calls, and outputs, as traces. You can create evaluations (evals) that score outputs, and build datasets from traces to run experiments. When self-hosted, traces stay within your own infrastructure.
- Tracing of every agent step
- Write evaluations (evals) that score outputs
- Human review and LLM-as-judge annotations
- Trace-based datasets and experiments
- Prompt IDE
- AI engineering agent that chats with your traces (PXI)
- Coding agent integration (npx skills add)
Who uses Phoenix (Arize) and for what
- Trace the causes of agent responses and debug them
- Verify changes against cost, latency, and performance criteria before deploying
- Observe while keeping sensitive data in your own infrastructure
Pricing
What you get for free — Yes (Phoenix open source, local or self-hosted / managed Arize AX Free: 25k spans/month, 1GB, 15-day retention)
| Plan | Price | Main limits |
|---|---|---|
| AX Free | $0/mo | 25k spans/month, 1GB, 15-day retention, unlimited users |
| AX Pro | $50/mo | 50k spans/month, 10GB, 30-day retention, unlimited users |
| AX Enterprise | Contact sales | Custom, SaaS or self-hosted |
Checked on the official pages on 2026-10-14. Prices and features can change, so check the official site again before paying. · Official pricing page
AI tools similar to Phoenix (Arize) (alternatives)
Phoenix (Arize) vs. alternatives at a glance
| AI | Pricing | Combos on the map | Connected tools | Free | Cheapest monthly | Korean |
|---|---|---|---|---|---|---|
| Phoenix (Arize) | Free | 0 | 5 | Yes | $50/mo | No |
| AgentOps | Free + paid | 0 | 5 | Yes | $40/mo | No |
| Helicone | Free | 0 | 5 | Yes | $79/mo | No |
| Langfuse | Free | 0 | 5 | Yes | $29/mo | No |
| Opik | Free | 0 | 5 | Yes | $19/mo | No |
5 of these 5 tools have a free plan. Cheapest paid plan: Opik ($19/mo).
Combo and connection counts are based on the relationships recorded on AI Galaxy Map (2026-10-26); they are not a quality ranking.
Phoenix (Arize) on AI Galaxy Map
- One of 27 AI tools in the Observability & Evals field.
- Connected to 5 other tools — #6 in its field.
Frequently asked questions
Can I use Phoenix (Arize) for free?
Yes (Phoenix open source, local or self-hosted / managed Arize AX Free: 25k spans/month, 1GB, 15-day retention). Prices can change, so check the official site before paying.
What AI can I use instead of Phoenix (Arize)?
Tools that do the same job, such as AgentOps, Helicone, Langfuse, Opik, are connected to it on the map.
Can I use Phoenix (Arize) in Korean?
None (English and a few others only)
Sources (official pages)
Checked on the official pages on 2026-10-14. Prices and features can change, so check the official site again before paying.