Arize AI
Also known as: Arize AX, Phoenix
AI observability and evaluation platform that traces, evaluates, and monitors LLM applications and agents, with an open source core in Phoenix.
Arize AI is an observability, evaluation and improvement platform for AI agents, sold in two forms on the same open standards. Phoenix is the open-source project, run locally, in containers or in the customer's cloud, with tracing, evaluation, datasets, experiments, a playground, prompt management, a built-in assistant, a CLI and a remote MCP server. Arize AX is the managed platform, backed by the adb datastore, which syncs trace data to BigQuery, Databricks or Snowflake.
AX traces agents on OpenTelemetry and OpenInference, the semantic conventions Arize maintains, with path and graph views of each trajectory, cost and latency, sessions, dashboards and monitors. It runs online evals on production traces and offline evals on datasets, including trace, session and agent-as-a-judge evals, human annotation and labeling queues, and Prompt Learning optimization. Two built-in agents work on the customer's agents: Alyx, an AI engineering agent that runs evals and debugs issues, and Signal, which surfaces failure patterns from production telemetry, traces root causes and proposes review-ready fixes.
Arize states SOC 2 Type II, ISO 27001, PCI DSS, HIPAA and GDPR certification, offers US, EU or CA data regions, and adds self-hosted deployment, Enterprise SSO and audit logs on Enterprise. AX Free and Phoenix are free, AX Pro is $50 a month, and AX Enterprise is custom. Arize reports a trillion spans processed and a billion evaluations a year.
Vendor details
Canonical URL
https://arize.com
Category
Agent infrastructure
Subcategory
Observability and evaluation
Funding status
Founded January 2020 by Jason Lopatecki (CEO) and Aparna Dhinakaran (Chief Product Officer) in Berkeley, California. Has raised about $131M across rounds through Series C, and acquired Velvet in 2025. Remains independent.
Company status
independent
Use cases & customers
Primary use cases
Target customers
Deployment options
Integrations
OpenTelemetry and OpenInference native instrumentation with framework integrations for OpenAI, Anthropic, LangChain, LangGraph, CrewAI, and LlamaIndex. Python and JavaScript SDKs, trace export to backends like Jaeger, Prometheus, and Grafana, adb Data Fabric sync to BigQuery, Databricks, and Snowflake, and a CLI usable from Cursor and Claude Code.
In practice
Your agent works in demos but fails unpredictably in production. You instrument it with Arize, trace every prompt, tool call, and route, and find the exact step where it breaks.
You want to know whether a prompt change actually improved quality, not just feels better. You run LLM as a judge evaluations on curated datasets and on live traffic, and compare results before shipping.
You run both classic ML models and LLM agents and are tired of two monitoring stacks. Arize watches drift and performance on the models and traces and evaluates the agents in one place.
Sources & related URLs
Related / legacy domains
Agentic Index coverage score
9.0 / 14 capabilities · 64%
| Integrations & Tool Calling | Partial |
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More than 40 integrations with models, frameworks and AI tools instrument the customer's application to send traces into Arize, code evaluators run in E2B, Daytona, Vercel or Modal sandboxes, and Data Fabric syncs trace data to warehouses. These move telemetry in and data out. No connectors that let an agent take authenticated actions in outside systems are documented. SourceArize, arize.com homepage and pricing and the Phoenix README on github.com/Arize-airead 2026-09-21 |
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| Workflow Orchestration | Not documented |
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Agents that Arize observes, evaluates and improves run elsewhere, and no workflows that sequence, branch or retry an agent's steps, or mix deterministic nodes with agent steps, are documented. SourceArize, arize.com pricing and homepageread 2026-09-21 |
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| Knowledge Grounding & RAG | Not documented |
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RAG pipelines built elsewhere are traced and evaluated in Arize, but no retrieval structure over the customer's own documents that grounds an agent's answers is documented. SourceArize, arize.com homepage and pricingread 2026-09-21 |
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| Human Oversight & Guardrails | Partial |
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Signal generates review-ready fixes for a person to review rather than applying them, so changes Arize's agents propose pass through human review. No approval step, escalation rule or pause before an agent acts at run time is documented, nor are autonomy modes that treat low risk and high risk actions differently. SourceArize, arize.com homepage and pricingread 2026-09-21 |
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| Security, Identity & Governance | Full |
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Arize states it is certified to SOC 2 Type II, ISO 27001, PCI DSS, HIPAA and GDPR, with a Trust Center, and its plans document organization- and space-level RBAC, service accounts, Enterprise SSO and audit logs. SourceArize, arize.com homepage and pricingread 2026-09-21 |
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| Observability & Auditability | Full |
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Agents are traced in Arize AX on OpenTelemetry with path and graph visualizations of each agent trajectory, token, latency and cost tracking, session and multi-modal tracing, custom dashboards, metrics, monitors and views on traces, audit logs on Enterprise, retention by plan (15 days Free, 30 days Pro, custom Enterprise), and Data Fabric sync of trace data to BigQuery, Databricks or Snowflake. SourceArize, arize.com pricing and homepageread 2026-09-21 |
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| Memory & State Persistence | Not documented |
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For tracing and evaluation, Arize stores agent trajectories and sessions, and no session, conversation or long-term memory that an agent reads back as context is documented. SourceArize, arize.com homepage and pricingread 2026-09-21 |
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| Deployment & Data Residency | Full |
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Every Arize AX plan chooses a US, EU or CA data region, Enterprise adds self-hosted deployments, and open-source Phoenix runs locally, in containers with Docker and Helm, or in the customer's cloud. SourceArize, arize.com pricing and the Phoenix README on github.com/Arize-airead 2026-09-21 |
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| Prebuilt Agents, Templates & Packs | Full |
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Ready-made agents a buyer switches on include Alyx, an AI engineering agent that runs evals, debugs issues and improves the customer's agents, and Signal, whose agents find production issues and propose fixes, each working without the other, alongside managed agents on Enterprise and packaged skills that teach coding agents to trace, evaluate and debug with Phoenix. Those are role-specific agents and ready-made workflows. SourceArize, arize.com homepage and pricing and the Phoenix README on github.com/Arize-airead 2026-09-21 |
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| Triggers & Channel Coverage | Full |
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Online evals run on traces and spans as they arrive, custom monitors fire on production conditions, and Signal's agents surface failure patterns from production telemetry, trace root causes and generate proposed fixes, so Arize's work starts from incoming telemetry with no person initiating each run. SourceArize, arize.com homepage and pricingread 2026-09-21 |
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| Model Flexibility & Routing | Full |
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The AI provider behind Arize's own agents and evaluators can be customized, with the customer's own key alongside Arize-managed models on Enterprise, and the Phoenix playground compares models and replays traced LLM calls against them. Customers control the models Arize's own AI features run on, though bringing their own key requires the Enterprise tier. SourceArize, arize.com pricing and the Phoenix README on github.com/Arize-airead 2026-09-21 |
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| APIs, SDKs & MCP Extensibility | Full |
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Arize publishes Python and TypeScript client, OpenTelemetry and evals packages, a GraphQL API, a CLI that fetches traces, datasets and experiments, and a remote MCP server at each Phoenix instance's /mcp endpoint that MCP clients use to query traces, datasets and experiments, all on the OpenInference and OpenTelemetry standards it maintains. That is a stable API and SDK for Arize's own platform, with MCP served. SourceArize, the Phoenix README on github.com/Arize-ai and arize.com homepageread 2026-09-21 |
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| Testing, Debugging & Optimization | Full |
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Testing covers online evals on traces and spans and offline evals on datasets and experiments, with trace evals of agent trajectories, session evals of multi-turn conversations, agent-as-a-judge and custom code evaluators, evaluator alignment, human annotations and labeling queues, agent experimentation in the playground, and Prompt Learning optimization; Phoenix adds open-source evals, datasets and experiments. That tests the customer's agent against datasets before production and scores quality over time. SourceArize, arize.com pricing and the Phoenix README on github.com/Arize-airead 2026-09-21 |
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| Browser & Computer Use | Not documented |
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Arize observes, evaluates and improves agents, and no browser, desktop or computer control by an agent is documented. SourceArize, arize.com homepageread 2026-09-21 |
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The Agentic Index coverage score grades every vendor Full, Partial or Not documented against the same 14 buyer facing capabilities, from public evidence only. Each capability links to how all vendors in the index score on it. How this evidence is graded
Recent platform changes
Phoenix v20.18.0 shows evaluation results directly in the trace tree, so eval scores and labels sit beside each step of an agent or LLM run.
Bears on: Observability / auditability
View sourceArize AI entered into a definitive agreement to be acquired by observability vendor Dynatrace in a cash and stock transaction valued at $915 million. The acquisition will combine Arize's AI agent evaluation and experimentation software with Dynatrace's production monitoring capabilities.
Bears on: Observability / auditability
View sourceArize announced Signal, a capability within Arize AX that utilizes autonomous agents to investigate and resolve software issues automatically. Signal surfaces failure patterns from production telemetry, uncovers root causes, and generates review-ready fixes as part of a self-improving feedback loop.
Bears on: Agent capability
View sourcePricing
From $50/mo · free tier + open source
Flat monthly plan with usage overage on trace spans and ingestion (GB)
Included quota
AX Free includes 25,000 trace spans and 1 GB ingestion per month with 15 day retention. AX Pro includes 50,000 spans and 10 GB per month with 30 day retention. Enterprise allowances are custom.
What is public
Arize publishes full self serve pricing: AX Free and Phoenix open source are free, AX Pro is $50 per month, and AX Enterprise is custom. Span and ingestion allowances and overage rates are listed per tier.
Billing mechanics
Tiers meter trace spans and data ingestion per month with fixed retention windows. AX Pro is a flat $50 monthly fee that includes 50,000 spans and 10 GB; beyond that, spans bill at $0.0008 each and ingestion at $3 per GB. Enterprise replaces fixed limits with negotiated allowances.
Cost watchouts
Span and ingestion overage on AX Pro can grow with high volume agents. The gap between $50 Pro and custom Enterprise is large with no middle tier.
Variable cost rationale
The $50 Pro plan includes generous span and ingestion allowances, but high traffic agents that exceed 50k spans or 10 GB a month accrue per span and per GB overage, and serious scale pushes teams to a custom Enterprise contract.
Additional watchouts
Offline evaluation on data older than the tier retention window (15 or 30 days) is not available until Enterprise. Compliance certifications and enterprise SSO are Enterprise only.
Overage / add-ons
On AX Pro, additional trace spans are $0.0008 each and additional ingestion is $3 per GB. Enterprise overage is negotiated.
Sales call required
Mixed (some tiers require a call)
Free / trial
AX Free (25k spans/mo, 1 GB, 15 day retention, 10 Signal issues/mo) and Phoenix open source, both free
Lowest paid plan
AX Pro: $50/mo
Commercial notes
Phoenix open source is a genuine free path with no feature gates for teams that self host. The paid path runs from $50 Pro to a custom Enterprise contract, with compliance (SOC2 Type II, HIPAA), audit logs, enterprise SSO, dedicated support, and adb Data Fabric reserved for Enterprise.
Key ambiguities
Total cost at scale depends on monthly span volume and ingestion, and on whether compliance needs force a move to the custom Enterprise tier.
Cancellation / refund
AX Free and AX Pro are self serve and month to month. Enterprise terms are contractual. Public cancellation and refund details are limited.
Support SLA / resale
Community support on Free, email support on Pro, dedicated support with a contractual uptime SLA on Enterprise.
Missing data
Enterprise pricing is custom and not listed; third party reports put it in the tens of thousands of dollars per year. Startup pricing is available by application.
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Alternatives to Arize AI
The closest documented capability profiles to Arize AI among agent infrastructure platforms tracked by Agentic Index, ordered by similarity on the same 14 point evidence the rankings use. No vendor pays for placement.
- Confident AI8.5 / 14A lighter documented profile than Arize AI
- HoneyHive8.5 / 14A lighter documented profile than Arize AI
- Langfuse8.5 / 14A lighter documented profile than Arize AIArize AI vs Langfuse →
- F5 AI Guardrails9.0 / 14Fuller documented coverage on Human Oversight & Guardrails
- Freeplay8.0 / 14A lighter documented profile than Arize AI
- Galileo9.0 / 14Fuller documented coverage on Human Oversight & GuardrailsArize AI vs Galileo →
Similarity is computed from each vendor's Agentic Index coverage score evidence, axis by axis, not from the totals. How this evidence is graded