Arize AI

About Arize AI

Financials

Dated, source-cited figures. Estimates are marked.

Products by Arize AI

All products by Arize AI reviewed by our AI panel of experts.

Arize PhoenixLLM Platforms

Open-source observability for LLM and AI applications

From $50/mo8.1/10

How Our Review Panel Scores Arize AI

Six independent reviewer personalities assessed Arize AI's product on their own terms. They landed within 0.4 points of each other, an unusually strong consensus.

Averaged across 1 reviewed product in our catalog. Scores are out of 10.

Competitive Landscape

Who Arize AI competes with, and how they differ.

Langfuse8.0/10

Open-source LLM observability and tracing platform (33K+ GitHub stars) that competes most directly with Arize Phoenix at the open-source layer; Langfuse joined the ClickHouse open-source analytics group in January 2026, giving it a data-infrastructure parent rather than Arize's independent path.

1 product reviewed on TopReviewed

LangSmith (LangChain)8.1/10

LLM tracing and evaluation tooling built and distributed as part of the LangChain framework, so adoption tracks LangChain's own developer base rather than being framework-agnostic like Arize's platform.

2 products reviewed on TopReviewed

Galileo AI7.7/10

Enterprise AI evaluation and observability platform (founded 2021) focused on agent reliability and production guardrails, competing with Arize AX for enterprise LLM/agent monitoring contracts.

1 product reviewed on TopReviewed

Helicone7.9/10

Open-source LLM gateway and observability tool centered on cost, latency, and usage monitoring via a proxy layer — a lighter-weight, ops-focused alternative to Arize's broader evaluation and drift-detection platform.

1 product reviewed on TopReviewed

Weights & Biases8.0/10

Originated as an ML experiment-tracking platform and later extended into LLM tracing/evaluation via its Weave product, overlapping with Arize on LLM observability; W&B was acquired by CoreWeave for $1.7B in March 2025, making it part of an AI-infrastructure cloud provider rather than an independent observability vendor like Arize.

1 product reviewed on TopReviewed

Company Timeline

Key milestones in Arize AI's history, with sources.

1. Aug 13, 2025Milestone

   AFWERX Direct-to-Phase-II SBIR contract selected

   The U.S. Air Force's AFWERX program selected Arize AI for a Direct-to-Phase-II Small Business Innovation Research contract (~$1.2M/year, 12-month period of performance) to adapt its AI engineering tools for the Department of the Air Force's NIPRGPT/GCP environment.

   prnewswire.com
2. Feb 20, 2025Funding

   Series C — $70M led by Adams Street Partners

   Arize AI raised a $70M Series C led by Adams Street Partners, with participation from M12 (Microsoft's venture fund), Sinewave Ventures, OMERS Ventures, and strategic backers Datadog and PagerDuty, to expand its AI observability and LLM evaluation platform.

   prnewswire.com
3. Nov 19, 2024Partnership

   Collaboration with Microsoft on enterprise generative AI deployment

   Arize AI announced a collaboration with Microsoft aimed at enabling more effective enterprise deployment of generative AI systems.

   prnewswire.com
4. Jul 11, 2024Partnership

   Joint platform with LlamaIndex for evaluating LLM applications

   Arize AI and LlamaIndex rolled out a joint platform to evaluate LLM applications, combining Arize's evaluation tooling with LlamaIndex's data framework for LLM apps.

   prnewswire.com
5. Apr 26, 2023Launch

   Arize Phoenix — first open-source LLM evaluation library

   Arize AI debuted Phoenix, described as the first open-source library purpose-built for evaluating large language models (e.g. GPT-4), including anomaly detection over LLM embeddings, drift surfacing, and cluster export for troubleshooting.

   prnewswire.com
6. Sep 8, 2022Funding

   Series B — $38M led by TCV

   Arize AI raised a $38M Series B led by TCV, with participation from Battery Ventures, Foundation Capital, and Swift Ventures, to scale its machine learning observability platform.

   prnewswire.com
7. Sep 28, 2021Funding

   Series A — $19M led by Battery Ventures

   Arize AI raised a $19M Series A led by Battery Ventures, with participation from Foundation Capital, Trinity Ventures, The House Fund, and Swift Ventures, for its ML observability platform.

   prnewswire.com
8. 2020Founded

   Arize AI founded in Berkeley, California

   Arize AI was founded by CEO Jason Lopatecki and CPO Aparna Dhinakaran to provide observability, evaluation, and guardrails for AI/ML systems in production.

   techcrunch.com