Arize

Arize builds observability and evaluation tools that help AI engineers debug and improve agents, chatbots and other AI applications. Phoenix lets developers inspect model calls, retrieval and tool use, score outputs, refine prompts and compare application changes on shared datasets. It runs locally or can be self-hosted. Arize AX provides managed infrastructure, production observability and online evaluations, while its Alyx assistant helps teams run evaluations and investigate failures.

Arize was founded in 2020 by Jason Lopatecki, CEO, and Aparna Dhinakaran, CPO. Its team created OpenInference, conventions and instrumentation built around OpenTelemetry that capture model invocations alongside retrieval and external tool calls. Supported by both Phoenix and AX, OpenInference also works with other OpenTelemetry-compatible backends, allowing teams to use the instrumentation beyond Arize’s products.

Arize reported over 2 million monthly Phoenix downloads in 2025 and, as of August 2026, 1 billion evaluations per year. It raised a $70 million Series C in 2025. On August 13, 2026, Dynatrace announced a definitive acquisition agreement valuing the transaction at $915 million, subject to customary adjustments. Closing remained subject to regulatory review and customary conditions; both founders were to join Dynatrace at closing, with Lopatecki continuing to lead Arize.