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Promptfoo vs Arize Phoenix: catalog facts
Promptfoo	Arize Phoenix
Freemium The open-source CLI is free; enterprise features are sold separately.	Freemium Phoenix is free to self-host; Arize AX is a separate managed paid platform.
Command line	Web, Self-hosted
Runs from the command line with a single npx command Compares prompts and models side by side	Tracing, evals, prompts and experiments in one tool Runs locally, in Docker or on Kubernetes
Red-teaming features are intended for authorized testing of your own applications Some reporting features belong to the paid enterprise edition	Source-available license rather than an OSI-approved one Some advanced features are in the separate paid Arize AX product
Downloadable app	Self-hosted, Hosted service
Open source	Closed source
License not stated	License: Elastic-2.0
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 26, 2026	Official website Full listing and sources Checked September 26, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.