Comparison

Arize Phoenix vs DeepEval (Confident AI)

A like-for-like, spec-level comparison. Both entries are verified against their docs and repo.

Arize Phoenix

Open-source LLM tracing and eval.

+ Open source with OTel foundations
+ Good LLM-as-a-judge evals built in
− Elastic license restricts some hosted offerings
− Enterprise features in the paid Arize cloud

DeepEval (Confident AI)

Open-source unit tests for LLMs.

+ Pytest-style DX, fits existing test suites
+ Open source metric library
− Confident AI cloud is proprietary
− Setup for custom metrics takes work

Spec	Arize Phoenix	DeepEval (Confident AI)
Category	eval-observability	eval-observability
License	Elastic-2.0	Apache-2.0
Open source	Yes	Yes
Self-hostable	Yes	Yes
MCP support	No	No
Pricing	free	free
Starting price	Self-host free	Self-host free
Models	multi	multi
Languages	python, typescript	python
GitHub stars	10.3k	16.5k
Last activity	2026-06-25	2026-06-25