Our take
Pick Arize AX if agent / ML teams who will stay on AX Free at $0 (10 Signal issues, 25k spans, 1 GB, 15-day retention) while they open a first Signal list, then AX Pro at $50/month when they need 25 issues, 50k spans, or 30-day retention. Pick Langfuse if teams shipping LLM apps who need traces and a cost tile, not another chat UI. Skip Langfuse if people who only want a gateway (LiteLLM) or a framework (LangChain)
Best for
Arize AX An issue list you start at a public $
Langfuse Debug and cost-track generations
Free plan
Arize AX $0 · no card. 10 Signal issues / month. 25k trace spans / month. 1 GB ingestion. 15-day retention. SaaS. Unlimited users. Unlimited evals. 1 org / 1 space
Langfuse $0 · for the MIT core. ee/ is not the community license
Lowest paid
Arize AX AX Pro $50/mo
Langfuse Enterprise $2/mo
Next step up
Arize AX
Langfuse Core $29/mo
Coding agent
Arize AX Experiments
Langfuse
Runs where
Arize AX Local or hosted
Langfuse Local or hosted
Watch out
Arize AX Free Signal caps at 10 issues / month (account-wide, UTC)
Langfuse Hobby is two users and 30-day retention
Last checked
Arize AX 2026-10-23 · arize.com/pricing
Langfuse 2026-10-19 · langfuse.com/pricing
agent / ML teams who will stay on AX Free at $0 (10 Signal issues, 25k spans, 1 GB, 15-day retention) while they open a first Signal list, then AX Pro at $50/month when they need 25 issues, 50k spans, or 30-day retention.
Read the Arize AX pageteams shipping LLM apps who need traces and a cost tile, not another chat UI.
Read the Langfuse page
