What is changing across AI Observability?
Teams pick Phoenix to self-host traces for free on OpenTelemetry, and the trouble they report starts at production volume. PagerDuty and Wayfair run Arize AX in production. Most teams that left Phoenix moved to Langfuse, and one dropped the tracer entirely.
Also covers Langfuse
For 200,000 traces a month and 10 users, GILD calculates US$1,340 on LangSmith Plus and US$199 to US$369 on Langfuse; Arize AX Pro came to US$1,610 at the US$0.0008 per-span overage Arize listed on Oct 25, 2026, a rate its pricing page no longer shows. Each tool meters a different unit, so price your own trace shape and retention before comparing plans.
Also covers LangSmith and Langfuse
