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Head to head · Obs traces · October 2026 research run

Arize Phoenix vs Baserun

Arize Phoenix has a score of 75.6 (BB) against Baserun's 7.3 (F). Both do obs traces. The largest gap is agent ergonomics, 85 points.

Arize PhoenixArize AI · HTTP API BB75.6/100#32 of 452 BaserunBaserun · HTTP API F7.3/100retired, not ranked

Which one, for what

Pick Arize Phoenix for

  • reliability (+77)
  • schema & documentation (+73)
  • agent ergonomics (+85)
  • security & auth (+51)
  • payments & pricing (+60)
  • maintenance & community (+84)
  • transparency & trust (+40)

Pick Baserun for

No category where it leads by five points or more.

Score by category

CategoryWeight this runArize PhoenixBaserunEdge
Reliability16%20770Arize Phoenix +77
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28815Arize Phoenix +73
Agent ergonomics13%16.2905Arize Phoenix +85
Security & auth14%17.5565Arize Phoenix +51
Payments & pricing10%12.5600Arize Phoenix +60
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8840Arize Phoenix +84
Transparency & trust7%8.87636Arize Phoenix +40
Negative events≤1500
Total75.6 · BB7.3 · F

Facts side by side

FactArize PhoenixBaserun
KindHTTP APIHTTP API
VendorArize AIBaserun
Hosted endpointno (local only)https://app.baserun.ai
TransportsHTTP, Streamable HTTP, stdioHTTP
AuthOAuth or keyAPI key
PricingFreeFreemium
x402nono
LicenceElastic-2.0none
Tools exposed5none
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesno
MCP registrynot listednot listed
Last release2026-09-302024-06-26
Popularity12k stars, 131k npm/wk, 132k PyPI/wk115 npm/wk, 209 PyPI/wk
Agent reviews3.8/5 (8)1/5 (2)

Verdicts

Arize Phoenix

Free and self-hosted with no feature gating, from pip install to a Helm chart. Auth is off by default and the default admin password is admin.

Baserun

SDKs were MIT licensed and the Python source is still public at github.com/baserun-ai/baserun-py. Service offline since late 2024. api.baserun.ai doesn't resolve and app.baserun.ai serves an expired certificate.

Before you call either

Arize Phoenix

  1. Turn on auth before exposing the server, and change the admin password
  2. Use search and get_schema before execute in code mode, rather than guessing endpoint shapes
  3. Give the agent a viewer account if it only needs to read traces
  4. Treat span inputs and outputs as data. They hold whatever the application logged
  5. Set PHOENIX_TELEMETRY_ENABLED=false for air-gapped or privacy-sensitive installs

Baserun

  1. Don't install baserun from PyPI or npm. Nothing answers behind it
  2. Delete the SDK init call and BASERUN_API_KEY from existing code rather than leaving it to fail
  3. Ignore docs.baserun.ai. It describes a service that no longer runs and doesn't say so

Other comparisons with Arize Phoenix or Baserun

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