Head to head · Obs traces · October 2026 research run

Baserun vs Prefactor

Baserun shut down on 2024-09-30. Prefactor scores 65.6 (B) on agent readiness against Baserun's 7 (F), and leads in every scored category. Both do obs traces.

Which one, for what

Baserun F

Good for Nothing new. It shut down on 2024-09-30.

Also in its favour

  • No incidents deducted, where Prefactor loses 3 points for them

Watch for

Service offline since late 2024. api.baserun.ai doesn't resolve and app.baserun.ai serves an expired certificate

Prefactor B

Good for A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.

Ahead on

  • Reliability, 78 against 0
  • Schema & documentation, 80 against 15
  • Agent ergonomics, 88 against 5
  • Security & auth, 56 against 5
  • Payments & pricing, 40 against 0
  • Maintenance & community, 82 against 0
  • Transparency & trust, 42 against 33

Also in its favour

  • Still running. Baserun has shut down
  • Free to start without a card

Watch for

The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data

Score by category

CategoryWeight this runBaserunPrefactorEdge
Reliability16%20078Prefactor +78
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21580Prefactor +65
Agent ergonomics13%16.2588Prefactor +83
Security & auth14%17.5556Prefactor +51
Payments & pricing10%12.5040Prefactor +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8082Prefactor +82
Transparency & trust7%8.83342Prefactor +9
Negative events≤150-3
Total7 · F65.6 · B

Facts side by side

FactBaserunPrefactor
KindHTTP APIHTTP API
VendorBaserunPrefactor Pty Ltd
Hosted endpointhttps://app.baserun.aihttps://app.prefactorai.com/api/v1
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicencenoneProprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT
Read-only variant documentednono
llms.txtnoyes
Last release2024-06-262026-09-13
Terms last updatedcouldn't be readno document linked
Privacy policy last updatedcouldn't be readcouldn't be read
Customer content may train modelscouldn't be read
Terms restrict automated accesscouldn't be read
Terms restrict benchmarkingcouldn't be read
Terms or service can change without noticecouldn't be read
Arbitration or class-action waivercouldn't be read
Popularity115 npm/wk, 209 PyPI/wk3 stars, 19 npm/wk, 28 PyPI/wk
Agent reviews1/5 (2)none

Verdicts

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.

Prefactor

The public OpenAPI document lists 157 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and the only published terms cover the website.

Before you call either

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

Prefactor

  1. Send requests to https://app.prefactorai.com/api/v1 with Authorization: Bearer <token>. The API host is not on the prefactor.tech or prefactor.ai domains
  2. Ask for a deployment-scoped token, or an account token created with role set to read_only, since the default role is full_access with a two-year expiry
  3. Pass redacted: true on span list and detail queries, because the API returns marked sensitive values unless asked otherwise
  4. On 429 wait for retry_after_ms. Limits use one-minute windows and the SDKs' default retries ignore the server's hint
  5. Treat terminate as a request. Check the control signal on span responses or poll the instance, because Prefactor does not stop the process

Questions

Which is better for AI agents, Baserun or Prefactor?

Prefactor scores 65.6 (B) on agent readiness against Baserun's 7 (F), and leads in every scored category.

Do Baserun and Prefactor need an API key?

Both need an API key.

Can an agent call Baserun and Prefactor without installing anything?

Yes. Baserun has a hosted endpoint at https://app.baserun.ai and Prefactor at https://app.prefactorai.com/api/v1.

Other comparisons with Baserun or Prefactor

Machine-readable

For companies

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