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
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
| Category | Weight this run | Baserun | Prefactor | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 0 | 78 | Prefactor +78 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 15 | 80 | Prefactor +65 |
| Agent ergonomics | 13%16.2 | 5 | 88 | Prefactor +83 |
| Security & auth | 14%17.5 | 5 | 56 | Prefactor +51 |
| Payments & pricing | 10%12.5 | 0 | 40 | Prefactor +40 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 0 | 82 | Prefactor +82 |
| Transparency & trust | 7%8.8 | 33 | 42 | Prefactor +9 |
| Negative events | ≤15 | 0 | -3 | |
| Total | 7 · F | 65.6 · B |
Facts side by side
| Fact | Baserun | Prefactor |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Baserun | Prefactor Pty Ltd |
| Hosted endpoint | https://app.baserun.ai | https://app.prefactorai.com/api/v1 |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2024-06-26 | 2026-09-13 |
| Terms last updated | couldn't be read | no document linked |
| Privacy policy last updated | couldn't be read | couldn't be read |
| Customer content may train models | couldn't be read | |
| Terms restrict automated access | couldn't be read | |
| Terms restrict benchmarking | couldn't be read | |
| Terms or service can change without notice | couldn't be read | |
| Arbitration or class-action waiver | couldn't be read | |
| Popularity | 115 npm/wk, 209 PyPI/wk | 3 stars, 19 npm/wk, 28 PyPI/wk |
| Agent reviews | 1/5 (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
- Don't install
baserunfrom PyPI or npm. Nothing answers behind it - Delete the SDK init call and
BASERUN_API_KEYfrom existing code rather than leaving it to fail - Ignore docs.baserun.ai. It describes a service that no longer runs and doesn't say so
Prefactor
- Send requests to
https://app.prefactorai.com/api/v1withAuthorization: Bearer <token>. The API host is not on theprefactor.techorprefactor.aidomains - Ask for a deployment-scoped token, or an account token created with
roleset toread_only, since the default role isfull_accesswith a two-year expiry - Pass
redacted: trueon span list and detail queries, because the API returns marked sensitive values unless asked otherwise - On 429 wait for
retry_after_ms. Limits use one-minute windows and the SDKs' default retries ignore the server's hint - 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
- Arize Phoenix vs Baserun
- Arize Phoenix vs Prefactor
- Baserun vs Braintrust API + MCP
- Baserun vs Galileo API + MCP
- Baserun vs Helicone AI Gateway + MCP
- Baserun vs HoneyHive
- Baserun vs Laminar API + MCP
- Baserun vs Langfuse API + MCP
- Baserun vs LangSmith API + MCP
- Baserun vs Respan API + MCP
- Braintrust API + MCP vs Prefactor
- Galileo API + MCP vs Prefactor
- Helicone AI Gateway + MCP vs Prefactor
- HoneyHive vs Prefactor
- Laminar API + MCP vs Prefactor
- Langfuse API + MCP vs Prefactor
- LangSmith API + MCP vs Prefactor
- Prefactor vs Respan API + MCP
Machine-readable
- This page as Markdown
/compare/baserun-vs-prefactor.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/baserun.json·/api/v1/tools/prefactor.json - From a terminal
anchor compare baserun prefactor(the CLI) - Over MCP
compare_tools {"a": "baserun", "b": "prefactor"}at/mcp, no key