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Head to head · Obs traces · October 2026 research run

Baserun vs LangWatch

Baserun shut down on 2024-09-30. LangWatch scores 65.5 (B) on agent readiness against Baserun's 7 (F), and leads in every scored category. Both do obs traces.

BaserunBaserun · HTTP API F7/100retired, not ranked LangWatchReasoning Engine B.V. (LangWatch) · HTTP API B65.5/100#291 of 841

Which one, for what

Baserun F

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

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

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

LangWatch B

Good for Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.

Ahead on

  • Reliability, 53 against 0
  • Schema & documentation, 87 against 15
  • Agent ergonomics, 67 against 5
  • Security & auth, 71 against 5
  • Payments & pricing, 40 against 0
  • Maintenance & community, 90 against 0
  • Transparency & trust, 75 against 33

Also in its favour

  • Still running. Baserun has shut down
  • Runs on your own machine
  • Free to start without a card
  • Open source

Watch for

The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no readOnlyHint or destructiveHint annotations in the source

Score by category

CategoryWeight this runBaserunLangWatchEdge
Reliability16%20053LangWatch +53
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21587LangWatch +72
Agent ergonomics13%16.2567LangWatch +62
Security & auth14%17.5571LangWatch +66
Payments & pricing10%12.5040LangWatch +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8090LangWatch +90
Transparency & trust7%8.83375LangWatch +42
Negative events≤150-2
Total7 · F65.5 · B

Facts side by side

FactBaserunLangWatch
KindHTTP APIHTTP API
VendorBaserunReasoning Engine B.V. (LangWatch)
Hosted endpointhttps://app.baserun.aihttps://app.langwatch.ai
TransportsHTTPHTTP, Streamable HTTP, SSE (legacy), stdio
AuthAPI keyOAuth or key
PricingFreemiumFreemium
x402nono
LicencenoneApache 2.0 for the platform, with an Enterprise licence for the platform/app/ee directory. The SDKs and the MCP server are MIT
Tools exposednone101
Read-only variant documentednono
llms.txtnoyes
Last release2024-06-262026-10-02
Terms last updatedcouldn't be read2026-09-22
Privacy policy last updatedcouldn't be read2026-09-29
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readyes
Terms restrict benchmarkingcouldn't be readnot found in the text
Terms or service can change without noticecouldn't be readyes
Arbitration or class-action waivercouldn't be readnot found in the text
Popularity115 npm/wk, 209 PyPI/wk4.9k stars, 50k npm/wk, 87k 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.

LangWatch

API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation.

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

LangWatch

  1. Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do
  2. Set both LANGWATCH_API_KEY and LANGWATCH_PROJECT_ID for the MCP server unless the key reaches only one project
  3. Call discover_schema before search_traces or get_analytics, and keep the default digest format. json returns the full raw trace
  4. Allowlist MCP tools in the client. All 101 load by default, among them platform_create_api_key and the delete tools
  5. Follow next_cursor until it is null on list endpoints. A full page does not mean more rows exist

Questions

Which is better for AI agents, Baserun or LangWatch?

LangWatch scores 65.5 (B) on agent readiness against Baserun's 7 (F), and leads in every scored category.

Do Baserun and LangWatch need an API key?

Baserun needs an API key. LangWatch takes an API key or an OAuth sign-in.

Can an agent call Baserun and LangWatch without installing anything?

Yes. Baserun has a hosted endpoint at https://app.baserun.ai and LangWatch at https://app.langwatch.ai.

Are Baserun and LangWatch open source?

No open-source release is listed for Baserun. LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).

Other comparisons with Baserun or LangWatch

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