# 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. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/baserun-vs-langwatch
- Markdown: https://www.anchorterminal.com/compare/baserun-vs-langwatch.md (~2,300 tokens)
- Slim: https://www.anchorterminal.com/compare/baserun-vs-langwatch.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/baserun-vs-langwatch.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

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.

- Baserun: grade F, 7/100, rank retired, not ranked. Markdown https://www.anchorterminal.com/tools/baserun.md · JSON https://www.anchorterminal.com/api/v1/tools/baserun.json
- LangWatch: grade B, 65.5/100, rank #291 of 842. Markdown https://www.anchorterminal.com/tools/langwatch.md · JSON https://www.anchorterminal.com/api/v1/tools/langwatch.json

## Which one, for what

### Baserun (F)

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

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

| Category | Weight | Baserun | LangWatch | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 0 | 53 | LangWatch +53 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 15 | 87 | LangWatch +72 |
| Agent ergonomics | 13% (16.2 this run) | 5 | 67 | LangWatch +62 |
| Security & auth | 14% (17.5 this run) | 5 | 71 | LangWatch +66 |
| Payments & pricing | 10% (12.5 this run) | 0 | 40 | LangWatch +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 0 | 90 | LangWatch +90 |
| Transparency & trust | 7% (8.8 this run) | 33 | 75 | LangWatch +42 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **7 · F** | **65.5 · B** | |

## Facts side by side

| Fact | Baserun | LangWatch |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Baserun | Reasoning Engine B.V. (LangWatch) |
| Hosted endpoint | `https://app.baserun.ai` | `https://app.langwatch.ai` |
| Transports | HTTP | HTTP, Streamable HTTP, SSE (legacy), stdio |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |
| Tools exposed | none | 101 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2024-06-26 | 2026-10-02 |
| Terms last updated | couldn't be read | 2026-09-22 |
| Privacy policy last updated | couldn't be read | 2026-09-29 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | yes |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | yes |
| Arbitration or class-action waiver | couldn't be read | not found in the text |
| Popularity | 115 npm/wk, 209 PyPI/wk | 4.9k stars, 50k npm/wk, 87k 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.

**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).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/baserun-vs-langwatch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/baserun-vs-langwatch.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "baserun", "b": "langwatch"}`. From a terminal: `anchor compare baserun langwatch`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/baserun.json and https://www.anchorterminal.com/api/v1/tools/langwatch.json

## Other comparisons with Baserun or LangWatch

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