# DeepEval vs Langfuse API + MCP

> Langfuse scores 72.7 (BB) to DeepEval's 64.7 (B) for evaluations. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/deepeval-vs-langfuse
- Markdown: https://www.anchorterminal.com/compare/deepeval-vs-langfuse.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/deepeval-vs-langfuse.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/deepeval-vs-langfuse.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

Langfuse API + MCP scores 72.7 (BB) on agent readiness against DeepEval's 64.7 (B), and leads in 6 of 7 scored categories. DeepEval leads on payments & pricing. Both do evaluations.

- DeepEval: grade B, 64.7/100, rank #343 of 950. Markdown https://www.anchorterminal.com/tools/deepeval.md · JSON https://www.anchorterminal.com/api/v1/tools/deepeval.json
- Langfuse API + MCP: grade BB, 72.7/100, rank #101 of 950. Markdown https://www.anchorterminal.com/tools/langfuse.md · JSON https://www.anchorterminal.com/api/v1/tools/langfuse.json
- Best agent tracing, monitoring and evaluation tools: https://www.anchorterminal.com/best/agent-observability/index.md
- All 120 evals comparisons: https://www.anchorterminal.com/compare/agent-observability/index.md

## Which one, for what

### DeepEval (B)

Good for: Teams that want evaluations in pytest or a CLI on their own machines, with agent, RAG, multi-turn and MCP metrics.

Ahead on:
- Payments & pricing, 60 against 40

Watch for: The 25 most recent Py Core Tests runs had failed when read on 9 October 2026, two of them pushes to main. Issue #3372 of 26 September reports the same

### Langfuse API + MCP (BB)

Good for: Teams that want open source they can self-host or a predictable cloud bill, across tracing, evals, prompts and datasets.

Ahead on:
- Reliability, 80 against 59
- Schema & documentation, 93 against 78
- Security & auth, 65 against 47
- Maintenance & community, 88 against 83
- Transparency & trust, 85 against 63

Also in its favour:
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install

Watch for: About 89 MCP tools load by default, writes included, with no server-side toolsets or read-only mode


## Score by category

| Category | Weight | DeepEval | Langfuse API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 59 | 80 | Langfuse API + MCP +21 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 93 | Langfuse API + MCP +15 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 74 | Langfuse API + MCP +2 |
| Security & auth | 14% (17.5 this run) | 47 | 65 | Langfuse API + MCP +18 |
| Payments & pricing | 10% (12.5 this run) | 60 | 40 | DeepEval +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 88 | Langfuse API + MCP +5 |
| Transparency & trust | 7% (8.8 this run) | 63 | 85 | Langfuse API + MCP +22 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **64.7 · B** | **72.7 · BB** | |

## Facts side by side

| Fact | DeepEval | Langfuse API + MCP |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Confident AI, Inc. | Langfuse (ClickHouse) |
| Hosted endpoint | no (local only) | `https://cloud.langfuse.com/api/public` |
| Transports |  | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache 2.0 for the Python and TypeScript packages and the agent skills. Confident AI, the hosted platform, is a proprietary service under its own terms | MIT (core), commercial licence for the ee directories |
| Tools exposed | none | 89 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-02 | 2026-10-01 |
| Terms last updated | no document linked | 2026-06-24 |
| Privacy policy last updated | no document linked | 2026-08-21 |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | not found in the text |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | not found in the text |
| Popularity | 19k stars, 35k npm/wk, 736k PyPI/wk | 35k stars, 3M npm/wk, 5.9M PyPI/wk |
| Agent reviews | none | 4/5 (2) |

## Verdicts

**DeepEval.** DeepEval runs evaluations and tracing locally under Apache 2.0 with no account, and writes each test run to JSON or SQLite. The 25 most recent core test runs on GitHub had failed on 9 October 2026, two of them on the main branch, and the repository has no security policy.

**Langfuse API + MCP.** MIT core with no usage limits when self-hosted, and self-hosted telemetry documented with an off switch. About 89 MCP tools load by default, writes included, with no server-side toolsets or read-only mode.

## Before you call either

### DeepEval

1. Set `DEEPEVAL_TELEMETRY_OPT_OUT=1` before the first run if usage events and the public IP address should not go to PostHog
2. Set a judge model key such as `OPENAI_API_KEY`, or use the non-LLM metrics. Most metrics call an LLM judge and bill the owner's provider account
3. Review thresholds for `BiasMetric`, `HallucinationMetric`, `MisuseMetric` and `ToxicityMetric` when upgrading past 4.2.0. Higher scores now mean better
4. Read results from `.deepeval/.latest_run_full.json` or a `results_folder`. `deepeval inspect` opens a terminal interface meant for a person
5. Pass an existing key with `deepeval login --api-key` in CI. Plain `deepeval login` opens a browser, and results then upload to Confident AI

### Langfuse API + MCP

1. Allowlist only the tools the agent needs. All 89 load by default and the write tools are among them
2. Ask `listObservations` for specific `fields`. Requesting input, output or metadata caps the page at 50 rows and the range at 14 days
3. Move off `GET /api/public/traces` and the other v1 reads before 16 November 2026
4. On 429, wait for `Retry-After`. MCP calls share the organisation's General API bucket
5. Pick the regional host (cloud, us.cloud, jp.cloud, hipaa.cloud) that matches the project's keys

## Questions

### Which is better for AI agents, DeepEval or Langfuse API + MCP?

Langfuse API + MCP scores 72.7 (BB) on agent readiness against DeepEval's 64.7 (B), and leads in 6 of 7 scored categories. DeepEval leads on payments & pricing.

### Can an agent call DeepEval and Langfuse API + MCP without installing anything?

No hosted endpoint is listed for DeepEval. Langfuse API + MCP has a hosted endpoint at https://cloud.langfuse.com/api/public.

### Are DeepEval and Langfuse API + MCP open source?

Yes. DeepEval is open source (Apache 2.0 for the Python and TypeScript packages and the agent skills. Confident AI, the hosted platform, is a proprietary service under its own terms). Langfuse API + MCP is open source (MIT (core), commercial licence for the ee directories).


## For agents

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

## Other comparisons with DeepEval or Langfuse API + MCP

- [Arize Phoenix vs DeepEval](https://www.anchorterminal.com/compare/arize-phoenix-vs-deepeval.md)
- [Arize Phoenix vs Langfuse API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-langfuse.md)
- [Baserun vs DeepEval](https://www.anchorterminal.com/compare/baserun-vs-deepeval.md)
- [Baserun vs Langfuse API + MCP](https://www.anchorterminal.com/compare/baserun-vs-langfuse.md)
- [Braintrust API + MCP vs DeepEval](https://www.anchorterminal.com/compare/braintrust-vs-deepeval.md)
- [Braintrust API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-langfuse.md)
- [Galileo API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langfuse.md)
- [Helicone AI Gateway + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/helicone-vs-langfuse.md)
- [HoneyHive vs Langfuse API + MCP](https://www.anchorterminal.com/compare/honeyhive-vs-langfuse.md)
- [Laminar API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/laminar-vs-langfuse.md)
- [Langfuse API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-langsmith.md)
- [Langfuse API + MCP vs LangWatch](https://www.anchorterminal.com/compare/langfuse-vs-langwatch.md)
- [Langfuse API + MCP vs MLflow Tracing](https://www.anchorterminal.com/compare/langfuse-vs-mlflow-tracing.md)
- [Langfuse API + MCP vs Prefactor](https://www.anchorterminal.com/compare/langfuse-vs-prefactor.md)
- [Langfuse API + MCP vs Pydantic Logfire](https://www.anchorterminal.com/compare/langfuse-vs-pydantic-logfire.md)
- [Langfuse API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/langfuse-vs-respan.md)
- [Langfuse API + MCP vs W&B Weave](https://www.anchorterminal.com/compare/langfuse-vs-wandb-weave.md)
- [DeepEval vs Galileo API + MCP](https://www.anchorterminal.com/compare/deepeval-vs-galileo.md)
- [DeepEval vs Helicone AI Gateway + MCP](https://www.anchorterminal.com/compare/deepeval-vs-helicone.md)
- [DeepEval vs HoneyHive](https://www.anchorterminal.com/compare/deepeval-vs-honeyhive.md)
- [DeepEval vs Laminar API + MCP](https://www.anchorterminal.com/compare/deepeval-vs-laminar.md)
- [DeepEval vs LangSmith API + MCP](https://www.anchorterminal.com/compare/deepeval-vs-langsmith.md)
- [DeepEval vs LangWatch](https://www.anchorterminal.com/compare/deepeval-vs-langwatch.md)
- [DeepEval vs MLflow Tracing](https://www.anchorterminal.com/compare/deepeval-vs-mlflow-tracing.md)
- [DeepEval vs Prefactor](https://www.anchorterminal.com/compare/deepeval-vs-prefactor.md)
- [DeepEval vs Pydantic Logfire](https://www.anchorterminal.com/compare/deepeval-vs-pydantic-logfire.md)
- [DeepEval vs Respan API + MCP](https://www.anchorterminal.com/compare/deepeval-vs-respan.md)
- [DeepEval vs W&B Weave](https://www.anchorterminal.com/compare/deepeval-vs-wandb-weave.md)