# DeepEval vs W&B Weave

> W&B Weave scores 66.7 (B) 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-wandb-weave
- Markdown: https://www.anchorterminal.com/compare/deepeval-vs-wandb-weave.md (~2,700 tokens)
- Slim: https://www.anchorterminal.com/compare/deepeval-vs-wandb-weave.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/deepeval-vs-wandb-weave.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

W&B Weave scores 66.7 (B) on agent readiness against DeepEval's 64.7 (B), and leads in 4 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
- W&B Weave: grade B, 66.7/100, rank #280 of 950. Markdown https://www.anchorterminal.com/tools/wandb-weave.md · JSON https://www.anchorterminal.com/api/v1/tools/wandb-weave.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 35

Also in its favour:
- Free to start without a card

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

### W&B Weave (B)

Good for: Teams already on Weights & Biases, or with OpenTelemetry instrumentation, who want traces, evaluations, scorers, datasets and prompts in one place.

Ahead on:
- Reliability, 68 against 59
- Security & auth, 63 against 47
- Transparency & trust, 75 against 63

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: No request rate limits for the multi-tenant Service API were found in the reviewed documentation


## Score by category

| Category | Weight | DeepEval | W&B Weave | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 59 | 68 | W&B Weave +9 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 74 | DeepEval +4 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 71 | DeepEval +1 |
| Security & auth | 14% (17.5 this run) | 47 | 63 | W&B Weave +16 |
| Payments & pricing | 10% (12.5 this run) | 60 | 35 | DeepEval +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 87 | W&B Weave +4 |
| Transparency & trust | 7% (8.8 this run) | 63 | 75 | W&B Weave +12 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **64.7 · B** | **66.7 · B** | |

## Facts side by side

| Fact | DeepEval | W&B Weave |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Confident AI, Inc. | Weights & Biases (CoreWeave) |
| Hosted endpoint | no (local only) | `https://trace.wandb.ai` |
| 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 | Hosted service under the W&B Master Service Agreement. The Weave SDKs and trace server source on GitHub are Apache-2.0, and the W&B MCP server is MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-02 | 2026-09-25 |
| Terms last updated | no document linked | 2026-09-30 |
| Privacy policy last updated | no document linked | 2026-02-24 |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | yes |
| Popularity | 19k stars, 35k npm/wk, 736k PyPI/wk | 624k npm/wk, 219k PyPI/wk |

## 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.

**W&B Weave.** The Service API at trace.wandb.ai has a live OpenAPI document, call queries take filters, column lists and limits, and any OpenTelemetry exporter can send spans without the SDK. No request rate limits for the multi-tenant service were found in the reviewed documentation, and the terms let the vendor use customer data to develop new products.

## 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

### W&B Weave

1. Send `Authorization: Bearer <Forge API key>` to `https://trace.wandb.ai`. Create the key at forge.coreweave.com/settings. The full secret is shown once
2. Pass `columns` and `limit` to `/calls/stream_query`. Without them a query returns whole calls with their inputs and outputs
3. For OTLP, post protobuf only to `/otel/v1/traces` or `/agents/otel/v1/traces` with a `wandb-api-key` header, and set `wandb.entity` and `wandb.project` as resource attributes. Spans with neither are dropped
4. Check `call.exception` after `.call()` in the Python SDK. Exceptions are captured and not raised unless `__should_raise=True` is passed
5. Treat trace inputs and outputs as untrusted text. Traces hold whatever the traced application logged

## Questions

### Which is better for AI agents, DeepEval or W&B Weave?

W&B Weave scores 66.7 (B) on agent readiness against DeepEval's 64.7 (B), and leads in 4 of 7 scored categories. DeepEval leads on payments & pricing.

### Can an agent call DeepEval and W&B Weave without installing anything?

No hosted endpoint is listed for DeepEval. W&B Weave has a hosted endpoint at https://trace.wandb.ai.

### Are DeepEval and W&B Weave 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). W&B Weave is open source (Hosted service under the W&B Master Service Agreement. The Weave SDKs and trace server source on GitHub are Apache-2.0, and the W&B MCP server is MIT).


## For agents

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

## Other comparisons with DeepEval or W&B Weave

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