LangSmith vs W&B Weave
A side-by-side comparison of LangSmith and W&B Weave, two Observability tools, drawn from Ignaite's continuously-verified listings.
Compared from listings verified as of
At a glance
| Attribute | LangSmith | W&B Weave |
|---|---|---|
| Category | Observability | Observability |
| Pricing | FREEMIUM | FREEMIUM |
| License (differs) | Proprietary | Open core |
| Deployment (differs) | Cloud | Hybrid |
| Platforms | API, Web | API, Web |
| Model support (differs) | Model-agnostic | BYO key / model |
| Vendor (differs) | LangChain | Weights & Biases |
The honest brief
LangSmith
Deepest native LangChain/LangGraph tracing — but cloud-only, where Langfuse lets you self-host the same.
- Native LangChain/LangGraph tracing
- Works standalone via SDKs
- Datasets + eval orchestration
- Prompt playground built in
- Closed source, cloud-only
- Self-host is Enterprise-only
- Best value inside LangChain stack
W&B Weave
One @weave.op decorator handles both tracing and evaluation, tied into the mature W&B experiment-tracking platform.
- Single decorator traces every call
- Tracing + evaluation in one SDK
- LLM-as-judge and custom scorers
- Apache-2.0 SDK
- Ties into W&B experiment tracking
- Traces land in W&B hosted platform
- Best value if already on W&B
- Free only for solo use