Langfuse vs W&B Weave
A side-by-side comparison of Langfuse and W&B Weave, two Observability tools, drawn from Ignaite's continuously-verified listings.
Compared from listings verified as of
Langfuse
ObservabilityOpen-source LLM observability. Self-hostable, OpenTelemetry-native.
View LangfuseAt a glance
| Attribute | Langfuse | W&B Weave |
|---|---|---|
| Category | Observability | Observability |
| Pricing | FREEMIUM | FREEMIUM |
| License | Open core | Open core |
| Deployment | Hybrid | Hybrid |
| Platforms | API, Web | API, Web |
| Model support (differs) | Model-agnostic | BYO key / model |
| Vendor (differs) | Langfuse | Weights & Biases |
The honest brief
Langfuse
The MIT-licensed, self-hostable answer to LangSmith — own your observability data, framework-agnostic.
- Own your observability data
- Framework-agnostic, OTel-native
- Tracing + evals + prompt mgmt
- Transparent unit-based pricing
- Self-host infra cost at scale
- Less deep LangChain integration
- Setup heavier than hosted-only
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