Laminar vs W&B Weave
Both are observability & tracing tools. Here is how they actually differ on price, billing model and deployment.
Laminar
An open-source, OpenTelemetry-native tracing and eval platform for AI agents, written in Rust. The only tool here you can self-host in full - but its billing unit, "Signals" measured in tokens spent reading traces, is genuinely hard to forecast.
W&B Weave
Weights & Biases' LLM tracing and evaluation product, now owned by CoreWeave after a reported $1.7B acquisition. Billed on GB of trace data ingested rather than spans or requests, which is a genuinely different cost model to everything else in the category.
| Laminar | W&B Weave | |
|---|---|---|
| Category | Observability & Tracing | Observability & Tracing |
| Our rating | 4/5 | 4/5 |
| Starting price | $30/mo | Per-seat plus usage |
| Billing meter | span | gb-ingested |
| Free plan | Yes | Yes |
| Free self-hosting | Yes, free | No or paid tier only |
| Best for | Teams building AI agents - especially browser agents - who want OpenTelemetry-native tracing they can self-host completely and don't mind an unusual billing model | Teams already running Weights & Biases for model training and experiment tracking, who want LLM traces and evals in the same platform as their fine-tuning runs and are comfortable with usage-based ingestion billing. |
Our verdict on Laminar
Laminar is the one platform here you can genuinely self-host end to end, and for a browser-agent or long-running-agent stack it's the most purpose-built option, with real credibility from OTel's co-creator as an angel and Browser Use documenting it as their integration. Two honest reservations. It's the youngest and smallest, and its billing - data GB plus Signals measured in tokens spent reading traces - is the hardest to forecast in the category. Self-host is the escape hatch from the billing puzzle, but the exact feature gap versus cloud isn't clearly documented, so verify it before you commit.
Full Laminar review →Our verdict on W&B Weave
W&B Weave is the strongest option in the category for one specific team - the one already on Weights & Biases. The lineage story is real and unmatched - a model fine-tuned in Sweeps and the eval run testing it appear in the same interface, which no AI-native competitor can offer because none of them do training. The instrumentation API is excellent, the custom scorers are plain Python, and the integration coverage is among the broadest available. Two things temper it. The billing metric is GB of trace data ingested, which is genuinely harder to forecast than per-span or per-seat pricing because it scales with prompt and context size, not just traffic. And CoreWeave now owns it following a reported $1.7B acquisition, which has come with interoperability pledges but leaves an open question about long-term direction. If you are not already a W&B customer, the bundled per-seat maths works against you and there are cheaper focused tools.
Full W&B Weave review →Frequently Asked Questions
What is the main difference between Laminar and W&B Weave?
Laminar: Teams building AI agents - especially browser agents - who want OpenTelemetry-native tracing they can self-host completely and don't mind an unusual billing model W&B Weave: Teams already running Weights & Biases for model training and experiment tracking, who want LLM traces and evals in the same platform as their fine-tuning runs and are comfortable with usage-based ingestion billing. Both sit in Observability & Tracing, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Laminar or W&B Weave?
It depends entirely on your workload shape, because they meter differently - Laminar bills on span and W&B Weave bills on gb-ingested. Published starting prices are $30/mo and Per-seat plus usage respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Laminar or W&B Weave?
Laminar: Yes, free. W&B Weave: No or paid tier only. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.