Arize Phoenix vs Laminar
Both are observability & tracing tools. Here is how they actually differ on price, billing model and deployment.
Arize Phoenix
The default open-source choice for LLM tracing and eval - runs locally in under a minute, built on OpenTelemetry. The catch is the license - the server is Elastic License 2.0, source-available, not OSI open source.
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.
| Arize Phoenix | Laminar | |
|---|---|---|
| Category | Observability & Tracing | Observability & Tracing |
| Our rating | 4/5 | 4/5 |
| Starting price | $0 | $30/mo |
| Billing meter | No usage metering | span |
| Free plan | Yes | Yes |
| Free self-hosting | Yes, free | Yes, free |
| Best for | Teams that want fast, framework-agnostic OSS tracing and strong RAG eval, and who are not reselling Phoenix as a hosted service | 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 |
Our verdict on Arize Phoenix
The default open-source pick for good reasons - it starts in under a minute, the RAG eval is the best around, and it is built on OpenTelemetry so you are not locked to one framework. Just read the license before you build a business on it. The server is Elastic License 2.0, source-available rather than OSI open source, which only bites if you plan to offer Phoenix as a service - but it is not what "fully open source" implies.
Full Arize Phoenix review →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 →Frequently Asked Questions
What is the main difference between Arize Phoenix and Laminar?
Arize Phoenix: Teams that want fast, framework-agnostic OSS tracing and strong RAG eval, and who are not reselling Phoenix as a hosted service 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 Both sit in Observability & Tracing, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Arize Phoenix or Laminar?
It depends entirely on your workload shape, because they meter differently - Arize Phoenix bills on no usage metering and Laminar bills on span. Published starting prices are $0 and $30/mo 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 Arize Phoenix or Laminar?
Arize Phoenix: Yes, free. Laminar: Yes, free. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.