Overview

Rating

10.0 / 10

Rating

Best For

Teams building long-running AI agents, including browser and coding agents, who need to debug agent runs at scale

Best For

Engineering teams building agent and RAG systems who want OpenTelemetry-native observability with both self-hosted and managed options

Product Summary

Laminar is an open-source observability platform for AI agents, with agent tracing, automatic failure detection, evals, and full SQL access to trace data.

Product Summary

Phoenix is an open-source LLM observability and evaluation platform from Arize AI. It supports OpenTelemetry-based tracing across LLM and agent applications, with built-in evaluators, dataset management, and prompt playgrounds. Phoenix can be self-hosted with Docker or run via the Arize-hosted cloud version.

Starting Price

Open Source

Free Trial

Free Version

Yes

Free Version

Website

laminar.sh

Website

phoenix.arize.com

Key features

Core capabilities each platform advertises.

Laminar

Agent tracing with a readable transcript view
Signals for automatic failure detection and clustering
Evals and datasets built from production traces
Full SQL access through the editor, CLI, and MCP

Phoenix

OpenTelemetry-based LLM and agent tracing
Built-in evaluators for hallucination and relevance
Dataset and experiment management
Prompt playgrounds and versioning
Self-hosted Docker deployment or Arize cloud

Strengths and tradeoffs

What each tool does well, and the limitations to keep in mind.

Laminar

Pros

Apache 2.0 license with Docker and Helm self-hosting
Signals surface failure modes without predefined rules
Every plan includes evals, datasets, SQL access, and the agent debugger

Cons

No prompt management, so prompt versions live in a separate tool
No LLM gateway, so routing, failover, and spend limits need another product
Signals bill by usage on top of the plan, and the free tier gets only a one-time credit
Free tier is limited to 1 project, 1 seat, and 7-day retention

Phoenix

Pros

Open-source with active development by Arize
OpenTelemetry-native (no proprietary trace format lock-in)
Strong evaluator library out of the box
Both self-hosted and managed cloud options available
Upgrade path to full Arize enterprise platform

Cons

Laminar or Phoenix — which should you choose?

Choose Laminar if you wantChoose if you want

Debugging long-running browser and coding agents
Finding failure patterns across thousands of agent runs
Turning recurring failures into eval datasets

Choose Phoenix if you wantChoose if you want

OpenTelemetry-native LLM observability
Hallucination detection for RAG
Experiment tracking and golden-set evaluation
Prompt iteration and comparison
Self-hosted tracing for compliance-sensitive teams

Compare Laminar and Phoenix on your own traffic

10KFree traces/mo

1,000+Models

5 minSetup

Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.

Try Respan free

Laminar vs Phoenix (2026)

Overview

Key features

Strengths and tradeoffs

Laminar or Phoenix — which should you choose?

Compare Laminar and Phoenix on your own traffic

Other popular comparisons