Free
$0
- 1 GB data with no overage, $5 one-time Signals credit, 7-day retention, 1 project, 1 seat, community support
Laminar (lmnr) is an open-source observability platform for AI agents, licensed under Apache 2.0 and backed by Y Combinator. It captures LLM calls, tool calls, sub-agents, tokens, and cost from each agent run and shows them as a readable transcript, with browser session recording for browser agents.
Its main feature is Signals, which analyzes every agent run to surface failure modes you didn't define in advance and clusters similar failures into patterns. Signals run on flow-1, a model Laminar trained for trace analysis, and bill separately by the tokens used to analyze your traces. Error clusters can become eval datasets, and coding agents can query all trace data with SQL through Laminar's CLI and MCP server.
Compared with broader AI observability tools, Laminar focuses on debugging and evaluation, so prompt management and model routing aren't part of the product and prompt versions and gateway traffic stay in other tools. Self-hosting runs on Docker or Helm on AWS and GCP, and Enterprise adds on-premises deployment.
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Teams building long-running AI agents, including browser and coding agents, who need to debug agent runs at scale
Respan covers the tracing and evaluation work Laminar does, and adds prompt management and the AI router on the same platform. A failure found in a trace becomes a dataset, a fix gets tested against real data, and the new prompt version ships without a redeploy, all in one product.
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Respan turns a bad trace into a dataset, tests the fix against real data, and ships the new prompt version without a redeploy. Routing across 1,000+ models is built in, and you can start free.
Laminar vs LangSmith