Speed
Find the root cause, not just the error message
Most agent latency lives in tools and retrieval, not the model, so the answer usually isn’t where you’re looking.
Ship AI agents you can track, trace, and trust
Pydantic Logfire is the full-stack AI observability and evaluation platform for teams building to production.
- 10m spans free every month
- No credit card needed
- Install in 3LOC
From the team behind Pydantic Validation
- +60K GitHub stars
- 1BN+ monthly downloads
Trusted by every good Python developer, all FAANG companies and 20 of the 25 largest companies on NASDAQ.
The why
AI apps fail in ways your tools can’t see, so we put it all on one trace
Follow one request from the API call to the query underneath
Every step lands on one trace, in the order it happened, so you can follow a failure to the thing that caused it.
Your current tools only see half the story
One traces the AI. One watches the infrastructure. The failure usually happens somewhere between them.
Product
Logfire brings evidence to AI engineering
Full-stack observability, evaluation, and prompt control for AI apps. Every agent, every model, what it cost and how long it took, in a UI developers actually enjoy using.
Quality
Fix product issues before your customers find them
AI slop, hallucinations and silent regressions erode trust faster than any outage.
Cost
Know what’s worth keeping and cut what isn’t
Poor tooling doesn’t just slow you down, it burns budget with little to show for it.
What customers are saying
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“Logfire is the first observability product our team genuinely enjoys using.”
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“I've been using it from the early stages of implementation, appreciating the simple setup with just a few lines of code and clarity of the UI”
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“Everything in this product is easy to find, and you can extend it with your own tools if necessary, as it follows Python telemetry standards”
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“Clean interface, ease of use, killer features”
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“Logfire is extremely intuitive for agent builders and the SDK/MCP is built thoroughly for coding harnesses”
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“Logfire has been incredible for our platform; our development team couldn't be happier. We started with the basic observability and now have expanded to use the full AI tool set”
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“Super clean UI - Love that it's built on top of open telemetry - Really easy to setup and get logging w/ right away”
Source: Gartner Peer Insights
Much more than tracing
Evals, prompt rollouts, feature flags, the MCP server and the AI Gateway.
Customers
How teams are using Logfire
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Dosu cut agent debugging time 90% and saved $30k a year with Pydantic Logfire
“Being able to ask questions right within our coding agent and get cited metrics back has been invaluable. It's rare that I have to really dig into Logfire unless it's a really gnarly problem.”
Taylor Dolezal, Head of OSS
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Logfire and Pydantic Evals give Evergreen.ai end-to-end observability and continuous evaluation for financial-services AI agents.
“Having it built primarily off a first-class observability platform is the big thing that sold me as we're not running just LLM agents. We want to see observability on your API endpoints and all that other stuff too.”
Bryan Godwin
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AutonomyAI gives coding agents Logfire via MCP to check production after merge and file follow-ups.
“A cornerstone of how I am managing R&D is Pydantic Logfire and the feedback loop it enables for our agents.”
Tammuz Dubnov, co-founder and CTO
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Qualio uses Pydantic AI and Evals to turn plain-language quality criteria into auditable release gates.
“There's no point that has come where we'd say we're betting on the wrong horse. The decision a year ago was just the right one.”
Joshua Görner, Engineering Manager
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Pydantic AI grounds STCC's clinical RAG in triage decision trees; Logfire makes every answer reviewable.
“We approached this as a safety program first.”
Matthew Thompson, Product Manager, STCC
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Logfire gives GIC sub-second trace queries for live evaluation, deviation detection, and agent self-correction.
“We migrated from LangSmith to Logfire and the time it took to query our agent traces went down by 96.2%.”
Andrew Pignanelli, Founder and CEO
Security
Observability that passes review
SOC 2 Type 2, GDPR and HIPAA, with the audit report, pen test and DPA ready to send.
Blog
Latest articles
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You.com is now a Pydantic AI capability
You.com ships as two capabilities in Pydantic AI Harness. YouSearch gives an agent web search with excerpts and page reads, YouResearch gives it cited answers and multi-step research, and both hand your application structured citations it can render without parsing text.
Laís Carvalho
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The best Langfuse alternatives in 2026, honestly compared
A practical guide to Langfuse alternatives in 2026: what each one is licensed under, what its meter counts, who it suits, and when staying on Langfuse is the better call.
Bill Easton
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The 7 best LLM evaluation tools in 2026
A buyer's comparison of seven LLM evaluation tools: what each one meters, whether it scores curated datasets or live production traffic, what its license actually permits, and how much of your setup survives a switch.
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The best OpenTelemetry backends in 2026, honestly compared
A practical guide to OpenTelemetry backends in 2026: who each one is actually for, how each one meters usage, and what changes when your app includes LLMs.
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The best prompt management tools in 2026
An honest comparison of seven prompt management tools in 2026: who each one is for, how versioning, promotion, and rollout actually differ, and when prompts in your repository are still the right call.
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Your Pydantic AI agents just gained a voice
Realtime speech-to-speech support in Pydantic AI: the same agent, tools, and message history you already have, now over a live voice call. Provider-agnostic across OpenAI, Azure OpenAI, Gemini Live, and xAI, with browser WebRTC, server-side tools, gateway routing, and Logfire tracing.
Douwe Maan
Get started with Logfire for free
Sign up today and see your first trace in under 2 minutes
01 — Install
$ uv add logfire
Resolved 7 packages in 128ms
Installed 7 packages in 89ms
+ logfire02 — Instrument
import logfire
logfire.configure()
logfire.info('Hello {name}', name='world')Free up to 10m spans per month No credit card needed