Logfire review

Q: How do I install Logfire?

Run pip install logfire. The install section above has the other options from the project's README.

Logfire is an observability platform from the Pydantic team for LLM apps, agents, and Python services, built on OpenTelemetry.

Updated Nov 1, 2026. Review written Oct 22, 2026 from the project's own sources; usage data refreshed every Monday.

TL;DR

Logfire is an observability platform from the team behind Pydantic Validation, built as an opinionated wrapper around OpenTelemetry. It is for developers running LLM apps, agents, and Python services in production. What sets it apart: you query traces, logs, metrics, and eval results with standard SQL, and the Python SDK gives detailed visibility into Python code.

4.5kGitHub stars
+9new stars, week of Oct 25
~4.6Mdownloads a week, +16% vs 4-week avg
#11in Evals and observability this week

Logfire at a glance

Category: Evals and observability
Maintained by: Pydantic (organization, @pydantic on GitHub)
License: MIT
Language: Python, JavaScript, Makefile
Repository: github.com/pydantic/logfire
Website: pydantic.dev/logfire
npm package: @pydantic/logfire-node 0.18.30
PyPI package: logfire 5.2.0
Latest release: @pydantic/logfire-node 0.18.30 on npm, Oct 21, 2026
First published: Apr 23, 2024

What Logfire does

Logfire supports all OpenTelemetry signals: traces, metrics, and logs.
Logfire lets you query your data with standard SQL, including from existing BI tools and database querying libraries.
Logfire shows rich displays of Python objects, event-loop telemetry, and profiling of Python code and database queries.
Logfire traces LLM calls and costs, and stores eval results and prompt versions in the same table as traces.
Logfire auto-instruments popular packages such as FastAPI, so you can skip most manual instrumentation.
Logfire gives analytics on data flowing through Pydantic Validation models.

How it works

Logfire has open-source SDKs for Python, TypeScript, and Rust that send telemetry to the closed-source Logfire platform, which holds the UI and backend. Other languages connect through standard OpenTelemetry. You call logfire.configure() in your code, then add spans and logs or instrument libraries. The SDKs can also export to any OTel-compatible backend. Model calls routed through the AI Gateway land in Logfire without an SDK.

How to install and start using Logfire

With pip (SDK and CLI)

pip install logfire

With pip (SDK only)

pip install logfire-sdk

Set up with your coding agent

uvx logfire-cli wizard

Requirements

Python 3.10 or later for the Python SDK.
A Logfire account, authenticated with logfire auth, to send data to the hosted platform.
Self-hosting the platform requires purchasing an enterprise license.

First steps

Install Logfire with pip install logfire, which adds both the Python SDK and the CLI.
Authenticate by running logfire auth.
Call logfire.configure() in your code, then send logs with logfire.info() or wrap work in logfire.span().
Instrument frameworks instead of tracing manually, for example with logfire.instrument_fastapi(app).

Who Logfire is for

Teams running LLM apps and agents in production that need tracing, evals, and cost tracking.
Python developers, especially those using FastAPI, Pydantic, or Pydantic AI.
Teams that want to query telemetry with SQL or from existing BI tools.
Polyglot teams already using OpenTelemetry across languages.

Limitations to know

Logfire's platform, meaning the UI and backend, is closed source. Only the SDKs are open source.
Logfire can only be self-hosted with a purchased enterprise license.
Logfire has native SDKs only for Python, TypeScript, and Rust. Other languages rely on standard OpenTelemetry.
Logfire's zstd compression support is experimental as of v5.2.0.

Is Logfire growing? Usage data

In the week of Oct 25–31, 2026, Logfire ranked #226 on the Devtoolwatch Board and #11 in Evals and observability, with a momentum score of 41 out of 100. Its main package had about 4.6M downloads that week, +16% against its own 4-week average.

New GitHub stars per week for the last 12 weeks, from GitHub's stargazer history (today's stargazers by the week they starred).

Show the weekly numbers

New GitHub stars per week for Logfire
Week of	New stars
Aug 9, 2026	13
Aug 16, 2026	6
Aug 23, 2026	14
Aug 30, 2026	11
Sep 6, 2026	17
Sep 13, 2026	7
Sep 20, 2026	15
Sep 27, 2026	13
Oct 4, 2026	5
Oct 11, 2026	12
Oct 18, 2026	5
Oct 25, 2026	9

On Hacker News

The human-in-the-loop is tired, 318 points and 200 comments (Jul 17, 2026)
Pydantic Logfire, 146 points and 79 comments (Apr 30, 2024)
Pydantic V2 rewritten in Rust is 5-50x faster than Pydantic V1, 137 points and 36 comments (Apr 8, 2023)
Shredding JSON columns gave Logfire up to 1000x faster queries, 29 points and 29 comments (Oct 11, 2026)
Logfire – OpenTelemetry based tracing SaaS, 14 points and 0 comments (Sep 14, 2025)

The Board ranks tools by four signals each week: new stars, new stars for the repo's size, added downloads and download growth beyond the market. How the ranking works.

Logfire alternatives

Other LLM evals and observability tools on the Board in the week of Oct 25–31, 2026, by momentum:

Evals and observability ranked by momentum, the week of Oct 25–31, 2026
Rank	Tool	Stars	Downloads/wk
#1	SkillSpectorSkillSpector is NVIDIA's security scanner that checks AI agent skills for vulnerabilities, malicious patterns, and supply-chain risks…	23.7k	–
#2	JudgevalJudgeval is an open-source Python SDK for tracing and evaluating LLM-powered agents with prompt-based judges and online monitoring.	1.1k	80.2k
#3	A.I.G (AI-Infra-Guard)A full-stack AI Red Teaming platform securing AI ecosystems via Agent Scan, Skills Scan, MCP scan, AI Infra scan and LLM jailbreak…	7.2k	–
#4	LangfuseLangfuse is an open source LLM engineering platform for tracing, evaluating, prompt management, and debugging LLM applications and agents.	36.8k	9.8M
#5	OpikOpik is an open-source platform from Comet for tracing, evaluating, and monitoring LLM applications, RAG systems, and AI agents.	23.1k	709.1k
#6	promptfoopromptfoo is a CLI and library for evaluating and red-teaming LLM-based apps, including prompts, agents, and RAG pipelines.	26.7k	1.2M

All LLM evals and observability tools, ranked

Recent Logfire releases

v5.2.0, Oct 13, 2026
v6.0.0b8 (pre-release), Oct 10, 2026
v6.0.0b7 (pre-release), Sep 25, 2026
v5.1.1, Sep 25, 2026
v6.0.0b6 (pre-release), Sep 25, 2026

Logfire FAQ

Is Logfire free and open source?

Yes. Logfire's source code is on GitHub (pydantic/logfire) under the MIT license, so you can use it for free. Its website also links to a pricing page (https://pydantic.dev/pricing) for any paid plans.

How do I install Logfire?

Run pip install logfire. The install section above has the other options from the project's README.

Is Logfire still maintained?

Yes. The pydantic/logfire repository was last updated on Oct 22, 2026, and the latest release, @pydantic/logfire-node 0.18.30 on npm, came out on Oct 21, 2026.

How popular is Logfire?

Logfire has 4.5k GitHub stars as of Nov 1, 2026. It gained 9 new stars in the week of Oct 25–31, 2026, against a 12-week average of 11 a week. Its main package had about 4.6M downloads that week, +16% against its own 4-week average. That made it #11 among LLM evals and observability tools on the Devtoolwatch Board.

Logfire vs Langfuse: how do they compare?

Logfire and Langfuse are both tracked by Devtoolwatch as LLM evals and observability tools. Logfire has 4.5k GitHub stars and Langfuse has 36.8k. In the week of Oct 25–31, 2026, Logfire's main package had 4.6M downloads and Langfuse's had 9.8M. Langfuse is an open source LLM engineering platform for tracing, evaluating, prompt management, and debugging LLM applications and agents. Langfuse review.

What are the best alternatives to Logfire?

Other LLM evals and observability tools on the Devtoolwatch Board in the week of Oct 25–31, 2026, by momentum: SkillSpector (#1), Judgeval (#2), A.I.G (AI-Infra-Guard) (#3), Langfuse (#4), Opik (#5). The alternatives table above has their numbers.

What is Pydantic Logfire used for?

Logfire is used for observability of LLM apps, agents, APIs, and general applications. It covers distributed tracing, logs, metrics, evals, and cost tracking. You can query all of this data with SQL.

Is Logfire open source?

Logfire is partly open source. The SDKs for Python, TypeScript, and Rust are open source. The platform, meaning the UI and backend, is closed source.

Can I use the Logfire SDK with an alternative backend?

Yes. The open-source Logfire SDKs can export data to any OTel-compatible backend, so you are not tied to the Logfire platform.

How do I use Pydantic Logfire in Python?

Install Logfire with pip install logfire and run logfire auth. Then call logfire.configure() in your code and use logfire.info() or logfire.span(). You can also instrument a framework, for example with logfire.instrument_fastapi(app).

Is there a free tier for Logfire?

Yes. The Logfire homepage lists 10 million spans free every month, with no credit card needed.

Sources

Logfire README badge

Maintainers can show the tool's weekly Board rank in their README:

[![Devtoolwatch](https://index.devtoolwatch.com/badge/logfire.svg)](https://index.devtoolwatch.com/tools/logfire/)

How this page is made: Devtoolwatch writes each review from the project's README, releases, package metadata and website, with an AI model, then checks every claim against the source it cites and drops what the sources don't support. The numbers come from Devtoolwatch's daily GitHub snapshots, GitHub's stargazer history, and the npm and PyPI download APIs. Spotted an error? Email [email protected].