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Pydantic Logfire

by pydanticPython

Uncomplicated observability and tracing built on OpenTelemetry.

Toolstable

Maturity: stable because 2y old, v4.39.0 released 10d ago. Derived from release and commit history, not a rating.

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4.4k
Forks
269
Downloads / mo
Last commit
2026-08-03
License
MIT
Open issues
254

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In practice

Written by AI from this repository’s README · high confidence

Provides telemetry and SQL-based querying for Python applications and Pydantic models.

Use it when

Use to monitor and trace LLM applications and complex Pydantic data flows.

Not the right pick when

Requires a paid cloud service for the backend UI unless exporting to alternative OTel backends.

Capabilities

  • Python-centric Insights
  • SQL data querying
  • OpenTelemetry wrapper
  • Pydantic Integration

Cost: Open source with a paid cloud option

Video walkthroughs

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What the repository ships

Ships CLAUDE.mdHas testsHas docsHas examplesCI configured

Detected from the actual files in the repository root.

Latest release v4.39.0

Published 2026-07-24

  • httpx2 support in logfire.instrument_httpx() by @alexmojaki in #2095
  • Support OpenTelemetry SDK 1.44.0 by @alexmojaki in #2094

Tags

README

Pydantic Logfire: Know more. Build faster.

<p align="center">

<a href="https://github.com/pydantic/logfire/actions?query=event%3Apush+branch%3Amain+workflow%3ACI"><img src="https://github.com/pydantic/logfire/actions/workflows/main.yml/badge.svg?event=push" alt="CI" /></a>

<a href="https://codecov.io/gh/pydantic/logfire"><img src="https://codecov.io/gh/pydantic/logfire/graph/badge.svg?token=735CNGCGFD" alt="codecov" /></a>

<a href="https://pypi.python.org/pypi/logfire"><img src="https://img.shields.io/pypi/v/logfire.svg" alt="pypi" /></a>

<a href="https://github.com/pydantic/logfire/blob/main/LICENSE"><img src="https://img.shields.io/github/license/pydantic/logfire.svg" alt="license" /></a>

<a href="https://github.com/pydantic/logfire"><img src="https://img.shields.io/pypi/pyversions/logfire.svg" alt="versions" /></a>

<a href="https://pydantic.dev/docs/logfire/join-slack/"><img src="https://img.shields.io/badge/Slack-Join%20Slack-4A154B?logo=slack" alt="Join Slack" /></a>

</p>

From the team behind Pydantic Validation, Pydantic Logfire is an observability platform built on the same belief as our open-source library: that the most powerful tools can be easy to use.

What sets Logfire apart:

  • Simple and Powerful: Logfire's dashboard is simple relative to the power it provides, ensuring your entire engineering team will actually use it.
  • Python-centric Insights: From rich display of Python objects, to event-loop telemetry, to profiling Python code and database queries, Logfire gives you unparalleled visibility into your Python application's behavior.
  • SQL: Query your data using standard SQL: all the control and (for many) nothing new to learn. Using SQL also means you can query your data with existing BI tools and database querying libraries.
  • OpenTelemetry: Logfire is an opinionated wrapper around OpenTelemetry, allowing you to leverage existing tooling, infrastructure, and instrumentation for many common Python packages, and enabling support for virtually any language. We offer full support for all OpenTelemetry signals (traces, metrics and logs).
  • Pydantic Integration: Understand the data flowing through your Pydantic Validation models and get built-in analytics on validations.

See the documentation for more information.

Feel free to report issues and ask any questions about Logfire in this repository!

This repo contains the Python SDK for logfire and documentation; the server application for recording and displaying data is closed source.

Using Logfire

This is a very brief overview of how to use Logfire, the documentation has much more detail.

Install


pip install logfire

_(learn more)_

Authenticate


logfire auth

_(learn more)_

Manual tracing

Here's a simple manual tracing (aka logging) example:


from datetime import date

import logfire

logfire.configure()
logfire.info('Hello, {name}!', name='world')

with logfire.span('Asking the user their {question}', question='age'):
    user_input = input('How old are you [YYYY-mm-dd]? ')
    dob = date.fromisoformat(user_input)
    logfire.debug('{dob=} {age=!r}', dob=dob, age=date.today() - dob)

_(learn more)_

Integration

Or you can also avoid manual instrumentation and instead integrate with lots of popular packages, here's an example of integrating with FastAPI:


from fastapi import FastAPI
from pydantic import BaseModel

import logfire

app = FastAPI()

logfire.configure()
logfire.instrument_fastapi(app)
# next, instrument your database connector, http library etc. and add the logging handler


class User(BaseModel):
    name: str
    country_code: str


@app.post('/')
async def add_user(user: User):
    # we would store the user here
    return {'message': f'{user.name} added'}

_(learn more)_

Logfire gives you a view into how your code is running like this:

Logfire screenshot

Contributing

We'd love anyone interested to contribute to the Logfire SDK and documentation, see the contributing guide.

Reporting a Security Vulnerability

See our security policy.

Logfire Open-Source and Closed-Source Boundaries

The Logfire SDKs (we also have them for TypeScript and Rust) are open source, and you can use them to export data to any OTel-compatible backend.

The Logfire platform (the UI and backend) is closed source. You can self-host it by purchasing an enterprise license.

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