Getting Started¶

About Pydantic Logfire¶

From the team behind Pydantic Validation, Pydantic Logfire is a new type of observability platform built on the same belief as our open source library — that the most powerful tools can be easy to use.

Logfire is built on OpenTelemetry, with native SDKs for Python, JavaScript/TypeScript, and Rust — plus support for any language via OpenTelemetry. Read more.

Overview¶

This page walks through setting up a Python app. For other languages, see the JavaScript/TypeScript integration or our language support page.

Set up Logfire
Install the SDK
Instrument your project

Set up Logfire¶

Log into Logfire
Follow the prompts to create your account
Once logged in, you'll see the Welcome to Logfire prompt. Click Let's go! to go to the starter-project Setup page.
You will find how to send data to your starter-project there. Also, there are some code snippets to help you get started.

A Logfire project is a namespace for organizing your data. All data sent to Logfire must be associated with a project.

Ready to create your own projects in UI or CLI?

In the UI, create projects by navigating to the Organization > Projects page, and click New project.
For CLI check the SDK CLI documentation.

Install the SDK¶

In the terminal, install the Logfire SDK (Software Developer Kit):

pipuvconda

pip install logfire

uv add logfire

conda install -c conda-forge logfire

Once installed, try it out!

logfire -h

Next, authenticate your local environment:

logfire auth

Upon successful authentication, credentials are stored in ~/.logfire/default.toml.

Instrument your project¶

Development Production

Development setup

During development, we recommend using the CLI to configure Logfire. You can also use a write token.

Set your project

in the terminal:

logfire projects use <first-project>

Run this command from the root directory of your app, e.g. ~/projects/first-project

Write some basic logs in your Python app

hello_world.py

import logfire

logfire.configure()  # (1)!
logfire.info('Hello, {name}!', name='world')  # (2)!

The configure() method should be called once before logging to initialize Logfire.
This will log Hello world! with info level.

Other log levels are also available to use, including trace, debug, notice, warn, error, and fatal.

See your logs in the Live view

Production setup

In production, we recommend you provide your write token to the Logfire SDK via environment variables.

Generate a new write token in the Logfire platform
- Go to Project Settings Write Tokens
- Follow the prompts to create a new token
Configure your Logfire environment

In the terminal:

export LOGFIRE_TOKEN=<your-write-token>

Running this command stores a Write Token used by the SDK to send data to a file in the current directory, at .logfire/logfire_credentials.json

Write some basic logs in your Python app

hello_world.py

import logfire

logfire.configure()  # (1)!
logfire.info('Hello, {name}!', name='world')  # (2)!

The configure() method should be called once before logging to initialize Logfire.
This will log Hello world! with info level.

Other log levels are also available to use, including trace, debug, notice, warn, error, and fatal.

See your logs in the Live view

Next steps¶

Ready to keep going?

Read about Concepts
Complete the Onboarding Checklist
Building AI applications? See AI & LLM Observability