structlog 25.4.0

Structured Logging for Python

structlog is the production-ready logging solution for Python:

• Simple: Everything is about functions that take and return dictionaries – all hidden behind familiar APIs.
• Powerful: Functions and dictionaries aren’t just simple but also powerful. structlog leaves you in control.
• Fast: structlog is not hamstrung by designs of yore. Its flexibility comes not at the price of performance.

Thanks to its flexible design, you choose whether you want structlog to take care of the output of your log entries or whether you prefer to forward them to an existing logging system like the standard library's logging module.

The output format is just as flexible and structlog comes with support for JSON, logfmt, as well as pretty console output out-of-the-box:

Sponsors

structlog would not be possible without our amazing sponsors. Especially those generously supporting us at the The Organization tier and higher:

Please consider joining them to help make structlog’s maintenance more sustainable!

Introduction

structlog has been successfully used in production at every scale since 2013, while embracing cutting-edge technologies like asyncio, context variables, or type hints as they emerged. Its paradigms proved influential enough to help design structured logging packages across ecosystems.

Project Links

• Get Help (use the structlog tag on Stack Overflow)
• PyPI
• GitHub
• Documentation
• Changelog
• Third-party Extensions

structlog for Enterprise

Available as part of the Tidelift Subscription.

The maintainers of structlog and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source packages you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact packages you use.

Release Information

Added

• Support for Python 3.14 and Python 3.13.4.

  Python 3.14 has an backwards-incompatible change to logging.Logger.isEnabledFor() (it now always returns False if a log entry is in flight) that has been backported to 3.13.4 (expected on 2025-06-03). It mainly affects structlog.stdlib.filter_by_level(). #723

• structlog.tracebacks now handles exception groups. structlog.tracebacks.Stack has two new fields, is_group: bool and exceptions: list[Trace]. This works similarly to what Rich v14.0.0 does. #720

Fixed

• structlog.processors.ExceptionPrettyPrinter now respects the exception_formatter arguments instead of always using the default formatter. #724

---

Full Changelog →

Credits

structlog is written and maintained by Hynek Schlawack. The idea of bound loggers is inspired by previous work by Jean-Paul Calderone and David Reid.

The development is kindly supported by my employer Variomedia AG, structlog’s Tidelift subscribers, and all my amazing GitHub Sponsors.

The logs-loving beaver logo has been contributed by Lynn Root.