# qos-ch/logback

The reliable, generic, fast and flexible logging framework for Java.

Repository: https://github.com/qos-ch/logback
Canonical: https://ross.abutalabs.com/products/logback
Homepage: http://logback.qos.ch
Language: Java
License: NOASSERTION
License Family: other
Last push: 2026-08-25T14:54:29+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 98, longevity 100
- inputs: {"age_days": 6222, "days_push": 8, "days_rel": 19, "gap_med": 11.0, "n_releases_24m": 27}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3233, forks 1364 (observed 2026-08-28T04:07:50.222131+00:00)

## What it is
Logback is a reliable, fast and flexible logging framework for Java, intended as the successor to log4j 1.x. It natively implements the SLF4J API and is divided into logback-core, logback-classic, and logback-access modules.

## Use cases
- add structured logging to a Java application
- replace log4j 1.x with a maintained logging framework
- implement SLF4J logging in a Spring Boot service
- capture HTTP access logs in Tomcat or Jetty
- configure rolling log files and log levels
- switch logging backends without changing application code

## When to choose
- you need a mature, widely adopted SLF4J-native logging implementation for the JVM
- you are migrating away from log4j 1.x or java.util.logging
- you need flexible configuration of appenders, filters, and rolling policies

## When to avoid
- you are not on the JVM or need logging for another language
- you need a minimal zero-dependency logging facade only (SLF4J alone may suffice)
- you require async-first structured logging with JSON output out of the box (consider Log4j2 or dedicated structured loggers)

## Facets
- artifact type: library
- maturity: stable
- function: logging
- domain: developer-tools, backend, monitoring
- platform: jvm, cross-platform
- tags: slf4j, log4j-successor, java-logging

## Member repositories
- qos-ch/logback (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:50.222131+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:43:56.359620+00:00, confidence not recorded.
  - readme: https://github.com/qos-ch/logback (fetched 2026-08-28T04:07:50.222131+00:00, sha bef7b9036105)
  - homepage: http://logback.qos.ch (fetched 2026-08-29T09:37:35.012839+00:00, sha 95c15a44ecc7)
- Data as of 2026-08-30T08:39:29.467469+00:00.