# qos-ch/slf4j

Simple Logging Facade for Java

Repository: https://github.com/qos-ch/slf4j
Canonical: https://ross.abutalabs.com/products/slf4j
Homepage: http://www.slf4j.org
Language: Java
License: MIT
License Family: permissive
Last push: 2026-08-25T14:57:33+00:00

## Health v2 (maintenance only)
Score: 82/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 51, longevity 100
- inputs: {"age_days": 6222, "days_push": 8, "days_rel": 113, "gap_med": 440, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2519, forks 1024 (observed 2026-08-28T04:06:58.218640+00:00)

## What it is
SLF4J is a simple facade/abstraction for various Java logging frameworks such as java.util.logging, logback, log4j 2.x, reload4j, and tinylog. It lets end users plug in the desired logging framework at deployment time while libraries code against a single stable API.

## Use cases
- decouple library logging from a specific logging framework
- switch logging backends at deployment time without code changes
- avoid classpath conflicts from multiple logging APIs in Java projects
- migrate legacy commons-logging or log4j code to a unified API
- add logging to a Java library with a single mandatory dependency

## When to choose
- you write Java libraries that should work with any logging backend
- you want to standardize logging APIs across a multi-module project
- you need a no-operation default when no binding is present

## When to avoid
- you want a full logging implementation rather than a facade
- you work outside the JVM ecosystem
- you need structured logging features provided directly by a backend

## Facets
- artifact type: library
- maturity: stable
- function: logging
- domain: developer-tools, backend
- platform: jvm
- tags: logging-facade, abstraction, logback, java

## Member repositories
- qos-ch/slf4j (main) score 82

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:58.218640+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 2026-08-30T02:26:07.405582+00:00, confidence not recorded.
  - readme: https://github.com/qos-ch/slf4j (fetched 2026-08-28T04:06:58.218640+00:00, sha ea409aa0a2a9)
  - homepage: http://www.slf4j.org (fetched 2026-08-29T10:08:15.693454+00:00, sha 7eb9b9a5d681)
- Data as of 2026-08-30T08:39:29.467469+00:00.