# spf13/viper

Go configuration with fangs

Repository: https://github.com/spf13/viper
Canonical: https://ross.abutalabs.com/products/viper
Language: Go
License: MIT
License Family: permissive
Last push: 2026-01-12T21:42:47+00:00

## Health v2 (maintenance only)
Score: 60/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 62, release rhythm 35, longevity 100
- inputs: {"age_days": 4536, "days_push": 233, "days_rel": 359, "gap_med": 88.0, "n_releases_24m": 3}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 30447, forks 2284 (observed 2026-08-28T04:11:54.470452+00:00)

## What it is
Viper is a comprehensive configuration library for Go applications that reads from files, environment variables, command-line flags, and remote key-value stores like Etcd and Consul. It supports defaults, key aliasing, and live watching of configuration changes, serving as a central registry for all app configuration needs.

## Use cases
- manage configuration for a go application
- read config from yaml json and toml files
- load settings from environment variables
- watch config files for live changes
- merge configuration from multiple sources
- read remote config from consul or etcd
- build 12-factor apps in go

## When to choose
- you need a unified configuration solution across files, env vars, flags, and remote stores in Go
- you want live config reloading without restarting your app
- you need support for many config file formats out of the box

## When to avoid
- you need only simple single-file config parsing and want a minimal dependency
- you are not writing Go
- you need strongly typed config validation beyond what Viper offers

## Facets
- artifact type: library
- maturity: stable
- function: configuration-management, developer-tools
- domain: developer-tools, backend, apis
- platform: go, cross-platform
- tags: config-files, environment-variables, 12-factor-apps, live-reload, yaml, json, toml, consul, etcd

## Member repositories
- spf13/viper (main) score 60

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:54.470452+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 2026-08-29T16:52:45.965581+00:00, confidence not recorded.
  - readme: https://github.com/spf13/viper (fetched 2026-08-28T04:11:54.470452+00:00, sha 5493a9108adb)
- Data as of 2026-08-30T08:39:29.467469+00:00.