Configuration that stays in sync

maxicfg is a single-binary command-line tool that validates configuration files against a schema, renders templates, and reports drift between environments before it reaches production.

Go 1.22+ MIT licensed YAML · TOML · JSON · dotenv no runtime dependencies

Install Read the docs

Quick start

Validate every configuration file in a directory against its schema:

$ maxicfg lint ./config --schema ./config/schema.yaml
config/production.yaml  ok
config/staging.yaml     ok
config/local.yaml       2 problems

  local.yaml:14:3  unknown key "databse.pool_size" (did you mean "database"?)
  local.yaml:31:1  required key "logging.level" is missing

1 of 3 files failed

Compare two environments and see only what actually differs:

$ maxicfg diff config/staging.yaml config/production.yaml --ignore-secrets

~ database.pool_size    10 -> 40
~ cache.ttl             5m -> 1h
+ features.new_billing  true          (only in production)
- debug.profiler        true          (only in staging)

4 differences, 27 keys identical

Schema validation

Catch typos, missing keys and wrong types before deploy, not after.

Drift detection

Compare environments and surface configuration that silently diverged.

Templating

Render configs from templates with environment variables and defaults.

Secret scanning

Flag credentials accidentally committed into configuration files.

Why another config tool

Most projects end up with a handful of near-identical configuration files — one per environment — that slowly drift apart. A key gets added to staging and never makes it to production. A value gets tuned during an incident and nobody writes it down. Six months later nobody can say which file is correct.

maxicfg does not try to replace your configuration management. It reads the files you already have, tells you where they disagree, and fails the build when something looks wrong. That is the whole scope.

Status: maxicfg is pre-1.0. The command-line interface is stable in practice, but flags may still change between minor versions. Pin a version in CI — see installation.