Configuration

CostCutter's behavior is fully customizable through configuration files, environment variables, and CLI arguments.

How Configuration Works

Configuration is loaded from multiple sources in a strict precedence order. Higher precedence sources override lower ones.

flowchart TB
    CLI["CLI Arguments"]
    ENV["Environment Variables<br/>(COSTCUTTER_* prefixed)"]
    PROJECT["Project Config<br/>(costcutter.yaml in current directory)"]
    GLOBAL["Global Config<br/>(~/.config/costcutter/config.toml)"]
    DEFAULTS["Defaults<br/>(built-in safe defaults)"]

    CLI --> ENV --> PROJECT --> GLOBAL --> DEFAULTS

Configuration File Locations

CostCutter searches for configuration files in the following locations:

You can also specify an explicit config file:

costcutter --config /path/to/my-config.yaml

Supported Formats

CostCutter supports three configuration file formats:

• YAML - .yaml or .yml
• TOML - .toml
• JSON - .json

All formats support the same configuration options. See File Formats for complete examples.

Quick Example

A minimal configuration file:

# costcutter.yaml
dry_run: true

aws:
  profile: dev
  region:
    - us-east-1
  services:
    - ec2
    - s3

What Can Be Configured?

See the Configuration Reference for all available options.

Environment Variables

Every configuration option can be overridden via environment variables:

• Prefix: COSTCUTTER_
• Nested values: Use double underscores (__)

Examples:

# Top-level setting
export COSTCUTTER_DRY_RUN=false

# Nested setting
export COSTCUTTER_AWS__PROFILE=staging
export COSTCUTTER_AWS__REGION='["us-east-1", "eu-west-1"]'
export COSTCUTTER_LOGGING__LEVEL=DEBUG

-> Next: File Formats | Reference