Config Format Converter#

Universal configuration file format converter for JSON, YAML, and TOML.

When to Use#

• Converting package.json to pyproject.toml or vice versa
• Migrating CI/CD configs between formats ( .yaml ↔ .json)
• Normalizing config files for cross-platform projects
• Validating syntax before committing config changes
• Pretty-printing minified config files

Supported Formats#

FormatExtensionsUse CasesJSON.jsonnpm, Node.js, VS Code settingsYAML.yaml, .ymlDocker Compose, GitHub Actions, KubernetesTOML.tomlPython Poetry, Rust Cargo, Go modules

Quick Start#

Convert Between Formats#

python

import json
import yaml
import toml

# JSON to YAML
with open('package.json') as f:
    data = json.load(f)
with open('package.yaml', 'w') as f:
    yaml.dump(data, f, default_flow_style=False, sort_keys=False)

# YAML to JSON
with open('docker-compose.yaml') as f:
    data = yaml.safe_load(f)
with open('docker-compose.json', 'w') as f:
    json.dump(data, f, indent=2)

# TOML to JSON
with open('pyproject.toml') as f:
    data = toml.load(f)
with open('pyproject.json', 'w') as f:
    json.dump(data, f, indent=2)

Validate Config Syntax#

python

import json
import yaml

def validate_json(filepath):
    try:
        with open(filepath) as f:
            json.load(f)
        return True, "Valid JSON"
    except json.JSONDecodeError as e:
        return False, str(e)

def validate_yaml(filepath):
    try:
        with open(filepath) as f:
            yaml.safe_load(f)
        return True, "Valid YAML"
    except yaml.YAMLError as e:
        return False, str(e)

Pretty-Print Configs#

python

import json

# Compact to pretty JSON
with open('config.min.json') as f:
    data = json.load(f)
with open('config.json', 'w') as f:
    json.dump(data, f, indent=2, ensure_ascii=False)

Common Workflows#

Migrate npm Project to Python Poetry#

python

import json
import toml

# Read package.json
with open('package.json') as f:
    pkg = json.load(f)

# Create pyproject.toml structure
pyproject = {
    'tool': {
        'poetry': {
            'name': pkg.get('name', ''),
            'version': pkg.get('version', '0.1.0'),
            'description': pkg.get('description', ''),
            'authors': [],
            'dependencies': {}
        }
    }
}

# Write TOML
with open('pyproject.toml', 'w') as f:
    toml.dump(pyproject, f)

Convert Docker Compose YAML to JSON for CI#

python

import yaml
import json

with open('docker-compose.yaml') as f:
    compose = yaml.safe_load(f)

with open('docker-compose.json', 'w') as f:
    json.dump(compose, f, indent=2)

Best Practices#

• Preserve comments: YAML/TOML comments are lost in conversion; document important notes separately
• Key ordering: Use sort_keys=False to preserve original key order
• Unicode: Always use ensure_ascii=False for international configs
• Validation: Always validate output after conversion
• Backup: Keep original files before bulk conversion

Error Handling#

Common issues and solutions:

IssueCauseFixScannerErrorInvalid YAML syntaxCheck indentation (spaces, not tabs)TomlDecodeErrorInvalid TOML syntaxVerify section headers [section]``JSONDecodeErrorTrailing commas in JSONRemove commas before } or ]Unicode errorsEncoding mismatchOpen files with encoding='utf-8'

Dependencies#

bash

pip install pyyaml toml