Validation

PrepArr validates all configuration using Zod schemas. Validation runs at startup and whenever the config file changes.

Common Validation Errors

Invalid API Key

API key must be exactly 32 characters and hexadecimal

API keys must be 32-character hexadecimal strings. Use --generate-api-key to create one:

docker run --rm ghcr.io/robbeverhelst/preparr:latest bun run dist/index.js --generate-api-key

Missing Required Fields

Configuration missing required field: rootFolders.0.path

Check that all required fields are present in your configuration file.

Invalid URL Format

SERVARR_URL must be a valid URL (e.g., http://sonarr:8989)

URLs must include the protocol (http:// or https://).

Type Mismatches

Expected number, received string at qualityProfiles.0.cutoff

Ensure numeric fields contain numbers, not quoted strings.

Testing Configuration

Use the validation endpoint to test your configuration before deploying:

curl -X POST http://preparr-sidecar:9001/validate \
  -H "Content-Type: application/json" \
  -d @sonarr-config.json

Valid response:

{
  "valid": true,
  "message": "Configuration is valid"
}

Invalid response:

{
  "valid": false,
  "errors": [
    {
      "path": ["qualityProfiles", 0, "cutoff"],
      "message": "Expected number, received string"
    }
  ]
}

Validating JSON Syntax

Before checking schema validation, make sure your JSON is syntactically valid:

# Check JSON syntax
python3 -m json.tool sonarr-config.json > /dev/null

# Or with jq
jq . sonarr-config.json > /dev/null

Common JSON syntax issues:

• Trailing commas after the last item in arrays or objects
• Single quotes instead of double quotes
• Unquoted keys
• Comments (JSON does not support comments)