PHP GOBL Validator

A PHP library for validating JSON against GOBL schemas without requiring the GOBL CLI.

Installation

composer require ecourier/gobl-validator

Usage

The validator accepts both JSON strings and objects.

Basic Validation

The validate() method auto-detects the schema from the $schema property in your data:

use Ecourier\GoblValidator\GoblValidator;

$validator = new GoblValidator();

// Validate a JSON string
$invoiceJson = '{"$schema": "https://gobl.org/draft-0/bill/invoice", ...}';
$validator->validate($invoiceJson);

// Validate an object
$invoiceObject = json_decode($invoiceJson);
$validator->validate($invoiceObject);

Supported Root Schemas

The validator supports these root document types:

• envelope - https://gobl.org/draft-0/envelope
• invoice - https://gobl.org/draft-0/bill/invoice
• order - https://gobl.org/draft-0/bill/order

Validate Envelope

Use validateEnvelope() to explicitly validate against the envelope schema:

$validator->validateEnvelope($envelopeJson);

Handling Validation Errors

When validation fails, a GoblValidationException is thrown containing the validation error details.

Using getFormattedErrors() (Recommended)

The getFormattedErrors() method provides clean, user-friendly error messages:

use Ecourier\GoblValidator\GoblValidator;
use Ecourier\GoblValidator\Exceptions\GoblValidationException;
use Ecourier\GoblValidator\Exceptions\InvalidSchemaException;

$validator = new GoblValidator();

try {
    $validator->validate($data);
} catch (InvalidSchemaException $e) {
    // The $schema property is not a supported root schema
    echo $e->getMessage();
} catch (GoblValidationException $e) {
    // Get formatted errors as an associative array (path => messages)
    $errors = $e->getFormattedErrors();
    print_r($errors);
    // Example output:
    // [
    //     '/currency' => ['The value "INVALID" is not a valid option'],
    //     '/supplier/tax_id/country' => ['The value "XX" is not a valid option'],
    //     '/customer/tax_id/country' => ['The value "YY" is not a valid option'],
    // ]
}

Benefits of getFormattedErrors():

• Returns all errors - Validates the entire document and returns all validation failures, not just the first one
• Consolidates enum errors - Country codes, currency codes, and similar enum-like schemas return a single meaningful error instead of hundreds of "const mismatch" messages
• Filters false positives - Removes misleading "Unknown properties" errors that can appear at ancestor paths when nested validation fails
• Clean paths - Uses JSON Pointer-style paths like /customer/tax_id/country

Using Opis ErrorFormatter (Advanced)

For more control over error formatting, you can use the raw validationError property with Opis's ErrorFormatter:

use Opis\JsonSchema\Errors\ErrorFormatter;

try {
    $validator->validate($data);
} catch (GoblValidationException $e) {
    if ($e->validationError) {
        $formatter = new ErrorFormatter();
        
        // Get errors as an associative array (path => errors)
        $errors = $formatter->format($e->validationError);
        
        // Or get a flat list of error messages
        $flatErrors = $formatter->formatFlat($e->validationError);
        
        // Get detailed error information
        $detailedErrors = $formatter->formatOutput($e->validationError, 'detailed');
    }
}

Note: The raw ErrorFormatter will show all sub-errors including hundreds of individual "const mismatch" errors for enum-like fields. Use getFormattedErrors() for cleaner output.

Limitations

This library performs JSON Schema validation only. It does not replace the GOBL CLI or API for full document validation.

What this library validates:

• Required fields (e.g., type, issue_date, currency, supplier, totals)
• Data types (strings, numbers, arrays, objects)
• Field formats (UUIDs, dates, country codes, currency codes)
• Enum values (invoice types, tax categories)
• Unknown properties (typos like customer2 instead of customer)

What this library does NOT validate:

• Business rules (e.g., customer required for standard invoices)
• Tax calculations (e.g., totals matching line sums)
• Regime-specific requirements (e.g., Spanish TicketBAI, French Factur-X)
• Addon-specific validation rules
• Cross-field validation logic

For complete validation including business rules, use the GOBL CLI or the GOBL API.

This library is ideal for:

• Quick structural validation in PHP applications
• Unit testing generated GOBL documents
• Catching common errors before sending to GOBL

GOBL Version

The bundled schemas are derived from GOBL version:

echo GoblValidator::$GOBL_VERSION; // e.g., "0.303.0"

License

This library is licensed under the MIT License.

The bundled GOBL schemas (in the schemas/ directory) are © Invopop Ltd and licensed under the Apache License 2.0. See the GOBL repository for more information.