How to Fix Validation Error in PHP

Fixing Validation Errors in PHP

PHP validation errors occur when user input fails sanitization or type checks. Modern PHP frameworks provide validation systems, but raw PHP requires manual handling.

Common Issues

• filter_var returning false for invalid emails or URLs
• Missing required form fields
• Type coercion producing unexpected values

The Fix

Build a reusable validator:

<?php
class Validator {
    private array $errors = [];

    public function validate(array $data, array $rules): bool {
        foreach ($rules as $field => $fieldRules) {
            foreach ($fieldRules as $rule) {
                $value = $data[$field] ?? null;

                match($rule) {
                    'required' => $value === null || $value === ''
                        ? $this->addError($field, "$field is required") : null,
                    'email' => $value && !filter_var($value, FILTER_VALIDATE_EMAIL)
                        ? $this->addError($field, "$field must be a valid email") : null,
                    'numeric' => $value && !is_numeric($value)
                        ? $this->addError($field, "$field must be numeric") : null,
                };
            }
        }
        return empty($this->errors);
    }

    private function addError(string $field, string $msg): void {
        $this->errors[$field][] = $msg;
    }

    public function getErrors(): array { return $this->errors; }
}

Always validate on the server side regardless of client-side validation — never trust user input.

Bugsly for PHP

Bugsly tracks validation failures with the form or API endpoint context, letting you spot which inputs users struggle with most and improve your UX accordingly.