Building a WordPress plugin that passes WordPress.org review is harder than it looks. Here's what we actually learned going through the process of building and submitting Equipment Rental System.
1. The WordPress review team is thorough
The WordPress.org plugin review process checks for security issues, coding standards, and proper use of WordPress APIs. It's not just a rubber stamp. Plan for at least one revision cycle.
2. Sanitise everything, escape everything
Every piece of user input must be sanitised before saving and escaped before output. WordPress provides functions for this — use them. Reviewers will catch anything you miss.
3. Use WordPress nonces for form security
Any form submission or AJAX call needs a nonce. This protects against CSRF attacks and is a hard requirement for WordPress.org approval.
4. Prefix everything
Functions, classes, database table names, option names — everything must be prefixed to avoid conflicts with other plugins. We use ers_ throughout Equipment Rental System.
5. Test with Query Monitor active
Query Monitor is a free plugin that shows you every database query, hook, and error your plugin triggers. Running it during development saved us from several N+1 query bugs before they made it to production.
