Let’s separate WordPress developers into three levels.
WordPress developer level 1:
WordPress frontend developer
Those with the necessary experience utilizing pre-existing themes and plugins: Therefore, if you have someone with good expertise in customizing and merging to handle the project, it will go very well. They should have knowledge of HTML, CSS, and JavaScript as well as the ecosystem of WordPress plugins and themes.
WordPress developer level 2:
Junior Backend / Fullstack developer
You may rely on them to alter the themes and plugins by developing child themes and utilizing code snippets to complete some minor backend jobs since they will complete all the level 1 skills with PHP & MySQL and higher JavaScript abilities.
WordPress developer level 3:
Senior WordPress / Full stack developers
You will require the third level if you are working on large, complex projects, integrating 3rd party systems, designing themes or plugins from scratch, deeply enhancing the speed of your website, or dealing with databases.
Choose the right WordPress developer
You should focus more on their design abilities than anything else when asking someone whether they can create portfolio websites. Avoid anyone who utilizes Divi or Elementor, and make sure they know a little about HTML and CSS.
Many “devs” use theme builders, however, they are unable to add custom functions or do other tasks that aren’t already ‘baked in’ to the builder. If you need someone to build complicated websites, memberships, events, bookings, e-commerce, etc., make sure they are familiar with PHP and maybe JS.
Make sure they are familiar with REST APIs if you want the site to interface with other sites or platforms (for example, to integrate with another platform or to get feeds from another site).
It might be wise to inquire if they are skilled in the new FSE/Blocks methodology that WP is creating.
Ask them to demonstrate their favorite “trick” or talent related to WordPress if you want to get a solid idea of their abilities. You may use your ignorance to your advantage as those who are genuinely talented can explain complex ideas simply.
Job advertising for WordPress developers frequently gets applications from non-developers. Put up a stack that you want to be noticed.
Ask for the number of tables in the default WordPress installation. This eliminates around 75–85% of candidates. Since nobody would typically be aware of this, the next question is to name as many tables as you can. Even non-WP developers can provide a table structure.