5 WordPress Hook Bugs Every Developer Makes (And How to Fix Them)

If you’ve spent any time building WordPress themes or plugins, you’ve definitely been in this frustrating situation: “My code is perfect. Why on earth isn’t this function running?”

Most of the time, your logic isn’t the problem—your hook timing is. WordPress relies entirely on an event-driven architecture (actions and filters). If you attach your code to the wrong hook, or set the wrong priority, things break. Fast.

Today, we’re looking at the 5 most common WordPress hook mistakes developers make, and how to fix them. Best of all? At the end of this post, I’ve included a custom WordPress hook order checker tool so you never have to guess when a hook fires again.

1. Setting Cookies or Redirects on init

It’s tempting for newer developers to just throw everything onto the init hook. But if you try to trigger a page redirect or set a cookie here, you’ll often get slapped with the dreaded “Headers already sent” error.

• The Mistake: Hooking redirects at init.
• The Fix: Whenever you need to redirect a user or set cookies, hook into template_redirect instead. At this point, WordPress has loaded the core configurations, but hasn’t started sending output to the browser yet.

2. The save_post Infinite Loop (A Server Killer)

When you use the save_post hook to modify post data and then call wp_update_post inside your function, guess what happens? wp_update_post triggers save_post all over again. Congratulations, you just built an infinite loop that will crash your site.

• The Fix: Before you update the post, remove your hook using remove_action(). Run your update, and then reattach it with add_action(). This breaks the cycle.

3. Forgetting Logged-out Users in AJAX

When handling custom AJAX calls outside the dashboard, developers often just register wp_ajax_{action} and call it a day. Then they wonder why the form works fine when they are logged in, but fails completely for site visitors.

• The Fix: Always register wp_ajax_nopriv_{action} alongside your main hook if you want guest users to actually be able to run that AJAX function.

4. Enqueuing Scripts on admin_init

It sounds logical, right? You want to load CSS or JS in the admin area, so you use admin_init. Unfortunately, this is unpredictable and can cause your assets to leak into screens where they don’t belong, causing conflicts.

• The Fix: Always use the admin_enqueue_scripts hook for backend assets. It even passes a $hook_suffix parameter, letting you limit your scripts to very specific admin pages.

5. Not Checking the Query on pre_get_posts

If you want to modify the main query on the frontend (like changing the number of posts per page), pre_get_posts is your best friend. But if you don’t use the is_main_query() check, your filter will accidentally apply to sidebars, navigation menus, and even admin dashboard queries.

• The Fix: Always start your custom query logic with a safety check: if( ! $query->is_main_query() || is_admin() ) return;

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🚀 Try the WordPress Hook Order Checker Tool

To figure out exactly which hook runs first and where you should inject your code, I built a completely free, interactive tool for the community. Using this WordPress hook order checker, you can visually track when hooks fire across Core WordPress, WooCommerce, and ACF. No more guessing.

👉 Click Here To Use The Tool in Full Screen

Or try it directly below:

Bookmark this page for the next time you’re stuck on a weird hook execution sequence. Happy coding!