Case Studies QueueForge: deferring heavy scripts to fix INP
QueueForge: deferring heavy scripts to fix INP
TL;DR Heavy scripts that run on load keep the main thread busy, so the first tap feels slow and INP suffers. QueueForge holds non-essential JavaScript until the visitor first interacts, then releases it. The page becomes responsive sooner without losing any functionality.
INP, Interaction to Next Paint, punishes a page that is too busy to answer the first tap. The usual culprit is JavaScript that insists on running the moment the page loads, even though nobody needs it yet. QueueForge is my answer to that: hold the heavy stuff back until the visitor actually does something.
The problem
A typical WordPress page pulls in scripts for analytics, chat widgets, social embeds, sliders, and more. Many of them run on load. While they run, the main thread is occupied, so when a visitor taps a menu in that window, the browser cannot respond right away. That delay is exactly what INP records, and a single bad interaction can sink the score.
The frustrating part is that most of those scripts do not need to run at load at all. A chat widget can wait until someone wants to chat. Analytics can wait a beat. They just default to running immediately because that is the easy way to enqueue them.
The approach
The idea is simple to state and fiddly to do well: defer non-essential JavaScript until the first user interaction, then let it run.
- Queue, do not drop. Nothing is removed. The scripts still run, just slightly later, once the page is responsive.
- Release on first interaction. A scroll, tap, key, or mouse move signals the visitor is engaged. That is the moment to flush the queue.
- Leave essentials alone. Anything the page needs to render or function at load stays out of the queue.
What shipped
QueueForge holds the scripts you mark as non-essential and releases them on the first interaction. The first paint is lighter, the main thread is free to answer that first tap, and the deferred work happens a moment later when it no longer competes with responsiveness. INP improves because the browser is no longer busy at the exact moment the user reaches for the page.
What I learned building it
The engineering lesson was about honesty in defaults. It is tempting to defer aggressively and show a great lab score, but if you defer something the page needs, you have traded a metric for a broken experience. The safe posture is to defer what is clearly non-essential and make it easy to keep specific scripts out of the queue.
If your WordPress site has a poor INP and a pile of third-party scripts, this is worth trying. QueueForge is free on WordPress.org. For the wider approach, see my note on fixing INP.
FAQ
Why defer scripts until interaction?
Most third-party and enhancement scripts are not needed for the first paint. If they run on load, they compete with the browser's ability to respond to the first tap or click, which is what INP measures. Releasing them on first interaction moves that work off the critical path.
Does deferring break anything?
It can if you defer a script the page needs immediately, so QueueForge targets non-essential scripts and releases the queue on the first interaction, which is usually within a second or two of the page becoming usable. Anything genuinely needed at load should stay out of the queue.
Is this the same as async or defer attributes?
Not quite. async and defer change when a script downloads and parses relative to HTML. This is about not executing heavy work until the user actually engages, which is a different lever aimed specifically at interaction responsiveness.