Built from real WooCommerce problems

InstantStack was founded by Tom van den Hengel, WordPress and WooCommerce developer and owner of WebKenner. InstantFilter did not start as a theoretical product idea — it came from recurring performance problems in client stores.

• Developed from production experience
• Focused on WooCommerce performance
• Built and maintained in the Netherlands
• Transparent technical approach

The problem behind InstantFilter

Traditional WooCommerce filters run a heavy server process on every interaction. They send an AJAX request, boot WordPress fully, run complex database queries, process product results on the server and then send new HTML back to the browser.

For stores with many products, attributes and variations this inevitably causes:

• Noticeable wait time for shoppers
• High server load (PHP worker exhaustion)
• Poor scalability during traffic spikes
• Complex cache exclusions
• An inconsistent, slow filter experience

“On larger WooCommerce stores I kept hitting the same wall: filters felt slow even when the rest of the shop was perfectly optimized. The cause was rarely hosting or caching — it was the architecture of the filter system itself.”

Why InstantFilter was built

That frustration led to a simple question: what happens if the browser does the filter work, instead of WordPress on every click?

The result is InstantFilter’s client-side architecture:

• Product data is indexed on the server in advance.
• Filter data is packed into a JSON codebook.
• Filtering runs fully client-side in the shopper’s browser.
• No AJAX round-trips or database queries per filter action.
• Filter calculations typically finish in milliseconds in a suitable configuration.
• The initial data is fully cacheable by systems such as WP Rocket or Redis.

The developer behind InstantStack

Tom van den Hengel is a WordPress and WooCommerce developer and founder of WebKenner and InstantStack. He builds custom solutions for online stores, with a strong focus on performance, scalability and user experience.

InstantFilter grew out of recurring problems in client projects. Existing filter plugins often leaned on heavy server requests, complex queries and long wait times. From that production work he built a client-side architecture where filter actions do not constantly load WordPress and the database.

Tom works daily with WordPress, WooCommerce, PHP and JavaScript on product feeds, API integrations, large catalogs, custom filters and store performance.

Production experience as the foundation

The technical choices behind InstantFilter were shaped by projects with large catalogs, variable products and complex attribute structures. The focus is not only speed, but also maintainability, scalability and predictable behaviour for developers.

The architecture is designed to handle challenges such as:

• Stores with thousands of products and tens of thousands of variations.
• Complex product feeds and automatic stock sync.
• Performance bottlenecks from slow WP_Query and AJAX calls.
• Compatibility with existing page cache and object cache.

Our development principles

Not a black box

InstantFilter is not marketed as “fast” and left there. Our documentation explains exactly how indexing, the data layer, caching and client-side filtering work. Developers can judge for themselves whether the architecture fits their store.

Inspect our approach

We believe in being open about the technology. Use the links below to look under the hood.

• Technical documentation
• Performance explainer and benchmarks
• Changelog and updates

InstantStack as a company

InstantStack builds specialized performance tools for WordPress and WooCommerce. The focus is on solutions that fix technical bottlenecks structurally, instead of only masking them with extra caching or more server capacity.

InstantStack is the product organization behind InstantFilter, grown out of the WebKenner development studio. Development, maintenance and support are handled in the Netherlands.

Trust and transparency

We value clear communication and being reachable. Here is the key company and legal information in one place.