🧰 Kernvel Free Tools · Free forever

Seasonal effects that don't slow your store down.

Snow in December, leaves in autumn, confetti for a launch. One lightweight canvas overlay, scheduled in advance, with zero layout shift by construction.

30
Effects
12
Seasonal presets
0
Layout shift (CLS)
$0
Free forever

Most effect apps are a performance problem in a party hat

This one is built the other way round. The speed work is the product.

Zero layout shift

Everything renders in one fixed, non-interactive <canvas> above your theme. It cannot push your content around, so it cannot cost you CLS.

Never delays your paint

The engine initialises during browser idle time and makes no per-visit server call — your settings are embedded in the page. Nothing blocks your largest contentful paint.

Knows when to back off

Hard particle cap, automatic downscaling on mobile and low-end devices, and a full stop when the tab is hidden. It also respects the visitor's reduce-motion setting.

Set it once, forget it

The scheduler is the part competitors charge for.

Schedule the season

Give it a start and end date. It switches itself on for Christmas and off again on the 2nd, without you remembering.

Choose where it runs

Per-template targeting — home only, product pages, or the entire store with one toggle. Mobile is a separate switch.

Twelve one-tap presets

Christmas, winter, Halloween, Valentine's, autumn, sale, New Year, spring, birthday, St Patrick's, summer night and Black Friday.

Or tune it yourself

Density, speed, size, drift, colour and palette — plus 8 decorative overlays and the option to drop in your own image as the falling particle.

What it can't see

Worth being explicit about, because most apps aren't.

No product, order or customer data

The app requests two scopes: theme access, to detect whether the app embed is switched on, and app proxy, to serve your own configuration back to your storefront. That's the whole surface.

No shopper tracking

No profiles, no cookies for advertising, no AI. The only thing recorded is an aggregate count of how often the effect rendered.

Free, with no asterisk

No paid tier, no plan limits, no usage cap. If you want a hand setting it up, that's free too — book 15 minutes.