HTML5 Banner Developer - Display Ad Creative

Hey - we're a digital ad team running constant campaigns across sportsbook and iGaming, and we need someone who can actually build the banners, not just design them.

If you live in HTML, CSS, and vanilla JS, get a kick out of squeezing a slick animation into a sub-150 KB file, and have shipped enough creative through Google Ad Manager to know what gets blocked before you even hit upload - keep reading.

What you'll actually do

Build a single responsive banner.html per campaign that adapts cleanly across every standard IAB size - 300×250, 300×600, 320×50, 320×100, 728×90, 970×250, mastheads - from one file. No "export at every size" workflow. Hand-coded fluid CSS, smart use of clamp() and container queries, animations in CSS keyframes or GSAP, the whole thing minified and lean.

Once the base file is dialled in, churning out copy/colour/offer variants should be quick - that's most of the day-to-day.

You'll also be the person who knows why a creative gets rejected by GAM/DV360 before it goes up, what counts toward the polite-load budget, and how to write click handling that an ad server's iframe sandbox is actually happy with.