One ad is a guess. Ten ads is a test. The fastest way to find a winner is to produce many versions of the same idea, run them, and let real attention decide. Because each render in Krex AI costs 1 credit, batch testing is finally affordable for solo founders and small teams. Here is how to do it.
Change one thing at a time
A clean A/B test isolates a single variable so you know what actually moved the needle. Start from one strong ad, then spin off versions that each change just one element:
- Hook. Same ad, different opening line and first frame.
- Avatar. Swap the presenter, or compare a talking-head version against a faceless one.
- Scene. Reorder your B-roll cut-ins or change the multi-scene sequence.
- Voice. Test an energetic read against a calm one.
- End card. Try different offers or calls to action.
Step by step
- Build your base ad in the Product Ad wizard or the Marketing Copilot, and get it as strong as you can.
- Ask the Copilot to draft several hook variants, then create one version per hook.
- For two or three of those, swap the avatar or switch between talking-head and faceless to widen the test.
- Add a couple of scene reorders to see if pacing changes performance.
- Batch render the set. Aim for around ten versions so you have enough signal.
- Keep auto-captions on for every version so the only differences are the ones you intend.
Post and read the signal
Schedule the batch with Automation so the versions go out steadily instead of all at once, which keeps the comparison clean. Watch the early signals: hold rate in the first three seconds, watch-through, and the action you actually care about, clicks or conversions. The hook usually decides hold rate; the offer and end card usually decide conversion.
Double down on the winner
Once one or two versions pull ahead, stop spreading effort across the losers. Take the winning hook and build a fresh batch around it, this time varying a different element, like the avatar or the end card. This is how you compound: each round narrows in on what your audience responds to, and your next batch starts from a proven foundation instead of a guess.
Keep the loop running
Audiences fatigue, so a winner today is not a winner forever. Re-run the test every few weeks with fresh hooks, and let scheduling keep new versions flowing. The goal is a repeatable system: produce ten, find one, scale it, repeat.
A simple cadence
- Round one: ten hook variants, find the best opener.
- Round two: best hook, vary the avatar or format.
- Round three: best of both, vary the offer or end card.
Testing is no longer the expensive part. Build your base ad in the Marketing Copilot, batch your variations, and let the winner reveal itself. See how credits scale on pricing.