By shifting the popup format from a traditional lightbox to a fullscreen takeover, we hypothesized that the additional visual focus and removal of background distractions would heighten user attention and lead to higher opt-in conversion rates for both email and SMS.

An A/B test was conducted to compare two display styles for popups:

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Randomized site visitors were exposed to either the lightbox or fullscreen version. Key metrics observed:

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• Email Conversion Rate – Percentage of visitors who submitted their email.
• SMS Conversion Rate – Percentage of visitors who submitted their phone number.

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Conversion rates were measured as the number of opt-ins divided by total popup impressions.

The test ran across five brands. Visitors were randomly assigned to either the control or variant, and opt-in behavior was tracked.

The fullscreen popup variant outperformed the lightbox control across all brands and channels. Lift ranged from moderate to significant, with particularly strong gains in both email and SMS opt-ins for some brands.

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Fullscreen popups consistently drew higher engagement and conversions across the board, suggesting that eliminating background distractions and maximizing the visual footprint of the offer increases its perceived importance.This test supports the notion that fullscreen presentation offers a meaningful UX upgrade in high-intent moments. It’s a strong candidate for default display moving forward, especially for brands looking to squeeze every bit of performance out of their popup flows.