How Popflex Re-Proved Nostra's Value

Popflex is a women’s apparel brand founded by entrepreneur and designer Cassey Ho. They are a DTC-native brand known for its feminine aesthetic, patented innovations, and community-driven design process. They want to ensure every visitor that comes to their site --- whether through viral social content or paid channels, does not have barriers (like site speed) to convert

Popflex had already been on Nostra long enough to be approaching a renewal, and the team wanted to make sure the math still held before signing on for another year.

This is the part most vendors quietly hope customers don't do. Most brands renew based on the relationship, the gut feel, or the most recent monthly report. Popflex wanted to look at the data. A new live a/b test, run against production traffic, measured the same way the original deployment had been measured. 

Popflex ran Nostra against a 50/50 A/B test for multiple days, Half of the traffic was served the unaccelerated original experience. The other half was served the Nostra-accelerated version. Same site, same products, same campaigns, same promotions. The only variable was speed.

The first place that speed showed up was the network layer. Nostra cut Time to First Byte from 817ms on the control to 606ms on the Nostra side. A 25.8% improvement, sustained over the entire test window. That isn't a synthetic benchmark or a Lighthouse score. It's TTFB measured on real production traffic, against a live control arm running the same site without Nostra in the path.

Over the course of the test, nearly a million visitors split across both arms, a sample size large enough to settle the math beyond any reasonable doubt about noise or seasonality. The CVR variance returned a Z-score of +5.73, well above the +1.96 threshold for statistical significance. The result wasn't sensitive to short-term traffic patterns, paid campaign launches, or single-day anomalies. It was consistent across the entire test period.

The numbers came back clean. Nostra's accelerated experience drove a 7.49% lift in conversion rate over the holdout. Only the speed was different. Real shoppers were converting at a higher rate, period. 

The retest framing matters. This isn't a launch case study where a vendor is showing off their best day. It's a brand that already had Nostra deployed, already had the relationship in place, and chose to make Nostra prove itself again before signing for another year. The numbers held. The conversion rate held. The renewal made sense.