How Paytm and Google Pay Made QR Scanning Feel Instant

The Bar: “Point → Pay” With Zero Friction

1) They Stream Preview Frames (Not Photos)

2) Do Less Work Per Frame (Downscale + ROI)

Perceived Speed: Win the First 300ms

3) Detect Fast, Decode Only When Confident

Under the Hood: Android vs iOS

4) Local Parsing (So the “Scan” Doesn’t Need the Network)

5) Performance Engineering: Threads + Backpressure

6) Camera Tuning Beats Clever Algorithms

7) Reliability in the Real World

9) Trust and Safety: Fast, But Not Reckless

10) UX: Make the Next Step Automatic

Why This Was Such a Good Idea