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Case studyFintech

Everyday payments, made to feel effortless.

A mobile-first product experience for the small, frequent moments where trust and clarity matter most.

A quiet Tokyo backstreet at night, a paper lantern glowing beside a parked bicycle
Client
PayPay, with Robosoft
Industry
Fintech and payments
Region
Japan
What we did
Mobile app engineering, product design

About the client

PayPay is Japan’s most widely used cashless payment app. People use it to pay at shops and restaurants by scanning a QR code, to send money to friends, and to pay bills, and it has grown into a wider platform for everyday finance.

By July 2025 PayPay reported more than 70 million registered accounts. Robosoft Technologies is listed by PayPay as a partner for app development, and our work on the app was done alongside Robosoft.

Source: PayPay, July 2025

Overview

A payment happens in a few seconds, often standing at a counter with one hand free and a queue behind you. The app has to feel instant, and it has to leave people certain about what they just approved. Our work focused on the mobile experience around those moments.

Business requirement

Make the core payment flows fast enough for a busy till and clear enough to trust: an action that is impossible to miss, the amount and the recipient always visible before confirming, and a record that is easy to find afterwards. Everything had to hold up for tens of millions of people with very different levels of comfort with technology.

Solution

We worked on the scan-and-pay journey as a single, uninterrupted motion: open, scan, check the amount and the shop, confirm. The primary action sits where a thumb rests, and the confirmation screen shows exactly what is being paid, to whom, before anything is sent.

Balances and recent transactions stay close to the main screen, so people can check what happened without hunting through menus. A shared set of components kept these patterns consistent as new features were added around the payment core.

HighlightsWhat the product gets right

What the experience is built around

  • Scan, confirm, pay

    The everyday payment reduced to one clear motion, with the shop and the amount confirmed before money moves.

  • One-handed by design

    Primary actions placed within reach of a thumb, for paying while holding a bag, a coffee, or a child’s hand.

  • History you can trust

    Recent payments and balances visible at a glance, so a quick check after paying never turns into a search.

  • Consistent as it grows

    A shared component set so new services added around payments still look and behave like the same app.

ChallengesWhat made it hard

Challenges we worked through

  1. 01

    Speed at the counter

    Every extra tap is felt in a queue. Flows were trimmed to the fewest steps that still keep the person in control.

  2. 02

    Confidence before confirming

    The amount and the recipient had to be unmistakable on small screens and in bright light, without slowing anyone down.

  3. 03

    Everyone, not just early adopters

    A payment app in Japan is used by students and grandparents alike. Clear language and generous touch targets mattered as much as speed.

  4. 04

    Scale and reliability

    At this volume, edge cases are everyday cases. States for slow networks, failed payments, and retries were designed as carefully as the happy path.

ApproachHow the work ran

Our approach

We worked within the client’s product process alongside Robosoft, with design and engineering together on each journey rather than handing screens from one team to the next.

  1. Step 1

    Map the moment

    Follow a payment from opening the app to checking the receipt, and note every point of hesitation.

  2. Step 2

    Shape the flow

    Prototype the shortest clear path and test it against real situations: one hand, poor signal, a long queue.

  3. Step 3

    Build the components

    Turn the agreed patterns into reusable components so every screen behaves the same way.

  4. Step 4

    Ship and refine

    Release in steps, watch how people actually use the flow, and tighten it.

Where it landed

A familiar, low-friction way to pay that keeps pace with real-world counters, and gives people the detail they need once the payment is done.

A set of patterns and components the product team can keep building on as new services arrive around the payment core.

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