Downey.

Product Design Lead · Payments, Commerce & AI

I turn complex payment ecosystems into products people can understand, use, and trust.

I'm Downey Tang, a Product Design Lead at PayPay. I lead end-to-end design across consumer, merchant, and operations experiences — from 0→1 products and platform redesigns to AI-assisted product exploration and prototyping.

8+ years in product design Design Lead · PayPay O2O Designing within a 75M+ user platform Consumer · Merchant · Operations Tokyo · EN / JA / ZH

Selected Work

5 case studies · PayPay

Hands hold a phone showing the redesigned PayPay Coupons discovery experience.

PayPay · Coupon · Consumer Experience

Coupon Redesign: Shifting from Claims to Redemption to Support GMV Growth

+3.9%: Coupon redemptions
+5.3%: Coupon GMV
+38%: Search-driven claims

Read case study

Four PayPay Coupon navigation concepts compare the original discovery layout with top, bottom, and hybrid navigation options.

PayPay · Coupon · Product Strategy

Coupon Navigation: Using A/B Testing to Guide Future Coupon Growth

+106%: SKU entry usage
+90%: Online entry usage

Read case study

Private case study Project visuals are available with an access code.

PayPay · Gift Voucher · Consumer Experience

Bridging the gap: more value for users, direct reach for manufacturers

0→1 Product
End to end solution
Usability Testing

Enter access code Request access

Private case study Project visuals are available with an access code.

PayPay × ChatGPT · Agentic AI

Designing PayPay’s first ChatGPT experience—from user intent to coupon redemption

0→1 Product
Agentic AI
Direct claim flow

Enter access code Request access

Private case study Project visuals are available with an access code.

PayPay · Gift Voucher · Back Office

From a manual process across teams to one guided Back Office workflow

Workflow redesign
AI prototyping
Image guidelines

Enter access code Request access

Earlier Work

Yahoo! JAPAN · 2018–2022

Carnavi's first paid feature — 77.2% trial→paid conversion

Monetization · patent filed as main designer · 17 media reports

Olympic Route Avoidance — 9.6% of DAU during the Games

National-scale launch on an immovable deadline · division Super-Star Prize

Bicycle Navigation from zero — planning through design

0→1 · four interaction patterns prototyped · unified nav UI across 3 teams

About

Full story →

I'm a product designer with 8+ years of experience, based in Tokyo. My career has grown from designing navigation products at Yahoo! JAPAN to leading O2O product design at PayPay.

Today I work across consumer experiences, business systems, internal operations, and AI-assisted product exploration — connecting user needs, business outcomes, and implementation reality.

Currently: Design Lead, PayPay
Previously: Yahoo! JAPAN (2018–2022)
Education: M.Des, Tokyo Metropolitan Univ.
Languages: English · 日本語 · 中文
Location: Tokyo, Japan