Kasi Pay
A payments app for township merchants, designed for low-end devices and expensive data.
- Client
- Kasi Pay
- Industry
- Fintech
- Discipline
- Mobile
- Duration
- 5 months, 2025
The problem
KasiPay'smerchantsrantheirbusinessesonentry-levelAndroiddeviceswithprepaiddata.Thefirstversionoftheappwas74MB,assumedastableconnection,andlostatransactionwheneverthenetworkdroppedmid-payment.
Merchant trust is everything in cash-adjacent businesses. Every ambiguous transaction cost the company a customer and a reputation it could not easily rebuild.
What we did
We rebuilt the client around a local transaction ledger. Payments are recorded on device, queued, and reconciled with the gateway using idempotency keys, so a merchant always sees the true state even after a mid-payment failure.
The bundle came down to 11MB, the cold start under two seconds on a 2GB device, and the interface was redesigned around one-handed use in bright sunlight with high-contrast type and generous targets.
Field research in Soweto and Alexandra shaped the onboarding flow: seven steps became three, with document capture that tolerates a cracked camera lens.
Services applied
Technology
- React Native
- Expo
- TypeScript
- Paystack
- Supabase
- PostgreSQL
- Sentry
- Google Cloud
Gallery
Inside the build.
Results
What changed, measured after launch.
- App download size
- 0MB → 11MBApp download size
- Cold start on entry-level Android
- 1.8sCold start on entry-level Android
- Merchant activation completion
- +0%Merchant activation completion
- Unreconciled transactions
- 0.02%Unreconciled transactions
“They went and stood in our merchants' shops. The redesign came back with things we had never thought to ask about.”
Sibusiso DlaminiFounder, Kasi PayRelated work
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Similar problem?
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