3-service full-stack credit platform for farmers with no credit history.
- Role
- Full-stack developer
- Type
- Fintech · Full-stack
- Year
- 2026
- Links
- GitHub ↗
Problem
Most rural farmers have no credit history, so banks have no way to judge whether they can repay a loan.
Solution
A platform made of a mobile app, a core API and a scoring service. Farmers register, sign contracts and see their credit score with an explanation. Keypad phones get a USSD flow.
What I did
- Built a 20-endpoint REST API on Express and PostgreSQL (Supabase, PostGIS): registration, farmers, contracts, scoring and document upload.
- Wrote the OTP flow for phone verification: codes expire, and repeated wrong attempts lock the number for a while.
- Built two-sided contract signing: the buyer confirms with an OTP, the farmer signs with an OTP in the app or with a PIN in the USSD menu on a keypad phone.
- Uploading the ÇKS land document fills in the registration form: the API passes the file to the scoring service, which reads the land size and other details from it.
- Wrote a React Native app with separate screens for farmers and buyers: credit score, the effect of each factor, an explanation of the credit limit and a score history chart.
- Connected the API to the FastAPI scoring service: when the service is down the API returns a clear 502, and database errors are mapped to the right HTTP codes in one central middleware.
How it's built
Mobile appReact Native, farmer and buyer
USSDKeypad phones
Express API20 endpoints, OTP
Scoring serviceFastAPI, score and ÇKS reading
PostgreSQLSupabase, PostGIS
The farmer uploads the ÇKS document and the scoring service reads it to fill in the form. After the OTP check the farmer is saved.
Stack
- Node.js
- Express
- PostgreSQL
- Supabase
- React Native
- Expo
- FastAPI
- REST API
Screens
