Backend Development
Oportun
FinTech app with secure Nest.js APIs for loan management and payment processing.
Industry
FinTech
Platform
Mobile (iOS & Android)
Year
2023
/ Overview
About the project.
Oportun is a mission-driven financial services company providing affordable loans and savings products to underserved communities. As a Backend Developer, built secure Nest.js APIs handling loan management, payment processing, and user authentication — all built with strict data validation and audit logging.
Visit live siteSecure
Financial data APIs
0
Payment processing errors
Compliant
FinTech API standards
Auditable
All financial transactions
/ Challenge
The problem we had to solve.
Building secure, compliant backend APIs for financial services — loan origination, payment processing, and user authentication — where correctness and regulatory compliance are absolute requirements with no room for error.
/ Solution
How we turned it into a working product.
Developed modular RESTful APIs using Nest.js for loan management, payment processing pipelines, and JWT-based authentication — with strict input validation, idempotency handling, and audit logging throughout.
/ Technology
Stack behind the build.
The tools and platforms used to ship the product, grouped by responsibility.
Mobile
Backend
/ Team
The delivery team.
3 specialists contributed across delivery, engineering, design, infrastructure, and QA.
/ Goals
Project Goals
Build a secure, reliable API foundation for a financial services app serving underserved communities — handling sensitive financial data with the correctness, auditability, and compliance that FinTech demands.
Secure Loan Management APIs
Built Nest.js API modules for loan origination, status tracking, and repayment management with strict input validation, role-based access control, and audit logging on all financial transactions.
Payment Processing Pipeline
Developed a reliable payment processing API layer with idempotency handling and retry logic — ensuring no payment is ever double-processed or silently lost regardless of network conditions.