Backend Software Engineer, CoreApp

OnePay

23h • Remote

About The Position

OnePay is the consumer fintech trusted by millions of Americans to make money better.
Our financial system is broken. High fees, low rates, and too few ways to actually grow your money. We’re fixing it. And we’re moving fast.
We’re an all-in-one financial services platform that brings together banking, high-yield savings, credit cards, point-of-sale lending, investing, and crypto in one place. We also partner with employers, HCM providers, gig platforms, and others to deliver embedded financial services to millions of employees and frontline workers.
We’re backed by Walmart, the world’s largest retailer, and Ribbit Capital, one of fintech’s most respected investors, giving us rare scale, distribution, and the opportunity to build something truly category-defining.
But what really sets OnePay apart is how we move. Our customers don’t have time to wait… and neither do we. This place moves fast, and we’re looking for people who are:
Ready to run
Hungry and driven by urgency
Exceptional at what they do, with low ego
Comfortable operating in motion
As a Backend Software Engineer on the Core App team at OnePay, you will build backend systems that directly power our mobile and web user experience. You will:

Requirements

• 5+ years of professional experience building and scaling backend systems in consumer technology or fintech environments
• Experience designing and operating distributed systems, APIs, and data flows that support user facing applications
• Familiarity with message brokers and event driven systems, as well as caching and performance optimization strategies
• Demonstrated ability to lead technical execution, mentor other engineers, and deliver with a high bar for quality
• Drive and proactivity – everyone here is a builder and executor.

Responsibilities

• Design, build, and ship backend services that support user-facing features across mobile and web experiences
• Collaborate closely with frontend engineers, product managers, designers, and data partners
• Lead backend technical planning and contribute to architecture decisions that improve scalability, reliability, and performance
• Proactively identify opportunities to improve user experience through backend optimizations and system enhancements
• Build and maintain clear technical documentation to support a growing and distributed engineering organization

Benefits

• Competitive base salary, stock options, and health benefits from Day 1
• 401(k) plan with company match
• Remote-friendly (US), flexible time off (FTO), and opportunities for growth
• A high-growth, mission-driven, inclusive culture where your work has real impact

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed