Senior Software Engineer (FinTech)

About Differential Differential is growing! Yep, it turns out customers like us :) Our team of designers, developers, jokesters, and all around good folk needs more firepower. We’re proudly headquartered in Cincinnati, OH, but our team spans across the country. In addition to only choosing the best group of people to work around, we are also very picky about the types of customers we’ll work with. In line with our mission to make technology that moves people towards one another, we partner with forward-thinking pioneers and innovators to revolutionize their organizations from the inside out and bring great digital products to life, with a focus on the platform that connects people with their local church everyday. Throughout our history we’ve built a diverse range of products like transforming retail with Adidas, helping Lexmark innovate cross-industry, streamlining the sales process with Big Ass Fans, to multi-platform mobile apps for large audiences with Crossroads Church. Our Company’s focus is now on building the Apollos platform that connects people with their local church everyday. We hire great, trustworthy people so that we can optimize for a free & flexible culture: flexible vacation, remote work, and working on meaningful stuff you’re excited about. Job Description: We’re looking for a Lead Engineer (FinTech) to join our engineering team as a highly hands‑on individual contributor. This is not a people‑management role — you’ll be one of the senior technical engineers on the team, owning complex engineering problems and helping shape the architecture and technical direction of our FinTech products. You’ll work deeply across payments, financial integrations, APIs, data, and distributed systems while partnering closely with Product and Engineering leadership to build reliable, secure, scalable software. Many large organizations and millions of dollars rely on applying sound engineering principles to our products' rapid development. This role is for you if: You’re someone who loves hardcore software engineering. You have developed the technical judgment and validation techniques to tackle problems that don’t have obvious answers. You can take an ambiguous problem, understand the business and technical constraints, design a solution, and then build it yourself. You care about building things correctly, but you also understand that “perfect" is the enemy of “shipped”. You’re comfortable in a fast-moving environment where you’ll have significant ownership and a real opportunity to shape the product and technology. You lead through technical expertise, ownership, judgment, and influence. Above all, we are focused on finding someone that we love to work with. Culture to us isn’t a ping pong table in the breakroom or some words we put up on the wall. It’s embedded in our DNA and starts with our hiring process. We want to consider passionate people for this position. Our mission statement, core values, benefits, and more can be found at handbook.differential.com. What you can expect to do: Own the technical design and implementation of complex FinTech and payment‑related systems. Make architectural decisions and help establish engineering standards and patterns. Build and maintain APIs, integrations, services, and data systems. Work hands‑on in the codebase — designing, coding, reviewing, debugging, and shipping. Solve challenging problems involving payments, financial data, transactions, reconciliation, and third‑party integrations. Partner closely with Product and Engineering leadership to translate business requirements into strong technical solutions. Identify technical risks and proactively improve system reliability, scalability, security, and performance. Mentor and influence other engineers through code reviews, technical guidance, and strong engineering practices. Help the team move quickly without sacrificing quality or long‑term maintainability. Passion for the whole product process: we know you will have your specific areas of focus, but we find that people who are passionate about the bigger picture collaborate best on our cross‑functional teams. Demonstrated ability to rely on an iterative process to maintain momentum on projects: our work is never going to be perfect, and we expect you to be able to prioritize what matters most in order to consistently and efficiently iterate and continuously deliver valuable working software. Know how to leverage AI tools to massively accelerate deliverables while observing and enforcing sound engineering principles. What we’re after: 7+ years of professional software engineering experience. Strong experience building and scaling production payments software. Deep understanding of backend architecture, APIs, databases, and distributed systems. Experience working in FinTech, payments, banking, financial services, or other transaction‑heavy systems. Strong understanding of payment flows, transaction processing, webhooks, reconciliation, or financial integrations. Experience integrating with third‑party APIs and services such as payment processors, banks, or financial platforms. Strong experience with TypeScript/Node.js, GraphQL, PostgreSQL, and modern cloud infrastructure. Comfortable working across the stack when needed, including React/React Native. Strong architectural instincts and ability to make pragmatic technical tradeoffs. Excellent debugging and problem‑solving skills. Comfortable operating with a high degree of ownership and autonomy. Responsibilities of this position include: Gaining an understanding of who the users are, what their problems are, and why those problems exist. Putting the user — and their problems/needs — first in order to create and drive empathy for the solution you’re building. Understand, document, keep updated detailed payments system architecture. Understand and identify edge‑cases that need explicit handling in payment systems. Maintain Payment system regression detection system and uptime detection system. Translating a well‑designed solution of sketches, wireframes, or high‑fidelity mockups into fully functioning immersive experiences. Delivering approachable, modern code for web and mobile applications. Working closely with a team of product and engineering roles. Maintaining development workflow with the team’s tooling. Effectively communicating via Basecamp, Slack, and video calls. Executing with quality and speed in a fast‑paced, sometimes ambiguous environment. Incorporating feedback into your work. Delivering tested, maintainable, and documented software using modern AI‑powered techniques and approaches. Differential employees are those who: Communicate effectively with clients and teammates. Are self‑motivated. Learn quickly and relentlessly. Are curious about technology and the impact it can make on the world. Enjoy taking ownership and responsibility for their work. Enjoy collaborating with others on solving meaningful problems. Candidates must be based in the United States and be available during standard business hours for both internal and external meetings. Specific times vary based on timezone considerations for the meeting participants. There is flexibility in working hours, but there is an expectation to be able to regularly attend client and team meetings. Differential is an equal opportunity employer. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. As part of our commitment to maintaining a legal and compliant workforce, we participate in the E‑Verify program. For more information about E‑Verify, please visit the U.S. Department of Homeland Security website at #J-18808-Ljbffr Differential Dev Shop, LLC