Senior Payments Engineer — Acquiring & Payment Processing

The salary range for this role is $5,000 - $9,500 per month (Gross in USD) About Sezzle: With a mission to financially empower the next generation, Sezzle is revolutionizing the shopping experience beyond payments, blending cutting-edge tech with seamless, interest-free installment plans that make shopping smarter and more accessible. We’re not just transforming payments; we’re redefining how people discover, interact with, and purchase the things they love while driving real impact on merchant sales through increased conversions and higher order values. As we continue to shape the future of fintech and retail, we’re building an innovative, dynamic team passionate about creating more than just a transaction but a truly unique shopping journey. If you’re excited about pushing boundaries in tech and delivering a game-changing experience for consumers and merchants alike, come join us at Sezzle and help create the future of shopping! Compensation : For this senior development role, with 7+ years of experience, the compensation range is $5,000 - $9,500 USD per month. This range acknowledges the extensive expertise, leadership capabilities, and significant contributions expected at this level, offering a competitive salary to reflect the value of advanced skills and experience. About the Role: We're hiring a Senior Payments Engineer to own and scale the systems at the heart of Sezzle's acquiring and payment-processing stack — the services that integrate with processors and gateways (Stripe, Adyen, Fiserv, Plaid, and more partners from the broader acquiring ecosystem), move funds, and keep transactions accurate, auditable, and resilient. This is a backend-focused, high-ownership role. You'll partner closely with Product, Risk, Compliance, and Support, as well as other engineering teams, to deliver scalable solutions to hard problems in authorization, settlement, reconciliation, and disputes. You'll mentor teammates, unblock peers, and occasionally lead small project teams to delivery. What You'll Do: Design and build backend services in Golang that integrate with payment processors, gateways, and card networks Own critical money-movement flows end to end: authorization, capture, settlement, refunds, reconciliation, and chargeback/dispute handling Build idempotent, fault-tolerant, auditable transaction processing within a distributed architecture (transactional outbox patterns; queues such as Kafka, SQS, or RabbitMQ) Operate within PCI DSS scope — tokenization, network tokens, secure handling of payment data, and 3DS/SCA flows where applicable Instrument and monitor payment health: authorization/decline rates, processor performance, latency, and settlement accuracy, driving continuous improvement Use AI tooling (Claude and equivalent LLMs) as part of your daily workflow to accelerate design, coding, research, testing, and documentation — within Sezzle's security and data-handling policies Mentor engineers and help raise the bar across the team Demonstrated experience working with Claude or equivalent large language model tools is required; candidates must be comfortable leveraging AI to enhance productivity, research, and communication. What We Look For: 7+ years of backend or full-stack engineering experience, with meaningful time spent on payments, fintech, or money-movement systems Strong Go (preferred), or comparable experience in Python, building and serving REST APIs Hands-on experience integrating with payment processors, gateways, or acquiring systems, and familiarity with payments fundamentals: authorization vs. settlement, tokenization, idempotency, reconciliation, and chargebacks/disputes Experience in distributed, cloud-based architectures using patterns like transactional outboxes or queuing tools (Kafka, SQS, RabbitMQ) Demonstrated, hands-on use of Claude or an equivalent LLM to enhance productivity, research, and communication — you're comfortable making AI a core part of how you work and can show how it's improved your output Bachelor's degree in Computer Science, Engineering, or a related field. Preferred Knowledge and Skills: Experience with SQL based RDMS through an ORM tool Comfortable using observability platforms like Prometheus, or vendor solutions like NewRelic or Datadog to instrument your code for production monitoring and alerting. DevOps experience with CI/CD pipelines Familiarity with containerized micro-service architecture deployed with Kubernetes on AWS Demonstrated history of delivering commercial APIs and web applications A clear record of getting products to market and prioritizing solutions and improvements based on stakeholder/customer feedback. Nice to Have Direct experience with payments acquiring ecosystem like; Adyen, Stripe, Marqeta, Fiserv, etc. Exposure to PCI DSS, 3DS/SCA, network tokenization, or payments compliance SQL-based RDBMS through an ORM Observability platforms (Prometheus, Datadog, New Relic) for production instrumentation and alerting DevOps / CI/CD pipeline experience; containerized microservices on Kubernetes / AWS A track record of shipping commercial payment APIs and prioritizing based on stakeholder/customer feedback AI at Sezzle Sezzle runs an AI-first product and engineering culture — we start projects in Claude and expect engineers to use AI to move faster and think more rigorously. In a payments environment, we do this responsibly : AI tools accelerate how we design, build, and document, but cardholder data, credentials, and secrets never leave our secured environment. We're looking for someone who treats AI fluency and secure-by-default engineering as two sides of the same skill. About You: You have relentlessly high standards - many people may think your standards are unreasonably high. You are continually raising the bar and driving those around you to deliver great results. You make sure that defects do not get sent down the line and that problems are fixed so they stay fixed. You’re not bound by convention - your success—and much of the fun—lies in developing new ways to do things You need action - speed matters in business. Many decisions and actions are reversible and do not need extensive study. We value calculated risk-taking. You earn trust - you listen attentively, speak candidly, and treat others respectfully. You have backbone; disagree, then commit - you can respectfully challenge decisions when you disagree, even when doing so is uncomfortable or exhausting. You have conviction and are tenacious. You do not compromise for the sake of social cohesion. Once a decision is determined, you commit wholly. You deliver results - you focus on the key inputs and deliver them with the right quality and in a timely fashion. Despite setbacks, you rise to the occasion and never settle. Sezzle’s Technology Stack: Languages: Golang, Typescript, Python Frontend: Typescript - React and React Native Backend: Golang Database: MySQL, Postgres, Elasticsearch DevOps & Cloud: AWS, Kubernetes Version Control: Git CI/CD: Gitlab Testing: Developer-driven, focus on automated unit, integration, and end-to-end tests Sezzle is focused on using open source, and we build what we can before buying! What Makes Working at Sezzle Awesome? At Sezzle, we are more than just brilliant engineers, passionate data enthusiasts, out-of-the-box thinkers, and determined innovators; we are skilled musicians, yogis, cyclists, chefs, golfers, dog-lovers, and rock-climbers. We believe in surrounding ourselves with not only the best and the brightest individuals, but those that are unique and purpose-driven in all that they do. Our culture is not defined by a certain set of perks designed to give the illusion of the traditional startup culture, but rather, it is the visible example living in every employee that we hire. #Li-remote #Full-time