Description
Senior Backend Engineer

About the Role

We're looking for a Senior Backend Engineer to own and build payment systems in Chexy Engine, our core backend repository. You'll work on the systems that move money-payment inflows, outflows, ledgering, settlement, and direct integrations with card networks and banking systems.

This role is about building clean, scalable, production-grade financial infrastructure. Every line of code you write will process real money for real people, which means your work needs to be precise, well-tested, and built for scale. You'll design and implement the payment systems that can handle billions in annual transaction volume.

What You'll Be Doing

• Build and maintain payment processing systems handling inflows, outflows, and multi-rail settlement in Chexy Engine
• Design and implement ledger systems using double-entry bookkeeping principles to ensure financial accuracy and auditability
• Develop and optimize direct integrations with payment networks (Visa Direct, American Express) and banking systems (e-Transfer, PAD, Bill Pay, etc.)
• Write clean, well-tested, production-grade code in NestJS and TypeScript following scalable architecture patterns
• Design event-driven systems using Google Cloud Pub/Sub for reliable, asynchronous payment processing
• Build APIs consumed by our web and mobile applications, ensuring performance and reliability at scale
• Optimize database queries and schema design in PostgreSQL (Cloud SQL) using Prisma ORM
• Implement caching strategies with Redis to handle high transaction volumes efficiently
• Write comprehensive tests and participate in code reviews to maintain code quality standards
• Collaborate with frontend, mobile, and infrastructure teams to ship features end-to-end
• Participate in on-call rotations for production payment systems

Who We're Looking For

• 5+ years of backend engineering experience, with at least 2+ years building production financial systems, payment processing, or high-volume transaction systems
• Strong experience with NestJS, Node.js, and TypeScript in production environments
• Deep understanding of relational databases (PostgreSQL preferred) including schema design, query optimization, and transactions
• Experience with ORMs (Prisma experience is a plus)
• Proven track record building and maintaining high-volume APIs and microservices
• Understanding of event-driven architecture and message queues (Google Cloud Pub/Sub, Kafka, RabbitMQ, or similar)
• Experience with financial systems concepts: ledgers, double-entry bookkeeping, reconciliation, idempotency, transaction integrity
• Strong grasp of Redis or similar caching technologies for performance optimization
• Experience with payment processing, banking integrations, or fintech products
• Ability to write clean, maintainable, well-tested code with strong attention to detail
• Strong communication skills and ability to collaborate across teams
• Self-directed with ownership mentality-you take pride in shipping reliable, production-grade systems

Bonus Points

• Direct experience with payment network integrations (Visa, Mastercard, Amex) or banking APIs
• Experience with Google Cloud Platform (Cloud Run, Cloud SQL, Pub/Sub)
• Familiarity with Terraform or infrastructure-as-code practices
• Experience building ledger systems or working with accounting principles
• Knowledge of Canadian payment systems (e-Transfer, PAD, Bill Pay)
• Experience with API documentation (Swagger/OpenAPI)
• Contributions to open-source projects in payments, fintech, or backend infrastructure
• Background in regulated industries or compliance-heavy environments

Why Join Chexy?

Build payments infrastructure that matters: Your code moves billions of dollars and powers life-changing financial transactions for thousands of Canadians

Join a tight-knit team: Work directly with founders and senior engineers who trust you to make critical decisions

Early equity: Access equity in a high-growth fintech company that's just getting started

Own real impact: No bureaucracy, no endless meetings-just smart people solving hard problems together

Toronto office: Work in-office 5 days a week with the team in Toronto

How We Hire

We keep our hiring process clear and human. You'll go through a mix of conversational interviews and technical deep-dives designed to showcase your strengths. We care about how you think, how you've solved real backend and payment problems, and how you collaborate-not just trivia questions. And we make sure there's space for your questions too.