About the Role
We're looking for a
Senior Backend Engineer to own and build payment systems in
our 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 our 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