Senior Backend Engineer

Duplo is a Lagos-based fintech startup that enables businesses in Africa to automate their spend management, simplify cross-border payments, and control business finances all on one platform.

We want to make B2B payments as simple as P2P payment apps. Most business payments in Africa are made offline….yikes. We are on a mission to transform this. We are backed by top investors including Tribe Capital, Commerce Ventures, Liquid2 Ventures, My Asia VC, Soma Capital, YCombinator, Oui Capital, and others.

This is a unique opportunity. You'll have the responsibility and resources to take a significant part in the creation of a paradigm-changing product that will impact millions.

Responsibilities:

Backend Development:

• Design, develop, and maintain scalable, reliable backend systems using TypeScript and NestJS, with a focus on correctness in financial systems
• Design robust service boundaries and maintainable architecture across distributed services
• Architect and optimize PostgreSQL schemas for scale, including transaction handling, indexing strategy, and patterns that protect data correctness
• Apply Redis effectively for caching, coordination, rate-limiting, and distributed locking

Cloud Infrastructure:

• Reason effectively about deployment safety, observability, scaling, and incident diagnosis in production environments running on Docker, Kubernetes, and AWS
• Maintain strong operational understanding of configuration and secrets handling, runtime behaviour, and rollback strategy
• Work closely with DevOps to ensure infrastructure decisions support reliability; treating infrastructure as a shared concern

Technical Leadership:

• Champion technical design and implementation for large, high-risk, or high-complexity initiatives
• Break down complex technical requirements into manageable, well-sequenced work
• Mentor and guide junior engineers, raising engineering standards through example
• Make sound, well-reasoned decisions on architectural trade-offs, migration approaches, and rollout safety, and know when to escalate decisions with broader business impact

Quality & Risk Ownership:

• Understand edge cases in money movement and design with operational safety and compliance in mind, not just functional correctness
• Drive thorough testing practices to ensure robust, reliable code before it reaches production
• Take responsibility for overall outcomes, not just tasks

Collaboration:

• Work seamlessly with cross-functional partners including product, compliance, finance, operations, support, QA, DevOps, and external providers, communicating clearly and adapting your approach to whoever you are working with
• Collaborate closely with fellow engineers through code review, pairing, and technical discussion, giving and receiving feedback in a way that raises the quality of the team's work, not just yours

Documentation and Communication:

• Create clear technical documentation for system designs, APIs, and processes
• Communicate effectively with stakeholders through technical breakdowns and status updates

Requirements:

Technical Skills:

• Minimum of 7 years of backend engineering experience, with deep expertise in TypeScript and NestJS
• Strong command of PostgreSQL, including schema design for scale, transaction handling, and indexing strategy
• Practical expertise with Redis for caching, coordination, rate-limiting, and distributed locking
• Strong operational understanding of Docker, Kubernetes, and AWS
• Experience working within Agile/Scrum methodologies

Software Engineering:

• Demonstrated experience in fintech systems, including orchestration, provider integration resilience, and compliance-sensitive design
• Deep understanding of sound architectural trade-offs and patterns that protect correctness in financial systems
• Strong commitment to writing clean, testable, maintainable code

Professional Skills:

• A track record of owning complex, high-stakes technical work from design through to production, and standing behind the outcomes
• Strong communication skills, with the ability to work effectively across engineering, product, compliance, and external partners
• A demonstrated habit of catching your own issues before they reach QA or production, and of treating failure as something to learn from rather than deflect

Experience:

• Experience mentoring or raising the technical standard of a team, not just delivering individually
• Demonstrated experience working in fintech or another high-compliance industry