Senior Software Engineer, Backend (PMI Integrations)

Affirm

📍 Kitchener, Region of Waterloo, Canada

Full-time Other-General Posted February 20, 2026

Job Description

Overview

Affirm is reinventing credit to make it more honest and friendly, giving consumers the flexibility to buy now and pay later without any hidden fees or compounding interest.

The Partner Merchant Interface (PMI) team builds the APIs and solutions that power Affirm’s integrations with Enterprise Merchants and Partners. We create and manage the APIs and tools that drive checkout and merchant onboarding, and we collaborate with stakeholders to design and build custom end-to-end integrated solutions.

What You’ll Do

  • With the support of your team’s tech lead and manager, you will break down larger projects into individual tasks, deliver them in multiple phases, and collaborate with others to ensure timely delivery of your work.
  • You will support your peers and stakeholders in the product development lifecycle by collaborating with product management, design & analytics by participating in ideation, articulating technical constraints, ...