Senior Software Engineer, Backend (Authentication Experience)

Affirm; London; On-site; CAD 153,000 - 213,000; Full time

Benefits offered by this job

Health coverage

Equity rewards

Remote-first with flexibility

Tech and wellness stipends

Job summary

Affirm is seeking an experienced backend engineer to design, develop and launch scalable backend systems in Python or Kotlin. The role emphasizes ownership, high availability, and low latency across web and mobile surfaces.

You’ll work closely with product, design, and analytics to balance constraints while driving quality and reliability. The position is remote within Canada, offering equity, monthly stipends for health and tech, and a comprehensive benefits package as part of total

Qualifications

• 4+ years of experience designing, developing and launching backend systems at scale using languages like Python or Kotlin.

Responsibilities

• Own and deliver quarterly goals for your team and lead engineers through ambiguity.
• Collaborate with product, design & analytics to articulate constraints and trade-offs.
• Identify and solve project, process, technology or business issues.
• Support operations and availability of team artifacts with metrics and on-call efforts.
• Mentor peers and foster a culture of quality and ownership through code reviews and design standards.
• Develop talent by giving feedback and guidance and leading by example.

Skills

Backend design

Python/Kotlin

Distributed systems

AWS

Kubernetes

MySQL

Frontend awareness

Code quality

Ownership

Tools

Kubernetes

MySQL

AWS

Job description

At Affir, we exist for the moments that matter—giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most.

Auth Experience owns the customer journeys during authentication, verification, and fraud journeys. You'll work to build the backend orchestration layers that drive our Web and Mobile surfaces. In this role, you will need to gain a deep understanding of the business, product and engineering context, and utilize that context to own and deliver high-availability and low-latency systems that affir customers use every day.

What You’ll Do

• You will be responsible for owning and delivering quarterly goals for your team, leading engineers on your team through ambiguity to solve open-ended problems, and ensuring that everyone is supported throughout delivery.
• 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, and partnering on decisions that properly consider risks and trade-offs.
• You will proactively identify project, process, technology or business issues, advocate for them, and lead in solving them.
• You will support the operations and availability of your team’s artifacts by creating and monitoring metrics, escalating when needed, and supporting “keep the lights on” & on-call efforts.
• You will foster a culture of quality and ownership on your team by setting or improving code review and design standards for your team, and advocating for them beyond your team through your writing and tech talks.
• You will help develop talent on your team by providing feedback and guidance, and leading by example.

What We Look For

• You have 4+ years of experience designing, developing and launching backend systems at scale using languages like Python or Kotlin.
• You have a track record of developing highly available distributed systems using technologies like AWS, MySQL and Kubernetes.
• You have experience working close to the web and mobile layers, with an understanding of frontend design patterns such as fraud prevention and backend-for-frontend.
• You have experience defining a technical plan for the delivery of a significant feature or system component with an elegant, simple and extensible design. You write high quality code that is easily understood and used by others.
• You are proficient at making significant changes in a large code base, and have developed a suite of tools and practices that enable you and your team to do so safely.
• Your experience demonstrates that you take ownership of your growth, proactively seeking feedback from your team, your manager, and your stakeholders.
• You have strong verbal and written communication skills that support effective collaboration with our global engineering team.

Pay Grade - N

Equity Grade - 6

Employees new to affirm typically come in at the start of the pay range. affirm focuses on providing a simple and transparent pay structure which is based on a variety of factors, including location, experience and job-related skills.

Base pay is part of a total compensation package that may include monthly stipends for health, wellness and tech spending, and benefits (including 100% subsidized medical coverage, dental and vision for you and your dependents). In addition, the employees may be eligible for equity rewards offered by affirm holdings, inc. (parent company).

CAN base pay range per year: CAD $153,000 - $213,000.

Location - Remote Canada

This remote role is open only to candidates residing in Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, or Saskatchewan.

This posting is for an existing vacancy.

Remote

Remote-first with flexibility built in

Affir is proud to be a remote-first company. Most roles can be done from almost anywhere within the country of employment. Some positions may occasionally require in-person work at an affir office, and a few are office-based due to the nature of the work. All new hires will be invited to attend an in-person onboarding experience.

Benefits Designed For You

Our benefits reflect our commitment to care, transparency, and flexibility. Here are a few highlights:

• Health coverage at no cost: We cover 100% of premiums for employees and their dependents.
• Spending stipends: Monthly stipends support your tech setup, and the ability to choose health and wellness options that are right for you.
• Time off to recharge: Flexible time off and generous holiday calendars help you rest when you need to.
• Own a piece of what you build: Our employee stock purchase plan (ESPP) lets you buy affirm stock at a discount.

We’re committed to providing an inclusive interview process, including accommodations for candidates with disabilities. If you need support, we’re happy to help.

For positions based in San Francisco or Los Angeles: affirm considers qualified applicants with arrest and conviction records, as required by law.