Role overview

As a Staff Software Engineer focused on Payment Processing at Checkout.com, you will define the technical direction for the company’s Gateway, Routing and Payout platforms. These systems process billions of transactions annually for major brands like eBay, Spotify, Klarna, Uber, and Sony. You’ll work on infrastructure where every payment and payout passes through, making decisions about correctness, availability, latency and routing quality that directly impact merchants’ approval rates and revenue.

Key responsibilities

Own the architecture of high-throughput, low-latency distributed systems, establishing service boundaries, data models and integration patterns that enable them to scale significantly.
Design for resilience from the ground up, incorporating redundancy, graceful degradation, backpressure, idempotency and recovery mechanisms to prevent partial failures from reaching customers.
Set and defend non-functional requirements including availability targets, latency percentiles, throughput ceilings, data durability and recovery objectives.
Lead complex technical decisions from problem definition and design review through to production rollout, migration and decommissioning of legacy systems.
Drive operational excellence by enhancing observability, alerting, capacity planning, load and chaos testing, and incident response practices across teams.
Raise engineering standards through design reviews, code review, pairing and mentorship, developing the senior engineers around you.
Collaborate with product, platform and other engineering teams to coordinate delivery, remove obstacles and keep multi-team initiatives aligned on shared technical direction.

Requirements

Significant production experience building and operating distributed backend systems, with a demonstrated track record of technical leadership across multiple teams.
Proven ability to design systems for high throughput and low latency, with strong intuition for identifying where systems break under load.
Deep knowledge of resilience patterns in distributed systems, including idempotency, retries and backoff, circuit breaking, queueing, backpressure and consistency models.
Strong proficiency in either .NET or Java, with the ability to write clear, maintainable production-ready code.
Hands-on experience with event-driven and streaming architectures, and working with relational and non-relational data stores at scale.
Experience with cloud-based application development using AWS and Azure, including containers, orchestration and infrastructure as code.
Ownership experience running production systems on call, with demonstrated commitment to observability, monitoring and incident response.
Track record of leading complex migrations or re-architectures of live, business-critical systems while maintaining availability and data integrity.
Excellent communication skills, ability to influence without direct authority, and capability to explain technical trade-offs to both technical and non-technical stakeholders.

What makes this role worth considering

Checkout.com operates at massive scale, processing over 10 billion transactions yearly across six continents with offices in 20 cities, headquartered in London. This role offers the opportunity to work on genuinely critical infrastructure where small improvements in performance, availability or routing directly affect the revenue of major global businesses. You’ll operate as a force multiplier, shaping architecture and raising engineering standards across multiple teams while tackling the hard trade-offs inherent in building resilient, high-scale payment systems.