Senior Backend Engineer in London

This is a Senior Backend Engineer position. You'll work across the engineering surface which spans payment orchestration, merchant APIs, settlement flows, internal business services, and the infrastructure that supports them.

What you work on will depend on where the team needs you most and where your strengths are best applied. Some engineers go deep on payment orchestration and partner integrations. Others focus on merchant-facing APIs and developer experience. Others build the internal services that power finance, ops, and compliance workflows. The common thread is senior-level backend ownership: you'll design APIs, build services, own your deployments, and ensure the systems you ship are correct, observable, and production-grade.

Day-to-day, you'll write technical design documents, ship production code, collaborate on architecture decisions with your engineering lead, and operate with the autonomy and accountability expected of a senior IC in a fast-moving payments team. You'll work primarily in Rust and TypeScript, with infrastructure managed through AWS and Terraform. We expect engineers to use AI tools effectively in day-to-day work — AI-assisted coding combined with strong human review is a core part of how we operate.

• Backend service design & delivery: Design, build, and maintain backend services across the platform — payment flows, APIs, data pipelines, and internal tooling.
• Make sound architectural decisions for the services you own: API design, data modelling, error handling, and system boundaries.
• Write technical design documents before major implementation work and participate in architectural reviews.
• Ownership & operations: Own your services end-to-end: implementation, testing, deployment, monitoring, and operational support.
• Contribute infrastructure using AWS and Terraform — we don't have a dedicated infra function, so engineers own their infra.
• Build observability into everything you ship: logging, metrics, tracing, and alerting that meet the reliability bar of a production payment system.
• Respond to and learn from production incidents, driving improvements to system resilience.
• Collaboration & engineering culture: Collaborate with cross-functional stakeholders including Product, Design, Ops, Finance, Legal, and BD to turn requirements into clean implementations.
• Participate in code review culture with AI-assisted development workflows, including automated agent reviews on PRs.
• Contribute to engineering standards, documentation, and team processes that help the team scale.

• Senior-level backend engineering experience — you've designed, shipped, and operated production services with real users and real consequences.
• Strong API and system design skills — you can make sound architectural decisions in ambiguous problem spaces and reason clearly about trade-offs.
• Production experience with cloud infrastructure (AWS preferred), comfortable working with managed services in a cloud-native environment.
• Comfortable owning infrastructure via Terraform or equivalent — you deploy and manage what you build.
• Ability to translate business requirements from non-engineering stakeholders into correct, maintainable implementations.
• Strong written and verbal communication — you write clear technical documents, reason about trade-offs with non-engineers, and work effectively in an async, remote team.
• Uses AI tools effectively in day-to-day engineering — AI-assisted coding combined with strong human review is a core part of how we work.

• Rust experience or strong systems-language background with willingness to ramp quickly (AI-assisted).
• Experience with payment systems or financial infrastructure — transaction lifecycles, settlement, reconciliation, fees, FX.
• Experience building merchant-facing or developer-facing APIs and tooling.
• Exposure to data transformation, reporting pipelines, or internal business systems.
• Crypto/Web3 familiarity — understanding of wallets, tokens, chains, stablecoins, or on-chain settlement patterns.

• Fully remote position with a budget for your home office or work environment.
• Regular team offsites to incredible locations around the world.
• Opportunities to travel to conferences and community events.
• Generous PTO and parental leave.
• Meaningful learning & development budget.
• Competitive compensation package including salary, equity, and potentially tokens.
• Healthcare coverage for US-based team members.
• The chance to build at the forefront of onchain payments with one of the most recognised companies in Web3.