Senior Full-Stack Engineer

On behalf of our client, a payment-provider orchestration company, we are looking for a Senior Full-Stack Engineer to join their growing engineering team.

About Our Client

Our client is building a payment-provider orchestration platform that helps businesses integrate, manage, and switch between payment services without rebuilding their systems each time.

They value thoughtful engineering, simple solutions, open communication, and products that work reliably. Their engineers contribute across the whole product lifecycle: shaping requirements, weighing technical trade-offs, building, testing, and deploying.

If you want to work across the full stack, take real ownership, and help shape a growing fintech product, we would like to hear from you.

The Role

You will design, build, and run the core systems behind the platform, from payment routing and payment-state handling to reconciliation. You will own assigned system areas end to end, lead technical decisions within them, and help shape the team's engineering practices as it grows.

This is a hands-on role, working mainly in TypeScript, React, Next.js, Node.js, and PostgreSQL alongside product, design, and other engineers.

Their Stack

TypeScript · React · Next.js · Tailwind CSS · Node.js · Express · PostgreSQL · Drizzle ORM · Zod · AWS · Git

AI tooling: Claude Code CLI · Codex CLI · AI-assisted code review

How They Work with AI

Engineers use agentic coding tools such as Claude Code CLI and Codex CLI every day, and the team builds AI-driven features into the product itself. At this level, you should know where these tools add real leverage and where they add risk, review AI-generated code rigorously, and help the team use approved tools with the right data handling, verification, and human approval.

What You Will Do

• Turn unclear requirements into practical designs, explain trade-offs, and deliver complex features end to end

• Build polished, accessible interfaces, REST APIs, and well-modelled PostgreSQL data layers

• Design and verify payment-state handling, covering idempotency, duplicates, retries, timeouts, asynchronous events, partial failures, and reconciliation

• Document significant technical decisions in your areas

• Review complex or high-risk changes for correctness, security, and maintainability, including AI-generated code

• Define testing for complex changes, including failure and recovery scenarios, and coordinate load tests

• Coordinate releases with safe migrations, configuration changes, and recovery plans

• Improve monitoring, alerting, runbooks, and service-health targets

• Join the on-call rota and handle complex investigations and escalations

• Drive security fixes and dependency upgrades, and maintain evidence for PCI DSS processes

• Mentor developers and support onboarding

What You Will Bring

• Typically 5+ years of professional software development experience, including building and operating production systems as a senior engineer

• Strong TypeScript, React, and Node.js skills, and a track record of delivering complex features across frontend, backend, and data layers

• Experience designing distributed or event-driven systems, including idempotency, retries, timeouts, and failure handling

• Experience with PostgreSQL or another relational database, including safe schema and data migrations

• Strong testing practices, including integration, regression, and failure-scenario testing

• Experience running services in production, including monitoring, on-call, and incident investigation

• Strong security fundamentals, including secure coding and dependency management

• Daily use of, or a real willingness to use, AI coding tools, with full ownership of anything you submit

• The ability to explain trade-offs clearly, break down complex work, and mentor others

• Clear written and spoken English

Nice to Have

• Experience with PCI DSS or another regulated production environment

• A background in payments or fintech, including payment provider integrations and reconciliation

What's on Offer

• Competitive salary: base pay plus a discretionary annual performance bonus

• Real ownership: join early and help shape the product, the technical direction, and how the team works

• Private health insurance from your first day

• 21 working days of paid annual leave, plus your birthday off

• Flexible working hours and a hybrid working model

• Learning budget for courses and certifications

• Paid access to leading AI coding tools

• High standards, light process, and a collaborative team