Sr. Software Engineer, Fullstack (UK)

Team: Product Engineering

Location: Remote - UK

Commitment: Full-time

Workplace Type: remote

Responsibilities

• Design, build, and maintain public-facing APIs and Agentic tools that enable enterprise customers to integrate with and extend the Firstup platform.

• Develop and own integrations with external enterprise systems, including HRIS platforms such as Workday, SAP SuccessFactors, and Dayforce.

• Build and maintain shared platform services used across the wider engineering organisation.

• Write high-quality code (reliable, readable, efficient, testable, scalable, maintainable), provide thorough code reviews, and create comprehensive tests and documentation.

• Apply broad, in-depth knowledge to develop and maintain large-scale multi-tenant services in the cloud.

• Actively use Generative AI tools and coding agents in day-to-day workflows to improve code quality and accelerate delivery.

• Collaborate across teams on industry standards and best practices to help others solve complex problems.

• Design future-ready solutions and address architectural gaps using modern microservices and cloud-native patterns.

• Own production health for your services, contributing to on-call rotations, incident response, and post-incident reviews in a "you build it, you run it" environment.

• Identify, analyse, and resolve system availability, reliability, and performance issues, contributing to observability and resiliency improvements.

• Partner with Product Management and Design to translate business requirements into scalable technical solutions.

Minimum Qualifications

• Bachelor's degree in Computer Science or related field, or equivalent experience.

• 5+ years building reliable, performant applications and microservices.

• Strong proficiency in TypeScript and Node.js. Ruby experience is a plus.

• Proven full-stack experience across frontend (React.js), backend, and database layers.

• Technical depth in at least one specialisation: networking, security, serverless, event streams, or similar.

• Strong AWS experience, including compute, storage, networking, and monitoring.

• Excitement to build beautiful, intuitive products with a strong customer focus.

• Innate curiosity and a desire to learn and teach.

Preferred Qualifications:

• Experience building and maintaining integrations with HRIS platforms such as Workday, SAP SuccessFactors, Dayforce, or similar enterprise HR systems.

• Experience with Kubernetes, Docker, and Helm.

• Experience with Datadog or similar observability and monitoring platforms.

• Demonstrated use of Generative AI tools or coding agents in development workflows.

• Experience in enterprise SaaS organisations, particularly HR Tech or regulated domains.

• Familiarity with ML/AI integration in production systems.

• Open-source contributions or a history of side projects.