Remote Sr. Software Engineer, Fullstack (UK)

• Design, build, and maintain public-facing APIs and Agentic tools that enable enterprise customers to integrate with and extend our 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 our wider engineering organisation.
• Write high-quality code that is reliable, readable, efficient, testable, scalable, and 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.

Technologies:

• AI
• AWS
• Backend
• Cloud
• Datadog
• Docker
• Frontend
• Helm
• Support
• Kubernetes
• React
• Ruby
• SAP
• Security
• Serverless
• TypeScript
• microservices
• NodeJS
• TM1
• Fullstack

More:

We are Firstup, the worlds first intelligent communication platform, on a mission to improve the employee experience at every moment that matters. We serve 40 of the Fortune 100 and reach more than 17 million employees daily, helping companies engage, support, promote, and retain their talent from hire to retire. We offer an excellent PTO program, great health benefits, a casual and friendly environment, remote work, and a leadership team committed to your growth personally and professionally. We value inclusion, curiosity, and people who thrive in a high-growth, fast-changing environment.

• Bachelors 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.
• 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.