Software Engineer, Fullstack UK

Who We Are

At Firstup , our mission is to improve the employee experience at every moment that matters, large and small. As the communication pipeline for the world's workforce, we now serve 40 of the Fortune 100 companies, reaching and connecting more than 17 million employees daily.

Our employees are experts in the employee experience, workforce communications and technology.

Joining Firstup means joining a movement to make work better for every worker. As the world’s first intelligent communication platform, Firstup meaningfully engages employees at every moment from hire to retire, and delivers engagement insights to help companies support, promote and retain their talent. Our movement has taken root and is evident in our world-class customer base. Now we need your help. Ready to make a difference in the world?

Job Summary

The Sr. Software Engineer will join the team responsible for Firstup 's public APIs, Agentic tools, third-party integrations with enterprise systems such as HRIS platforms, and shared platform services. You will deliver innovative, scalable solutions while constantly improving our approach to architecture, scale, availability, and fault-tolerance. You are an active user of Generative AI tools and coding agents, applying them daily to accelerate delivery and improve code quality.

Responsibilities

Contribute to the design, development, and maintenance of public-facing APIs used by enterprise customers.

Build and maintain integrations with external enterprise systems, including HRIS platforms such as Workday, SAP SuccessFactors, and Dayforce.

Support shared platform services used across the engineering organisation.

Write clean, well-tested, and well-documented code, and participate in code reviews.

Work within large-scale multi-tenant cloud services, developing your understanding of scalability and fault-tolerance.

Use Generative AI tools and coding agents in day-to-day workflows to improve code quality and delivery speed.

Collaborate with teammates and cross-functional partners to solve problems and deliver customer value.

Contribute to production health, including on-call rotations and incident response, in a "you build it, you run it" environment.

Identify and help resolve availability, reliability, and performance issues.

Minimum Qualifications

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

3-5 years building reliable, performant applications and microservices.

Proficiency in TypeScript and Node.js. Ruby experience is a plus.

Experience across frontend (React.js), backend, and database layers.

AWS experience, including core compute, storage, and networking services.

Curiosity, a desire to learn, and openness to feedback.

A focus on customer experience in the work you deliver.