Sr. Software Engineer

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

• 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.