Senior Full-Stack Engineer — Remote, High-Impact SaaS

Firstup; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

PTO program

Health benefits

Casual, friendly environment

Remote work options

Growth opportunities

Job summary

Firstup is seeking a Senior Full Stack Engineer who thrives at the intersection of craft and scale. You will design and deliver large-scale, multi-tenant cloud services with a focus on availability, fault-tolerance, and clean architecture.

You will define engineering quality and mentor others to raise the bar across teams. You will own end-to-end development of SaaS applications, collaborate with Product and Design, and champion testing and best practices to ship robust features in a fast-paced

Qualifications

• Bachelor's degree in Computer Science or equivalent experience.
• 8+ years building reliable, production-grade applications and microservices.
• Full-stack fluency across frontend, backend and database layers.

Responsibilities

• Build and own scalable SaaS applications end-to-end — frontend, backend, and data layers.
• Design future-ready architectures and close gaps before they become problems.
• Drive system availability and performance across the stack and advocate for efficiency.
• Champion a rigorous 'shift-left' testing culture with unit, integration and contract tests.
• Leverage AI-assisted tools to accelerate development while maintaining code correctness.
• Drive team-wide best practices and mentor engineers to elevate quality.
• Collaborate with Product and Design to translate requirements into intuitive UI.
• Promote engineering standards and solve high-impact problems across teams.

Skills

Full-stack fluency

Distributed systems

Multi-tenant SaaS

On-call / incident response

Leadership & mentoring

Education

Bachelor's degree in Computer Science

Tools

Ruby on Rails

TypeScript

Node.js

Go

React.js

Job description

Firstup is seeking a Senior Full Stack Engineer who thrives at the intersection of craft and scale. You will design and deliver large-scale, multi-tenant cloud services with a focus on availability, fault-tolerance, and clean architecture.

You will define engineering quality and mentor others to raise the bar across teams. You will own end-to-end development of SaaS applications, collaborate with Product and Design, and champion testing and best practices to ship robust features in a fast-paced