Senior Full Stack Engineer

Senior Full Stack Engineer
Salary £80k to £85k + Bonus and excellent pension/ benefits
Location: Central London
About the client
Our client is an infrastructure communications technology company providing end-to-end fibre solutions and now Cloud solutions, Wi-Fi, Firewalls/Security, SD WAN, Managed LAN and UC services for businesses and wholesale/carrier/channel organisations across London.
What you will do:
We are looking for a Senior Full Stack Engineer to own end-to-end delivery of critical features, drive architectural excellence, and establish best practices. You’ll work hands-on across React, Node.js, and Python services, own our CI/CD and DevOps processes, integrate with network-centric systems, and mentor the wider engineering team as we grow.
‍Key responsibilities:

• Architect, build & implement scalable features in our React frontend and Node.js / Python backend (FastAPI, Celery)
  
• Design integrations with network devices, IPAM, monitoring platforms, Wi-Fi authentication systems, CRMs and partnered PropTech tools
  
• Continually hone and perfect our homegrown DevOps and CI/CD processes by further developing GitHub Actions pipelines, Terraform definitions and observability integrations.
  
• Ensure quality & reliability: establish testing best practices (unit, integration, end-to-end), conduct code reviews and demand high quality standards
  
• Shape and refine our cloud-native platform to optimise performance, security and scalability
  
• Mentor & lead intermediate developers, imparting knowledge and fostering a culture of clean code, peer review and shared ownership.
  
• Collaborate cross-functionally with product, operations and customer success to translate requirements into robust technical solutions.
  A good fit candidate will have:
  
• 5+ years hands-on as a full stack engineer in a SaaS environment
  
• Expert in React (hooks, state management, performance)
  
• Strong backend skills in Node.js (Express) and Python (FastAPI, Celery)
  
• Deep familiarity with Microsoft Azure (App Services, Functions, networking)
  
• Proven experience working with network-focused systems (SNMP, IPAM, CLI automation)
  
• Solid understanding of Auth0 (or similar OAuth/OIDC) and secure authentication flows.
  
• Skilled with GitHub and GitHub Actions for automated CI/CD.
  
• Experience with infrastructure as code (ARM templates, Terraform, Bicep).
  
• Comfortable writing and maintaining tests (unit, integration, e2e).
  
• Excellent communication, problem-solving skills and ability to thrive in a fast-paced startup.
  Desirable Experience:
  
• Background in network engineering or close collaboration with network operations teams.
  
• Experience building platform integrations and/or asynchronous automation systems.
  
• Open-source contributions in related domains.
  
• You’ve worked at an early-stage startup before and understand what “hands-on” really means