Senior Full Stack Engineer

Company: Harnham
Apply for the Senior Full Stack Engineer
Location: London
Job Description:

London, 2 days per week in the office

The Opportunity

Our client are hiring three Senior Software Engineers to join a growing engineering function that builds technology powering large-scale advertising and media platforms.

This is a hands‑on senior role for engineers who enjoy thinking about the “why”, not just the “how”. You’ll help shape technical decisions, guide less experienced engineers, and contribute to building well‑designed, scalable systems used across major advertising campaigns.

The Challenge

The team is looking for engineers who can:

  • Provide technical direction and sound judgement
  • Think critically about priorities, architecture, trade‑offs, and impact
  • Ask the right questions before diving into implementation
  • Collaborate effectively and feel comfortable discussing solutions rather than following scripts

What They’re Looking For

Experience

  • Ideally 5+ years of commercial experience
  • Experience with NodeJs and ReactJs
  • Industry is open (financial services experience may not be the best fit)

Mindset

  • Self‑starter who can take ownership
  • Comfortable leading solutions without formal authority
  • Analytical, thoughtful, and curious
  • Collaborative rather than siloed

Interview Process

  • 1‑hour competency‑based interview with the Engineering Director
  • Final onsite interview – problem‑solving session using a whiteboard

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Posted: May 19th, 2026