Senior Engineer, Platform (C#)

Oak Engage; North East; Hybrid; GBP 65,000 - 85,000; Full time

Job summary

A forward-thinking SaaS company is seeking a Senior Back-End Engineer to enhance their server-side systems using C#/.NET. This strategic role involves designing high-availability services and guiding architectural decisions for their growing customer base. Ideal candidates will have 5+ years in back-end development and strong API design skills. Join a mission-led company offering hybrid working options, competitive benefits, and the chance to work with major brands.

Benefits

Private health insurance

Life insurance

Employee Assistance Programme

Gym contribution

Travel allowance

Enhanced maternity/paternity leave

Generous holiday policy

Regular team socials

Qualifications

• 5+ years in back-end development with C#/.NET and experience at scale.
• Deep understanding of software design patterns and secure development.
• Experience designing APIs with a strong focus on security and best practices.
• Comfortable working with CI/CD pipelines, Docker, and cloud infrastructure.

Responsibilities

• Design and develop robust back-end services and APIs using C# and .NET Core/.NET 6+.
• Optimise system performance, security, and scalability.
• Guide architectural decisions around microservices and data storage.
• Collaborate with product to shape technical strategy.

Skills

C#/.NET

API design

CI/CD

Docker

Cloud infrastructure

Agile environments

Software design patterns

Systems architecture

Security best practices

Technical collaboration

Tools

Azure

Job description

Location: Hybrid, Newcastle or Remote (UK Based)
Reports to: Engineering Manager
Type: Full-time

Join Oak Engage – Where Communication Meets Connection

At Oak Engage, we’re on an exciting growth journey—backed by a major investment from NorthEdge to scale our impact and redefine the future of employee engagement. Trusted by some of the UK’s biggest brands, including Aldi, Five Guys, and ITV, we help organisations connect, engage, and empower their people through smarter, more personalised internal communication. With our next stage of expansion underway, we’re building a team of bold, ambitious thinkers ready to make their mark at a high-growth, purpose-driven SaaS company. If you’re looking to shape the future of work and grow alongside a company that’s going places, now’s the time to join Oak.

About the Role

We’re looking for a Senior Back-End Engineer with deep expertise in C#/.NET to drive the evolution of Oak’s server-side systems. You’ll take ownership of designing and delivering high-availability, high-performance services, working at the core of a product used by some of the UK’s biggest brands.

This is a strategic, hands-on role perfect for someone who enjoys solving complex technical challenges, shaping architecture, and supporting product growth at scale.

What You’ll Do

• Design and develop robust back-end services and APIs using C# and .NET Core/.NET 6+
• Optimise system performance, security, and scalability for a growing customer base
• Guide architectural decisions around microservices, data storage, and integrations
• Collaborate with product and other stakeholders to shape Oak's technical strategy and roadmap.
• Mentor junior engineers and contribute to technical best practices
• Drive automation, observability, and CI/CD maturity

What We’re Looking For

• 5+ years in back-end development with C#/.NET and experience at scale
• Deep understanding of software design patterns, systems architecture, and secure development
• "Experience designing APIs with a strong focus on security and best practices."
• "Comfortable working with CI/CD pipelines, Docker, and cloud infrastructure; Azure experience is advantageous."
• Experience working in agile environments with modern DevOps toolchains

• Strong communicator and technical collaborator
  

Why Join Oak?

• A meaningful role in a mission-led SaaS company with strong growth and product-market fit
• The chance to work with household brands and solve real-world enterprise challenges
• Flexible hybrid or remote working options
• Private health insurance, life insurance, and Employee Assistance Programme (EAP)
• Gym contribution and travel allowance
• Enhanced maternity, paternity, and discretionary leave
• Generous holiday policy (25 days + Bank Holidays + additional discretionary days)
• Regular team socials and a positive, collaborative culture

Our Recruitment Process

Hiring Manager Interview

• Deep dive into architecture, problem-solving, and team contributions
• Assess communication and curiosity

Technical Task or Live Pairing

• Realistic, time-bound task or live coding session
• Use structured rubric for fairness (avoid freeform “whiteboarding”)
• "Focus on team collaboration, code quality, and feedback"

Peer Technical Panel/Culture Fit / CTO Chat - In person at our NCL HQ

• Includes cross-functional devs, product manager or designer
• Assess long-term growth potential and alignment with tech principles
• Opportunity for candidate to ask strategic questions

Equality & Diversity at Oak

At Oak, we’re committed to building a diverse and inclusive workplace where everyone feels welcome, supported, and able to thrive.

We believe that different perspectives make us stronger, and we actively encourage applications from people of all backgrounds, experiences, and identities — including, but not limited to, race, ethnicity, gender, age, disability, sexual orientation, and socio-economic status.

We are an equal opportunities employer. All hiring decisions are based on business needs, role requirements, and individual qualifications — without bias or discrimination.

If you require any adjustments to the interview process or the role itself to support accessibility, please let us know — we’re happy to help.