Senior Software Engineer

Optimizely; Greater London; Hybrid; GBP 63,000 - 103,000; Full time

Benefits offered by this job

Hybrid work setup

Remote work for UK-based candidates

Job summary

Optimizely in London is seeking a senior software engineer to design, build, and maintain scalable CMS features and integrations. You will work in a cross-functional, agile team on AI-powered content tools and REST APIs.

The role requires ~8+ years in software engineering, strong C#, .NET, React frontend, cloud knowledge, and a mindset for testing and quality. Hybrid London/UK remote options are available.

Qualifications

• ~8+ years of experience in software engineering, flexible depending on experience.
• Strong fundamentals in software design and engineering.
• Experience with C# and .NET, and React on the frontend.
• Experience with CMS platforms, content modelling, or similar domains.
• Experience building and operating cloud-based systems.
• Comfortable using AI tools in the daily workflow for problem solving, learning, and improving code quality and delivery speed, with the ability to guide AI-assisted development using structured instructions to generate code in a controlled and maintainable way.
• Interest or experience in leveraging AI agents to further enhance productivity.
• Strong testing mindset, with a focus on building reliable, well-tested systems and maintaining high code quality.
• Comfortable working in cross-functional, agile teams.
• Strong communication and collaboration skills.
• Bachelor's degree in Computer Science or engineering preferred, or equivalent work experience.

Responsibilities

• Design, build, and maintain scalable, maintainable software systems.
• Develop CMS features, add-ons, APIs, and integrations with external systems.
• Contribute to system design and architectural decisions.
• Ensure product quality through automated testing and operational best practices.
• Own services in production, including monitoring and incident handling.
• Collaborate with product managers, designers, and engineers to deliver features end to end.
• Consider real-world usage and customer needs in technical decisions.
• Mentor other engineers and contribute to knowledge sharing.
• Participate in hiring and help grow the engineering team.

Skills

8+ years experience

Strong software design fundamentals

C# & .NET

React frontend

AI tools usage

AI agents usage

Testing mindset

Cross-functional, agile teams

Communication & collaboration

Bachelors in CS or Engineering

Education

Bachelor's degree in Computer Science or engineering

Tools

CMS platforms

Azure

ASP.NET

REST APIs

React

Cloud

DXP

Job description

Salary: £63,000 - 103,000 per year

Requirements:

• ~8+ years of experience in software engineering, flexible depending on experience
• Strong fundamentals in software design and engineering
• Experience with C# and .NET, and React on the frontend
• Experience with CMS platforms, content modelling, or similar domains
• Experience building and operating cloud-based systems
• Comfortable using AI tools in the daily workflow for problem solving, learning, and improving code quality and delivery speed, with the ability to guide AI-assisted development using structured instructions to generate code in a controlled and maintainable way
• Interest or experience in leveraging AI agents to further enhance productivity
• Strong testing mindset, with a focus on building reliable, well-tested systems and maintaining high code quality
• Comfortable working in cross-functional, agile teams
• Strong communication and collaboration skills
• Bachelors degree in Computer Science or engineering preferred, or equivalent work experience

Responsibilities:

• Design, build, and maintain scalable, maintainable software systems
• Develop CMS features, add-ons, APIs, and integrations with external systems
• Contribute to system design and architectural decisions
• Ensure product quality through automated testing and operational best practices
• Own services in production, including monitoring and incident handling
• Collaborate with product managers, designers, and engineers to deliver features end to end
• Consider real-world usage and customer needs in technical decisions
• Mentor other engineers and contribute to knowledge sharing
• Participate in hiring and help grow the engineering team

Technologies:

• AI
• AI Agents
• C#
• Cloud
• CMS
• Frontend
• REST
• React
• ASP.NET
• Azure
• DXP
• Figma
• Flow
• Support
• LLM
• Marketing
• PaaS
• RAG
• SQL
• UX UI Design

More:

We are Optimizely, a global MarTech company with 1,600+ Optimizers across 12 global offices, serving 10,000+ brands including H&M, PayPal, and Zoom. We build AI-powered content creation, a world-class CMS, and an experimentation platform that helps modern marketers create, manage, publish, and optimize digital experiences. Our CMS team in the UK works on a core part of our platform, including extensible CMS capabilities, integrations, forms, Language Manager, AI tools and agents, REST APIs, and connections to other Optimizely products and external systems. We offer a London office, a hybrid setup, and fully remote working for UK-based candidates outside London, within a collaborative global environment that values open communication, shared ownership, and work-life balance.

last updated 36 week of 2026