Frontend Engineer (Websites & Systems)

Demandflow; United Kingdom; Remote; GBP 65,000 - 95,000; Full time

Benefits offered by this job

Performance bonus

Frontier tools access

Dedicated learning time

Regular feedback

25 days leave

Fully remote with flexible schedule

Job summary

Demandflow is hiring to build high-performing B2B websites and the systems behind them. You’ll own architecture decisions across content, data-fetching and integrations, working primarily with Astro and Next.js, and maintaining Webflow sites.

Expect collaboration across GMT/EST and a fully remote role. You’ll shape maintainable codebases, CMS models, and integrations while improving test, release, and deployment practices.

Qualifications

• Strong HTML, CSS, JavaScript and TypeScript with React; debugging production sites.
• Experience structuring maintainable website codebases and explaining trade-offs.
• Headless CMS and content modelling; editors’ workflow understood.
• APIs, webhooks and third-party integrations; validation and secure configurations.
• Performance and accessibility knowledge including Core Web Vitals; testing across devices.
• Technical SEO and AEO knowledge: rendering, canonical URLs and structured data.
• AI coding workflow familiarity; Codex/Claude in the workflow; rigorous debugging.
• Clear communication with designers and project leads; turning constraints into usable solutions.

Responsibilities

• Own website architecture: choose rendering and data-fetching strategies; create reusable components.
• Model CMS content, build templates, previews, and connect forms and analytics.
• Improve build/release processes: shared foundations, internal tools, and deployment checks.
• Ensure technical quality across real user journeys; review changes and manage risks.

Skills

HTML

CSS

JavaScript

TypeScript

React

Tools

Astro

Next.js

Webflow

Git

APIs

Job description

Build the technical foundations that let B2B marketing websites perform, evolve and stay useful to the teams running them.

The opportunity

Build high-performing B2B websites and the systems that make them useful to marketing teams. You’ll own technical decisions across architecture, content and integrations, and help improve how we build, test and release the work.

You’ll work primarily with Astro and Next.js, alongside our work building and maintaining Webflow sites. Codex and Claude support the workflow. You own the technical choices and verify the result.

Working hours: Availability to collaborate across GMT and EST time zones

What you’ll do

• Own the website architecture: Choose the right architecture, rendering and data-fetching approach. Create maintainable code and reusable components with designers and Design Engineers, keeping the intended experience intact.
• Make the system work for marketing: Model CMS content, build templates and previews, and connect forms, analytics and marketing tools. Handle validation, failure states and sensitive configuration carefully.
• Improve how we build and release: Develop shared foundations, internal tools and component libraries. Strengthen preview deployments, automated checks and release processes, then document decisions and hand over the work clearly.
• Own the technical quality: Investigate performance and accessibility across real user journeys. Build crawlable content, redirects, metadata and accurate structured data with the growth team. Review AI-assisted code, test fixes and keep Project Leads informed of dependencies and risks.

The expertise you’ll bring

• Strong HTML, CSS, JavaScript, TypeScript and React, including debugging production sites. You’ve used Astro and Next.js and understand rendering, routing and server/browser boundaries.
• Experience structuring maintainable website codebases and explaining technical trade-offs.
• Headless CMS and content modelling experience, with a clear understanding of how editors use the system.
• APIs, webhooks and third-party integrations, including validation, error handling and secure configuration. You’re comfortable with Git, deployments and automated tests.
• Strong performance and accessibility knowledge, including Core Web Vitals and testing across devices and input methods.
• Working technical SEO and AEO knowledge: rendering, canonical URLs and structured data that accurately reflects the page.
• An established AI coding workflow and the judgement to reason through choices, review and debug code, and verify behaviour. Codex and Claude will be part of your work.
• Attention to visual detail and clear communication with designers and Project Leads, turning constraints into useful recommendations.

Useful additional experience

• Experience building or maintaining websites in Webflow.
• Shared systems for multiple websites, brands or regions.
• Building internal tools, developer utilities or reusable project foundations.
• Website migrations, including moves from Webflow or another managed platform into a codebase.
• Marketing integrations, conversion measurement or experimentation tools.
• Agency work with B2B, SaaS or technology companies.

How we’ll help you grow

Own technical work across websites and the systems behind them. Learn alongside creative developers and growth specialists, and help shape our architecture, engineering standards and use of AI.

What we offer

• Performance bonuses and a clear path to promotion.
• Access to frontier tools.
• Dedicated learning time, funded development and regular feedback.
• Work with specialists across brand, design, development and growth.
• 25 days’ paid leave, plus Christmas time off.
• Fully remote, with a flexible schedule around your role’s collaboration hours.