HTML/CSS - Senior Developers - AI Training - Belfast, UK
Likely
Sponsorship likelihood
This employer has issued visas recently
Not disclosed
Salary
Not disclosed by employer
£54,700
Going rate
Skilled Worker going rate
This role likely qualifies for a Skilled Worker visa
SOC 2134 (85% match) is an eligible occupation, with a going rate of £54,700, and Prolific is a licensed sponsor. That is our reading of the rules. Whether they issue a Certificate of Sponsorship is still their call.
This could also be SOC 2141 (Web design professionals, Web design professionals also design and develop websites and applications). We read the code off the advert, so it is our best guess, not the employer's.
New graduate or PhD holder? Pick one of the lower rates.
What each route needs for this job
| Occupation code | New entrant 70% of going rate | STEM PhD 80% of going rate | Relevant PhD 90% of going rate | Standard rate 100% of going rate |
|---|---|---|---|---|
2134 Programmers and software development professionals Most likely code | £38,300 | £43,700 | £49,200 | £54,700 |
2141 Web design professionals Also possible | £33,400 | £35,100 | £39,400 | £43,800 |
We use the lowest threshold across the plausible codes. Likelihood is Possible at most when the pay clears only a lower rate, or only under a less likely code. How the Home Office picks the code
About the role
About Prolific
Prolific is not just another player in the AI space – we are building the biggest pool of quality human data in the world.
Over 35,000 AI developers, researchers, and organizations use Prolific to gather data from paid study participants with a wide variety of experiences, knowledge, and skills.
The role
We're looking for Senior HTML/CSS Developers to join our Expert Network to help train and evaluate cutting-edge AI models. If you have a background in Software Engineering or Frontend Development, we'll send you a quick 10- to 15-minute test to assess your skills. If successful, you'll be invited to join Prolific as a participant, where you'll get paid to help AI understand and produce high-quality frontend code and design implementation.
Researchers looking for your skills tend to pay up to $40/hr, depending on skills and experience. You must be prepared to complete paid tasks that require one hour of uninterrupted work, though many are shorter.
What you'll bring
- Educational Background: a BSc or higher in Computer Science, Software Engineering, Web Development, or a closely related technical field.
- Professional Experience: real-world experience as a Senior Frontend Developer or UI Engineer specialising in HTML/CSS.
- Coding Proficiency: ability to independently build complex, responsive layouts and components without relying on frameworks or libraries.
- Deep Domain Knowledge: expert understanding of the CSS cascade, specificity, the box model, Flexbox, CSS Grid, accessibility standards (WCAG), and cross-browser compatibility.
- Code Quality: a high standard for clean, semantic markup and maintainable CSS, including adherence to BEM methodology, design tokens, and modern CSS standards.
- Evaluate Code Accuracy: review AI-generated HTML/CSS for functional correctness, semantic structure, and adherence to best practices.
- Validate Logic & Reasoning: audit the step-by-step explanations provided by AI for layout solutions and styling approaches to ensure they are technically sound.
- Conduct Execution Testing: render model-generated markup and stylesheets in appropriate environments to verify visual output and cross-browser behaviour.
- Annotate Model Performance: identify areas where a model produces inaccessible markup, inefficient selectors, deprecated attributes, or hallucinated CSS properties.
- Refine Technical Logic: provide structured feedback on how models reason through responsive design, component architecture, or design system implementation.
- Core Languages: expert mastery of HTML5 and CSS3/4, including custom properties, animations, and modern layout systems.
- Frameworks & Methodologies: extensive experience with Tailwind CSS, SASS/SCSS, or CSS Modules, and familiarity with component-driven design systems.
- Testing & Tools: proficiency with browser DevTools, accessibility auditing tools (e.g., axe, Lighthouse), and cross-browser testing platforms.
Joining our platform as a Prolific participant will give you the chance to influence the AI models of the future using professional legal expertise. Once you pass our assessment, you can join Prolific in just 15 minutes, and start enjoying competitive pay rates, flexible hours, and the ability to work from home.
We've built a unique platform that connects researchers and companies with a global pool of participants, enabling the collection of high-quality, ethically sourced human behavioural data and feedback. This data is the cornerstone of developing more accurate, nuanced, and aligned AI systems.
We believe that the next leap in AI capabilities won't come solely from scaling existing models, but from integrating diverse human perspectives and behaviours into AI development. By providing this crucial human data infrastructure, Prolific is positioning itself at the forefront of the next wave of AI innovation – one that reflects the breadth and the best of humanity.
Links to more information on Prolific
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Privacy Statement
By submitting your application, you agree that Prolific may collect your personal data for recruiting and global organisation planning. Prolific's Candidate Privacy Notice explains what personal information Prolific may process, where Prolific may process your personal information, its purposes for processing your personal information, and the rights you can exercise over Prolific use of your personal personal information.
This description is the source posting as it read when we added it. We are not affiliated with Prolific, so check their own site for the current details.
Where this offer sits in the market
Programmers and software development professionals (SOC 2134) · UK · ONS ASHE 2025 · basic pay · ~399k in sample- Middle half £42,536–76,752
- Median £56,784
- Going rate £54,700
- Threshold £41,700
- New entrant £38,300–49,200
Similar sponsored roles
See all UK visa jobsNo close matches live right now.
Browse more sponsored jobs at ProlificAbout sponsorship for this role
Does this job guarantee visa sponsorship?
Not necessarily. Prolific holds a sponsor licence, but sponsorship for a specific hire is always the employer's decision. Be upfront in your application that you'll require it.
What salary is needed for this role to be eligible?
The offer must clear both the general threshold and the SOC 2134 going rate of £54,700. New-entrant and shortage discounts can lower it.