P

Prolific

Platform matching researchers with study participants

Javascript – Senior Developers - AI Training, Canterbury, UK

Full-TimeUpdated on 10/23/2026
$50/hr
Senior
Bachelor's, Master's, PhD
Remote in UK
Remote
QA & TestingManual & Functional QA

About the job

Requirements
  • A BS, MS, or PhD in Computer Science, Software Engineering, or a closely related technical field.
  • Professional experience building scalable web applications using JavaScript or TypeScript.
  • Ability to solve LeetCode Medium to Hard-level problems in JavaScript independently.
  • Expert understanding of the Event Loop, closures, prototypical inheritance, and asynchronous patterns including Promises and async/await.
  • A high standard for clean code, including modularity, readability, and adherence to modern ES6+ standards.
  • Ability to identify subtle logical flaws, memory leaks, or security vulnerabilities such as cross-site scripting and prototype pollution.
  • Expert mastery of JavaScript and TypeScript.
  • Extensive experience with React, Node.js, Vue, or Angular.
  • Proficiency with Jest, Cypress, Webpack, and Vite.
  • Strong understanding of RESTful APIs, GraphQL, and server-side logic in a Node environment.
Responsibilities
  • Review AI-generated JavaScript and TypeScript code for functional correctness and adherence to best practices.
  • Audit step-by-step explanations provided by AI for complex algorithmic solutions to ensure they are logically sound.
  • Execute model-generated scripts in appropriate environments, including Node.js or browser consoles, to verify performance and output.
  • Identify areas where a model provides inefficient solutions, deprecated syntax, or hallucinated library methods.
  • Provide structured feedback on how models reason through frontend or backend architecture discussions.

About the company

Prolific operates an online research platform that connects researchers with a global pool of vetted participants. Researchers post studies and set demographic criteria to recruit eligible participants, who complete surveys and other research tasks to earn compensation. The platform uses a reputation-based system to ensure data quality from both researchers and participants. Clients include academic institutions, businesses, and individual researchers, making Prolific a centralized marketplace for human data in online research. The business model charges researchers a commission for each study conducted on the platform, covering participant recruitment, study management, and platform upkeep. Overall, Prolific aims to provide a reliable, efficient way to collect high-quality data for research and market insights.

Company Size

1,001-5,000

Company Stage

Series A

Total Funding

$33.3M

Headquarters

London, United Kingdom

Founded

2014

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Simplify's Take

What believers are saying

  • Prolific reported 380,000 studies and tasks in 2025, plus 8 million participant hours.
  • Its March 2025 AI Task Builder and tasker pool expanded demand beyond academia.
  • Prolific claims 300,000+ active participants and a million-person waitlist, supporting fast fulfillment.

What critics are saying

  • Toloka raised $72 million in May 2025, intensifying competition for AI evaluation budgets.
  • Prolific flagged 0.99% of participants for AI-generated responses in September 2025, showing fraud pressure.
  • If frontier labs build captive panels by 2027, Prolific loses its core network advantage.

What makes Prolific unique

  • Prolific offers 300,000+ verified participants across 80+ languages, with 40+ Protocol checks.
  • Its self-serve API and transparent pricing beat managed-service black boxes for researchers.
  • HUMAINE, launched December 2025, turns real-person AI evaluation into a proprietary benchmarking layer.

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Benefits

  • Remote Work Options

Growth & Insights and Company News

6 month growth

12%

1 year growth

1%

2 year growth

0%
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Jul 14th, 2023
Prolific raises £25m in funding

Prolific, a London, UK-based provider of a platform that matches AI developers with engaged and verified people, raised £25M in funding.

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Jul 12th, 2023
Chicago News Daily - Prolific raises $32M to use people to train and test AI models

Prolific, a company that was founded to source verified data from human participants, said today that it has raised $32 million in a Series A funding round co-led by Partech and Oxford Science …

Tech Company News
Jul 12th, 2023
Prolific secures $32M funding to enhance AI Training and Testing

London-based startup Prolific has raised $32 million to further develop its unique system that uses a network of 120,000 human participants to train and stress-test AI models.

TechCrunch
Jul 11th, 2023
Prolific Raises $32M To Train And Stress-Test Ai Models Using Its Network Of 120K People

AI, when it works well, can feel like magic, but all too often AI-based systems don’t work as they should: If the data used to train models is not deep, wide and reliable enough, any kind of curveball can send that AI in the wrong direction. A London startup called Prolific has built a system it believes can help head off that issue, by tapping a network of 120,000 human participants to inform and stress test AI models. And in a sign of demand for its services, Prolific has now raised some funding — £25 million ($32 million) — to expand its operations.The round was co-led by Partech and Oxford Science Enterprises (OSE).Prolific was founded in 2014 and already counts organizations like Google, Stanford University, the University of Oxford, King’s College London and the European Commission among its customers, using its network of participants to test new products, train AI systems in areas like eye tracking and determine whether their human-facing AI applications are working as their creators want them to. Up to now, it’s been revenue from users like these that have helped Prolific grow. In fact, the only money Prolific had raised prior to this round was a seed round of $1.4 million it got after going through YC. (Yes, it was profitable; no longer now that it’s taking VC money and investing in growth.)“We’ve seen incredible traction recently, and have a huge opportunity in front of us so are taking on this new funding to supercharge our efforts and expand our product, and range of participants, much faster than we could have without it,” Phelim Bradley, the founder and CEO, said over email to TechCrunch.The company was conceived initially not out of a specific need in the world of AI, but out of a general problem that researchers often face with panels for anything, something Bradley identified in his own academic work (his background, before Prolific, was in computational biology and physics).In short, it’s a challenge to find comprehensive cross sections of people to respond to questions, and nearly impossible to do so in a timely manner