Full-Time

AI Engineer

Posted on 10/30/2025

Prolific

Prolific

1,001-5,000 employees

Platform matching researchers with study participants

No salary listed

Remote in UK

Remote

Category
AI & Machine Learning (2)
,
Required Skills
LLM
FastAPI
Python
Tensorflow
Pytorch
Machine Learning
RAG
DevOps
Django
Requirements
  • A strong track record of designing, building, and shipping AI-powered features that have solved real business problems.
  • An inquisitive and experimental mindset, with a passion for tackling ambiguous problems that may not have established solutions.
  • Deep practical knowledge of the modern AI engineering stack (e.g., RAG, vector databases, prompt engineering, fine-tuning techniques, and evaluation frameworks).
  • The ability to thoughtfully balance cutting-edge research with the practical constraints of production reliability and scalability.
  • Deep expertise in one, or both of the following areas: Software Engineering & Systems Design: Expertise in Python and experience building scalable services (e.g., using FastAPI, Django). You have a strong command of system design, infrastructure, and CI/CD pipelines, and you're comfortable taking a feature from concept to deployment.
  • Machine Learning Engineering & Research: A comprehensive background in machine learning, with deep experience in ML frameworks (e.g., PyTorch, TensorFlow, Hugging Face) and a strong grasp of the underlying theory behind the models and techniques you use.
Responsibilities
  • Architect & Build: Lead the design and implementation of production-grade AI systems that enhance how human feedback is collected, validated, and utilised across our platform.
  • Solve Core Challenges: Develop sophisticated systems for fraud detection, quality assurance, and intelligent participant-to-task matching using techniques like vector search and advanced profile representation.
  • Innovate with LLMs: Create and deploy AI agents and systems with immediate product impact - from basic automated data tagging, to advanced features like LLM-based evaluation judges, all the way to experimental ideas such as synthetic personas.
  • Drive Technical Strategy: Provide technical leadership and mentorship on the practical application of AI/LLM techniques, defining best practices for everything from prompt engineering to fine-tuning and RAG.
  • Ensure Reliability: Implement and own LLM observability and evaluation systems to ensure our AI features are reliable, performant, and continuously improving.
  • Collaborate Cross-Functionally: Work closely with data scientists, platform engineers, and research teams to build cohesive, end-to-end solutions that push the boundaries of human-AI interaction.
Desired Qualifications
  • Experience with modern LLM orchestration frameworks (e.g., LangChain, LlamaIndex, DSPy, LangGraph).
  • Experience in agentic system design and tool calling (Adk, A2A, MCP, etc.)
  • Prior work on human-in-the-loop systems, data annotation platforms, or reinforcement learning from human feedback (RLHF).
  • An interest or experience in synthetic data, human-in-the-loop systems, or AI alignment.
  • Experience building robust monitoring and observability for AI/ML systems in production.

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

Simplify Jobs

Simplify's Take

What believers are saying

  • AI training demand surge drives growth as companies require reliable human data for model development and testing.
  • Custom screening automation and participant allowlists reduce researcher friction and increase platform stickiness.
  • Series A funding enables geographic expansion and product development to capture emerging markets beyond academia.

What critics are saying

  • Scale AI and MTurk's cost advantage erodes market share in price-sensitive AI training and annotation segments.
  • EU AI Act enforcement starting August 2026 imposes strict compliance costs and participant data audit requirements.
  • Fraud rings exploiting screener systems damage researcher trust and inflate participant rejection rates significantly.

What makes Prolific unique

  • Prolific's reputation-based system and 120,000 vetted participants ensure higher data quality than competitors like MTurk.
  • Advanced screener logic with AND/OR conditions enables precise participant targeting for complex research requirements.
  • Established relationships with Google, Stanford, Oxford, and European Commission provide credibility and recurring revenue.

Help us improve and share your feedback! Did you find this helpful?

Benefits

Remote Work Options

Growth & Insights and Company News

Headcount

6 month growth

-10%

1 year growth

-11%

2 year growth

-13%
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