Senior Javascript Developer Jobs in Everett, WA (NOW HIRING)

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.

We're looking for JavaScript Experts to join our Expert Network to help train and evaluate cutting-edge AI models using real engineering expertise. If you have the necessary experience, we'll send you a quick 10- to 15-minute test to assess your skills and suitability for AI tasks. If successful, you'll be invited to join Prolific as a participant, where you'll get paid to train and evaluate powerful AI models.

Researchers looking for your skills tend to pay up to $50 per hour. You must be prepared to complete paid tasks that require one hour of uninterrupted work, though many are shorter.

• Education: a BS, MS, or PhD in Computer Science, Software Engineering, or a closely related technical field.
• Professional Experience: professional experience building scalable web applications using JavaScript/TypeScript.
• Coding Proficiency: ability to solve LeetCode Medium to Hard-level problems in JavaScript independently.
• Deep Domain Knowledge: expert understanding of the Event Loop, closures, prototypical inheritance, and asynchronous patterns (Promises, async/await).
• Code Quality: a high standard for clean code, including modularity, readability, and adherence to modern ES6+ standards.
• Attention to Detail: ability to spot subtle logical flaws, memory leaks, or security vulnerabilities (e.g., XSS, prototype pollution) in model-generated code.

What you'll be doing in the role

• Evaluate Code Accuracy: review AI-generated JavaScript and TypeScript code for functional correctness and adherence to best practices.
• Validate Logic & Reasoning: audit the step-by-step explanations provided by AI for complex algorithmic solutions to ensure they are logically sound.
• Conduct Execution Testing: execute model-generated scripts in appropriate environments (Node.js or Browser consoles) to verify performance and output.
• Annotate Model Performance: identify areas where a model provides inefficient solutions, deprecated syntax, or hallucinated library methods.
• Refine Technical Logic: provide structured feedback on how models reason through frontend or backend architecture discussions.

• Core Language: expert mastery of JavaScript (ES6+) and TypeScript.
• Frameworks: extensive experience with React, Node.js, Vue, or Angular.
• Testing & Tools: proficiency with Jest, Cypress, Webpack, and Vite.
• Backend & API: strong understanding of RESTful APIs, GraphQL, and server-side logic in a Node environment.

Joining our Expert Network will give you the chance to influence the AI models of the future using professional 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.

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