Job description Context Collective.work is building the next generation of AI-powered recruitment.
The company supports over 20,000 recruiters and headhunters across France, Belgium, Spain, and EMEA, and is expanding its product and distribution in the UK.
The platform combines a suite of AI agents — from sourcing and outreach to job posting and ATS integrations — with a database of 800M+ professional profiles and a network of 1M+ active candidates .
Missions Build and ship product features across the React frontend and Node.js backend.
Develop scalable APIs, backend services, and integrations with third-party tools, including ATS platforms.
Integrate AI-powered capabilities into intuitive, high-performance user experiences.
Improve application performance, reliability, and code quality.




Collaborate closely with product and engineering teams to deliver features from conception to production.
Tools Environment React Node.js JavaScript/TypeScript AI APIs and LLM integrations (plus) ATS platform integrations Working Conditions Location: Madrid, Spain Type: Freelance / Contract Start date: ASAP Duration and day rate: To be agreed Requirements Strong experience with React , Node.js , and JavaScript/TypeScript Solid understanding of API design , backend architecture , and database integration Experience building and maintaining production-grade web applications Familiarity with AI APIs , LLM integrations , or AI-powered products is a plus A proactive, product-minded engineer who enjoys taking ownership and shipping quickly

📌 Freelance Fullstack Engineer React (Madrid)
🏢 Collective.work
📍 Madrid