> Markdown version of [/jobs/ext/3072676-ai-llm-senior-fullstack-engineer-spain-remote-with-english-30-000-60-000-a-year](https://www.wearedevelopers.com/jobs/ext/3072676-ai-llm-senior-fullstack-engineer-spain-remote-with-english-30-000-60-000-a-year). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Ai / Llm Senior Fullstack Engineer (Spain Remote) With English - €30.000 - €60.000 A Year - **Company:** Agileengine - **Location:** Barcelona, Spain (Remote available) - **Salary:** €30,000.0 - €60,000.0 - **Contract:** Permanent contract - **Skills:** Artificial Intelligence, Mobile Application Development, Information Technology Consulting, Mobile Application Software, Node.Js, Software Engineering, ReactJS, Large Language Models, Firebase, Information Technology, Low Latency, React Native - **Published:** September 25, 2026 - **Apply:** https://www.buscojobs.com.es/ai-llm-senior-fullstack-engineer-spain-remote-with-english-%E2%82%AC-30-000-%E2%82%AC-60-000-a-year-en-barcelona-ID-373142139 ## About the Role Overview We are looking for a Senior Full Stack Engineer to join a fast-growing health and wellness platform with millions of users worldwide. You'll work in a cross-functional, agile team, building and improving features for both web and mobile applications. This role offers the opportunity to enhance performance, deliver seamless user experiences, and make a real impact on a product that helps people reach their wellness goals. What you will do Work independently and provide guidance to other team members; Ensure smoothoperation and performance of both web and mobile applications; Identify, troubleshoot, and resolve bugs efficiently; Design,develop, and implement new features across web and mobile platforms. MUST HAVES 5+ years of experience building scalable systems; Solid experience with ReactJS, NodeJS for web, and React Native for mobile development; Proven ability to deliver solutions with high throughput and low latency requirements ; Demonstrated experience designing and implementing complex business solutions ; Abilityto develop features independently without design guidance, taking ownership from concept to implementation; Upper-Intermediate English level. NICE TO HAVES Experience in Startups; Experience with Firebase Functions . PERKS AND BENEFITS Professional growth: Accelerate your professional journey with mentorship, TechTalks, and personalized growth roadmaps. ## Description Full Stack Engineer (Senior/Lead) ID***** AgileEngine is an Inc. **** company that creates award-winning software for Fortune 500 brands and startups across 17+ industries.We rank among the leaders in areas like application development and AI/ML, and our people-first culture has earned us multiple Best Place to Work awards.Overview We are looking for a Senior Full Stack Engineer to join a fast-growing health and wellness platform with millions of users worldwide.You'll work in a cross-functional, agile team, building and improving features for both web and mobile applications.This role offers the opportunity to enhance performance, deliver seamless user experiences, and make a real impact on a product that helps people reach their wellness goals.What you will do Work independently and provide guidance to other team members; Ensure smoothoperation and performance of both web and mobile applications; Identify, troubleshoot, and resolve bugs efficiently; Design,develop, and implement new features across web and mobile platforms.MUST HAVES 5+ years of experience building scalable systems; Solid experience with ReactJS, NodeJS for web, and React Native for mobile development; Proven ability to deliver solutions with high throughput and low latency requirements ; Demonstrated experience designing and implementing complex business solutions ; Abilityto develop features independently without design guidance, taking ownership from concept to implementation; Upper-Intermediate English level.NICE TO HAVES Experience in Startups; Experience with Firebase Functions .PERKS AND BENEFITS Professional growth: Accelerate your professional journey with mentorship, TechTalks, and personalized growth roadmaps.Competitive compensation: We match your ever-growing skills, talent, and contributions with competitive USD-based compensation and budgets for education, fitness, and team activities.A selection of exciting projects: Join projects with modern solutions development and top-tier clients that include Fortune 500 enterprises and leading product brands.Flextime: Tailor your schedule for an optimal work-life balance, with options for working from home or going to the office.Details Seniority level: Mid-Senior level Employment type: Full-time Industries: IT Services and IT Consulting Referrals increase your chances of interviewing at AgileEngine by 2x.Get notified about new Full Stack Engineer jobs in Barcelona, Catalonia, Spain .#J-*****-Ljbffr ## Related Videos - [Your next 10x engineer isn't in your city. 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