Hire the Best JavaScript Developers
in Spain

Looking to seamlessly integrate IT with your business goals - and do it fast? 🚀 Whether you need a full product built from scratch, modernization of a legacy application, or staff augmentation to strengthen your in-house team - we’ve done it all for hundreds of clients worldwide. I lead a team of 200+ vetted in-house engineers across every major web and mobile tech stack, ready to match you with the right expert within 24 hours. When you hire from us, you work directly, 1-on-1, with your chosen engineer - no middle layers, no constant handoffs. We back every engagement with clear guarantees and stay available for support. 🧑‍💻 About Me With 10+ years in IT management and a technical background, I’ve grown from developer to Project Manager, to PMO, to Head of Delivery — overseeing over 680 completed projects on Upwork with a 100% Job Success Score and 80+ Clutch reviews (avg. 4.8★). My specialization is in building self-managed teams that deliver end-to-end - from idea to launch - so you can focus entirely on your business while we handle delivery. 🛠 Areas of Expertise Full-Stack Development: React, Angular, Vue, Node.js, PHP, .NET, Python, Java, Ruby, Scala Frontend Development: React, Next.js, Angular, Vue.js Backend Development: Node.js, Express, Java, .NET, PHP, Python Mobile Development: Swift, Kotlin, React Native, Flutter CMS: WordPress, Shopify, Magento, Drupal, Webflow Specialized Services: DevOps, QA Engineering, UI/UX Design, AI/ML, Blockchain Engagement Models: End-to-end delivery, Legacy app modernization, Staff augmentation Industries: Fintech, eCommerce, Media & Entertainment, Healthcare, Automotive, GIS, Education, and more. 🏆 Key Achievements 680+ projects delivered on Upwork with 100% JSS Scaled teams from 2 to 22 members and built 15+ self-managed teams Guided/participated in 300+ additional projects outside Upwork Top-10 US real estate rentals project & Scrum Master for CIBC (Canada’s largest bank) If you’re looking for a reliable partner who can quickly connect you with top talent and ensure smooth, direct collaboration, let’s talk. Let’s connect and discuss your goals - I can match you with the right specialist and have them start within 24 hours.

👋 Senior Software Engineer with 5+ years of experience designing, modernising, and operating distributed backend systems, cloud platforms, and event-driven services. Recently specialised in Next.js, FastAPI, Supabase, and AWS, supported by a strong background in Java, Spring Boot, Kubernetes, PostgreSQL, Kafka, and cloud-native engineering. Contributed to production platforms processing millions of monthly API requests and more than one million daily events. Delivered measurable improvements in system performance, deployment frequency, scalability, operational resilience, observability, and cloud infrastructure efficiency. 🔥 Experienced in system design, API lifecycle management, asynchronous processing, microservices, production incident resolution, architecture decision records, service-level objectives, security controls, technical reviews, Agile delivery, and collaboration with international engineering, QA, DevOps, security, and product teams. 👍

Frontend developer with 8+ years of experience, specializing in Vue.js and modern JavaScript/TypeScript ecosystems. Freelancing since 2018, building web applications for clients worldwide. Proven track record of inheriting complex legacy codebases and delivering clean, maintainable Vue 3 migrations. Currently integrating AI tooling (Cursor, Claude Code) into development workflows to accelerate delivery while maintaining code quality. Working knowledge of backend technologies (Node.js, NestJS, PHP/Laravel) when full-stack support is needed. Skills Vue 3, Vue 2, Composition API, Options API, TypeScript, JavaScript, Vuetify, Pinia, Vuex, Vue Router, TanStack Query, VueUse, Vite, Webpack, npm, Git, Vitest, Unit Testing, Component Testing, UI & Data Visualization Vuetify, Material Design, Chart.js, Responsive Design, CSS, SCSS/Sass, Ionic (Mobile Development), Auth0, OAuth, REST APIs, Axios, WebSockets, Stripe, Node.js, Express, NestJS, PHP, Laravel, MongoDB, MySQL, Cursor, Claude Code, AI assisted development, AI workflows. Speak spanish and english. Flexible schedule.

⭐️ Speed without cutting corners: working code on time, every time ⭐️ Budget discipline: every billed hour is justified — no filler tasks ⭐️ Business-first thinking: I understand the problem before I write code, so your budget goes into the product, not experiments 👋 Hi! My name is Anton. I'm a React Developer specializing in SaaS, AI-powered web applications, and B2B platforms. My work also spans Full Stack Developer React Node and Front End Developer work — production-ready code, built for founders shipping SaaS, AI, and B2B products, with a React Developer who owns the whole process, 6+ years helping startups and businesses. ⭐ Top Rated Plus 📅 6+ years as a React Developer 📦 70+ projects delivered ⏱️ 5,000+ Upwork hours 🔁 ~70% returning clients ✅ Why hire me as a React Developer ▪ 6+ years as a React Developer across SaaS, AI, and B2B platforms ▪ 70+ delivered projects as a React Developer, plus Full Stack Developer React Node engagements ▪ 5,000+ Upwork hours logged as a React Native Developer, alongside Full Stack Developer React Node builds ▪ ~70% returning clients — a track record built as a React Developer through partnerships lasting months to years ▪ Top Rated Plus status reflects steady delivery as a Front End Developer, with a track record of on-time launches ▪ A React Developer at the core — React, Next.js, and TypeScript power every build I ship ▪ A React Developer who ships production-ready code, whether the job calls for Full Stack Developer React Node or Web Developer work 🏗️ Full-Stack SaaS & B2B Platforms As a React Developer and Full Stack Developer React Node, I build multi-tenant B2B SaaS platforms with React, Next.js, and Node.js — OWASP-compliant authentication, role-based access control, custom workflow logic, and full Stripe billing (Subscriptions and Connect), backed by PostgreSQL via Prisma with REST and GraphQL APIs on AWS. On the AI side, as a Full Stack Developer AI, I build AI-powered SaaS products with the OpenAI and Anthropic APIs — RAG pipelines, embeddings, semantic search, Supabase Realtime streaming, Stripe Checkout, and offline-ready PWAs on Vercel. 🖥️ Front-End & React Development As a Front End Developer React specialist, I deliver Core Web Vitals-optimized, accessible, responsive interfaces with deep App Router, Server Components, SSR/SSG, and ISR experience. Firebase-backed projects get the same coverage as a React Developer Firebase build. Designs handed off from Figma go through me as a Front End Developer Figma-to-code specialist. As a React Developer, my work also covers two-sided marketplaces, e-commerce, booking systems, real-time chat, and analytics dashboards, extending to iOS and Android via React Native App Developer work with React Native and Expo. 🧭 Process Every engagement as a React Developer opens with scoping the business problem, then architecture, build, and testing with Jest, Vitest, or Playwright, Sentry monitoring, and GitHub Actions CI/CD — the same process behind every Full Stack Developer React Node platform and Front End Developer build, clean front-end development from first commit to production deploy. ⚙️ Tech Stack As a React Developer, I build the frontend with React, Next.js, TypeScript, HTML5, CSS 3, and JavaScript — styling with Tailwind CSS or Bootstrap and handling state with Redux or Zustand. The backend runs on Node.js via Express or NestJS, talking to PostgreSQL through Prisma, or Supabase and Firebase for managed auth and real-time. I deploy to AWS or Vercel with GitHub Actions running CI/CD — the same setup any React Developer needs to ship fast. 🧩 Mixed-Stack Support Python, PHP, Laravel, MySQL, MongoDB, Redis, WordPress, Java, FastAPI, jQuery, Vue.js, and Web3 round out the toolkit. As a Python Developer and Python Full Stack Developer, I handle Python-backed services on request. WordPress and Shopify builds run the same way — a WordPress Developer or WordPress Front End Developer handoff, a Full Stack Developer Shopify build, or a Shopify Front End Developer storefront, all delivered dev-ready. As a Mobile App Developer, I pick up inherited code and mixed stacks quickly, with Web Design and Responsive Design principles carrying through every build. 🏭 Industries SaaS & B2B, AI Startups, Marketplaces & E-commerce, Fintech, Healthtech, Ed-tech, and Real estate — where my React Developer and Full Stack Developer React Node work has landed. 🎯 What clients hire me for Scalable web applications, secure REST and GraphQL APIs, high-performance Next.js front-ends, and reliable, production-ready SaaS — that's what clients bring a React Developer on for. Full Stack Developer React Node and Front End Developer let me deliver end to end, backed by 70+ projects, 6+ years, and ~70% returning clients. Building, scaling, or improving a product? I work as a React Developer, backed by Full Stack Developer React Node, Front End Developer, React Native Developer, and Web Developer — let's talk on a quick call. 👇

Senior Vue.js and JavaScript developer with 10+ years of experience building, refactoring, and scaling frontend applications using Vue, Nuxt, React, Angular, and TypeScript. I specialize in frontend architecture, design systems, and legacy codebase refactoring for startups and product-driven teams. A large part of my work involves taking ownership of existing codebases, improving structure and performance, and helping teams move faster without accumulating technical debt. I’ve worked with distributed teams across the US and Europe on SaaS, fintech, and data-driven products — contributing to component libraries, migrating large Vue applications to Nuxt, stabilizing Angular and React systems, and mentoring developers on best practices. What clients typically hire me for: - Refactoring and modernizing legacy frontend codebases - Designing and maintaining scalable design systems and component libraries - Frontend architecture decisions in startups and enterprise - Vue 3 / Nuxt / React / Angular development with TypeScript - Long-term product engineering and technical ownership Core Technology Stack Frontend: JavaScript, TypeScript, Vue 2/3, Nuxt.js, React, Angular, Pinia / Vuex
 Backend: Node.js, REST APIs, Stream API’s , WebSockets
Styling: HTML5, CSS3, SASS, Tailwind CSS, Bootstrap, Shadcn , Lottie-js 
 Product & Analytics: Mixpanel, 
AI Tooling: Cursor, Claude code, AI Agents, Copilot, N8N
 Workflow: Git (GitHub, GitLab, Bitbucket), Jira, Trello, Notion, Agile/Scrum Why clients work with me: - I take ownership of existing systems and improve them, not just add features - I’ve been refactoring and stabilizing legacy frontend codebases since 2015 - I communicate clearly with founders, designers, and engineers - I focus on maintainability, performance, and long-term scalability I’m flexible with time zones, comfortable working with distributed teams, and happy to take responsibility beyond my immediate scope — especially in startup environments where impact and adaptability matter.


💡 Do you need someone that will fully understand your task and recommend optimal approaches to solve your PHP and MySQL issues quickly? 📚 Hire me and you will get over 20 years of knowledge in web application design and programming. 💾 I am highly experienced in Modern PHP 8, HTML5, CSS3 and native JavaScript. I’ve also been around long enough to have a lot of experience dealing with legacy code. 🌎 I am fluent in English and Spanish, with an extensive background working for clients in both languages worldwide. 👋🏻 I look forward to working with you on your next project, whatever the size.