Hire the Best React.js Developers in California

📣 FREE technical consultation (details below) 🐻 Proud UC Berkeley graduate (Applied Mathematics & Economics) and an entrepreneurial, reliable full-stack software developer with broad expertise across modern technologies (listed below). 💪💪💪 With experience as: • Full-Stack Team Lead at Camping World, a publicly traded company • Lead Technical Teaching Assistant at Hack Reactor, a leading software engineering bootcamp • Founder of Atini Studio, a high-performance software development agency With years of experience working with clients and leading engineering teams, I prioritize accountability, clear communication, and efficient execution. 🌈🌈🌈 I’m the founder of Atini Studio, a vibrant software development agency and a team I like to call software doctors: highly skilled engineers and creative UI/UX designers who diagnose, fix, and elevate digital products. ⌨️⌨️⌨️ What I help clients with: 📌 MVP development for startups 📌 Full-stack web applications 📌 Cross-platform mobile apps 📌 AI-powered features & integrations 📌 Clean implementation from Figma to production 📌 API integrations (Stripe, OpenAI, Google, Zoom, etc.) 📌 Performance optimization 📌 Technical architecture planning 📌 Product roadmap & scaling strategy We also leverage AI internally to accelerate development workflows and improve efficiency, so you get faster delivery without sacrificing quality. 🧩 Complimentary Technical Consultation Not sure how to move forward with your product? I can help you clarify: • The right tech stack • MVP scope • Timeline and budget expectations • System architecture decisions • Whether your current product is built correctly I offer a complimentary strategy session to help you create a clear and practical execution plan. 💻 Tech Stack: • Front End JavaScript | TypeScript | React | Next.js | React-Native | Angular | Vue.js | Tailwind CSS • Back End Node.js | NestJS | Python | Django | PostgreSQL | MongoDB | MySQL | ORM | GraphQL • API Integrations ChatGPT / OpenAI | Stripe | Google | Zoom | and more... • DevOps Amazon Web Services (AWS) | Firebase/GCP(Google Cloud Platform) | Azure | Docker • Testing Jest | Mocha | TDD • Developer Tools Git | npm | Webpack | Babel | Agile Methodology | Nginx • Design Adobe XD | Figma

Full-stack and React Native developer who builds web and cross-platform mobile apps, React, Next.js, Node.js, MongoDB · 5-star rated. Need one developer who can build your web app and mobile app without switching teams or losing context? I deliver complete, production-ready products across web and mobile — using React, Next.js, Node.js, MongoDB, and React Native for iOS & Android. Whether it's a SaaS web platform, a cross-platform mobile app, or both running off the same backend — I've got the full stack covered. What I build: ✅ Full-Stack Web Apps — React / Next.js + Node.js / Express backend ✅ Cross-Platform Mobile Apps — React Native (iOS & Android) ✅ REST API & GraphQL API — shared backend for web + mobile ✅ MongoDB & PostgreSQL Database Design ✅ Authentication — JWT, OAuth 2.0, NextAuth.js, Firebase Auth ✅ SaaS Dashboards, Admin Panels & Client Portals ✅ Push Notifications, Offline Support & App Store Deployment ✅ Responsive UI — Tailwind CSS, Material UI, Shadcn How I work: Clear communication, realistic timelines, and clean code your team can build on. You'll always know where the project stands — no surprises at delivery. Tech stack: JavaScript · TypeScript · React.js · Next.js · React Native · Node.js · Express.js · MongoDB · PostgreSQL · REST API · GraphQL · Firebase · Tailwind CSS · Expo · Git · Vercel · AWS Building a web platform, mobile app, or both? Send me your project brief and I'll respond promptly.

🚀 𝐈𝐍𝐕𝐈𝐓𝐄 𝐓𝐎 𝐈𝐍𝐓𝐄𝐑𝐕𝐈𝐄𝐖 𝐅𝐎𝐑 𝐀 𝐐𝐔𝐈𝐂𝐊 𝐂𝐎𝐍𝐒𝐔𝐋𝐓𝐀𝐓𝐈𝐎𝐍 💼 Delivered 100+ 𝐅𝐮𝐥𝐥-𝐒𝐭𝐚𝐜𝐤 𝐰𝐞𝐛 𝐚𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬 and 𝐌𝐕𝐏 𝐒𝐚𝐚𝐒-𝐟𝐨𝐜𝐮𝐬𝐞𝐝 𝐩𝐫𝐨𝐣𝐞𝐜𝐭𝐬 that helped startups and businesses generate $100k+ in revenue while reducing development time and saving founders dozens of hours through scalable, production-ready systems ⭐️ 𝐏𝐫𝐨𝐯𝐞𝐧 𝐑𝐞𝐬𝐮𝐥𝐭𝐬 & 𝐈𝐦𝐩𝐚𝐜𝐭 • Built and launched SaaS MVPs and Full-stack web applications used by real users • Helped founders move from idea → MVP → production faster with clean, scalable architecture • Helped startups launch MVPs faster with production-ready UI systems • Improved application performance, reliability, and user experience • Delivered systems that support real business workflows, users, and growth 💡 I’m not just a developer; I help businesses turn ideas into working full-stack web applications and SaaS products that can launch fast, scale efficiently, generate real value, and compete in real markets. 👨‍💻 𝐀𝐁𝐎𝐔𝐓 I specialize in full-stack development and SaaS MVP development, helping startups and founders build scalable web applications from scratch. 𝐌𝐲 𝐟𝐨𝐜𝐮𝐬 𝐢𝐬 𝐨𝐧: • Building SaaS MVPs fast without sacrificing quality • Building Full-stack Web applications fast without sacrificing quality • Fixing and improving broken Full-stack Web applications • Turning early-stage ideas into production-ready SaaS products I work closely with founders, teams, and designers to transform ideas into clean, maintainable full-stack applications, ensuring your product is not just built, but built to scale and last. ⚡ 𝐅𝐫𝐨𝐦 𝐢𝐝𝐞𝐚 𝐭𝐨 𝐞𝐱𝐞𝐜𝐮𝐭𝐢𝐨𝐧: Idea → MVP → Production → Scale 🛠 𝐖𝐇𝐀𝐓 𝐈 𝐁𝐔𝐈𝐋𝐃 • SaaS platforms and MVPs • Full-stack web applications and tools • Dashboards, admin panels, and internal systems • Subscription-based platforms (Stripe billing systems) • API-driven web applications and integrations • Startup products from concept to launch ⚙️ 𝐂𝐎𝐑𝐄 𝐒𝐓𝐀𝐂𝐊 🎨 𝐅𝐫𝐨𝐧𝐭𝐞𝐧𝐝: React, Next.js, JavaScript, TypeScript, HTML, CSS, Tailwind CSS, Material UI, Framer Motion, GSAP. 🧠 𝐁𝐚𝐜𝐤𝐞𝐧𝐝: Node.js, Express, Nest.js, REST APIs, GraphQL, Convex, API Architecture. 📱 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞: PostgreSQL, MongoDB, Supabase, Firebase. ☁️ 𝐃𝐞𝐩𝐥𝐨𝐲𝐦𝐞𝐧𝐭: Vercel, Netlify, Render, AWS, DigitalOcean, Cloudflare 🔗 𝐈𝐧𝐭𝐞𝐠𝐫𝐚𝐭𝐢𝐨𝐧𝐬: Stripe, PayPal, OpenAI, Figma to React 🏆 𝐑𝐄𝐂𝐄𝐍𝐓 𝐑𝐄𝐒𝐔𝐋𝐓𝐒 • Built SaaS MVPs used by startups and growing businesses • Helped founders launch products faster with scalable architecture • Delivered production-ready full-stack applications with clean, efficient code • Improved full-stack web application's performance, structure, and long-term maintainability 🚀 𝐒𝐄𝐑𝐕𝐈𝐂𝐄𝐒 • SaaS MVP development (end-to-end) • Full-stack web application development • API development and third-party integrations • Fixing and improving existing SaaS or Full-stack web applications 🤝 𝐖𝐇𝐘 𝐂𝐋𝐈𝐄𝐍𝐓𝐒 𝐖𝐎𝐑𝐊 𝐖𝐈𝐓𝐇 𝐌𝐄 • Product-focused mindset (I think beyond just code) • Clean, scalable, production-ready architecture • Strong understanding of SaaS systems and MVP development • Clear communication and reliable delivery • Ability to take projects from idea to launch and beyond I don’t just build features or web applications; I help you build a product that works, scales, and grows. 📩 𝐋𝐄𝐓'𝐒 𝐁𝐔𝐈𝐋𝐃 𝐘𝐎𝐔𝐑 𝐏𝐑𝐎𝐉𝐄𝐂𝐓 If you need a developer to build your SaaS MVP or full-stack web application or launch your product, click "Invite to Job" and let’s get started. 🔑 𝐊𝐄𝐘𝐖𝐎𝐑𝐃𝐒 Full-stack developer, SaaS, MVP, Web application, Website development, Web app development, SaaS development, MVP development, SaaS MVP, SaaS developer, Build website, Custom website, Full stack website, Startup MVP, Build SaaS product, Launch MVP, Web platform, Business website, Web application development, AI development, JavaScript, Typescript, TML5, React, Node.js, API, API Interation, Supabase, MongoDB, Typescript, CSS, HTML, PostgreSQL programming, Web Development, Nestjs, Vercel, Github, Full-Stack development, Payment Gateway Integration, Tailwind CSS, SaaS Software developer, Backend developer, Frontend developer, Web developer, Full stack, React developer, Node.js developer, MERN stack developer, Laravel developer, JavaScript, TypeScript, React, React JS, Next.js, Node.js, API, API integration, API development, Database development, MongoDB, PostgreSQL, Supabase, Database architecture, Database development, Cloud deployment, Vercel, GitHub, Stripe integration, Payment gateway integration, SaaS web app, SaaS dashboard, Subscription system, User authentication, Role-based access, Fix web app, Deploy web app, Rebuild website, Responsive website, Scalable web app, High-performance web app, Dashboard development, Admin panel, Full Stack Developer, SaaS Developer, SaaS MVP, MVP Development, Web Application

🚀 𝐅𝐮𝐥𝐥 𝐒𝐭𝐚𝐜𝐤 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐫 | 𝟏𝟎+ 𝐘𝐞𝐚𝐫𝐬 𝐨𝐟 𝐄𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐞 | 𝟑𝟎+ 𝐒𝐮𝐜𝐜𝐞𝐬𝐬𝐟𝐮𝐥 𝐏𝐫𝐨𝐣𝐞𝐜𝐭𝐬 I don’t just write code – 𝐈 𝐬𝐨𝐥𝐯𝐞 𝐩𝐫𝐨𝐛𝐥𝐞𝐦𝐬, 𝐨𝐩𝐭𝐢𝐦𝐢𝐳𝐞 𝐩𝐞𝐫𝐟𝐨𝐫𝐦𝐚𝐧𝐜𝐞, 𝐚𝐧𝐝 𝐞𝐧𝐬𝐮𝐫𝐞 𝐞𝐯𝐞𝐫𝐲𝐭𝐡𝐢𝐧𝐠 𝐰𝐨𝐫𝐤𝐬 𝐟𝐥𝐚𝐰𝐥𝐞𝐬𝐬𝐥𝐲. I thrive on challenges and enjoy building apps that are not only powerful but also intuitive and fun to use. Let’s create something outstanding together! To kick things off, I offer a 𝐅𝐑𝐄𝐄 𝟒𝟎-𝐦𝐢𝐧𝐮𝐭𝐞 𝐭𝐞𝐜𝐡 𝐜𝐨𝐧𝐬𝐮𝐥𝐭𝐚𝐭𝐢𝐨𝐧 where we can explore your project goals and define the best path forward. ✅ 𝐁𝐚𝐜𝐤𝐞𝐧𝐝: ◈ PHP: Laravel, Yii2, Symfony, Zend, CakePHP, CodeIgniter ◈ Node.js: Express, Nest.js ◈ Python: Django ◈ Databases: MySQL, PostgreSQL, DynamoDB, MongoDB ◈ API Development: REST, GraphQL, WebSockets ◈ Cloud: AWS, Google Cloud, Azure, Docker ✅ 𝐅𝐫𝐨𝐧𝐭𝐞𝐧𝐝: ◈ JavaScript: React.js, Next.js, Nuxt.js, Vue.js, Angular.js ◈ TypeScript, UI Libraries: Redux, Material UI, Bootstrap, Tailwind ✅ 𝐅𝐮𝐥𝐥 𝐒𝐭𝐚𝐜𝐤: ◈ Web3 and OpenAI integrations ◈ API & Payment Gateway integrations ✅ 𝐂𝐌𝐒 & 𝐏𝐖𝐀: ◈ WordPress: Custom themes & plugins, Elementor ◈ Progressive Web App (PWA) development ✅ 𝐃𝐞𝐬𝐤𝐭𝐨𝐩: ◈ Python, JavaScript/TypeScript 𝐑𝐞𝐜𝐞𝐧𝐭 𝐏𝐫𝐨𝐣𝐞𝐜𝐭𝐬: ➤ PuzzleTrip – Aggregator for rental and tour services (cars, yachts, custom trips) ➤ Grand Time – Web3 platform connecting businesses and freelancers globally ➤ ArmRoom – Dating app for connecting people across cultures I'm here to help tackle technical challenges and build reliable, high-impact digital products. Let’s make it happen!

✨ Senior API Integration & AI Automation Specialist | LLM & OpenAI Expert ✨ Core Expertise: API Integrations • AI Agents • LLM Applications • OpenAI API • Payment Gateways • ERP Systems • Chatbots • Microservices • Marketing Tools • Healthcare Systems • Financial Platforms • Middleware • CRM • Social Media APIs • Databases • E-commerce • Workflow Automation • HubSpot • Salesforce • QuickBooks API • NetSuite Integration • Odoo ERP Development • Zoho Books API I help businesses connect platforms, automate workflows, and build scalable AI-powered systems using APIs, LLMs, and modern backend technologies. My expertise includes API integrations, AI agents, OpenAI-powered applications, payment gateway systems, CRM/ERP synchronization, workflow automation, and custom middleware development. I focus on building reliable integrations that improve operational efficiency, reduce manual work, and scale smoothly with business growth. Core Expertise: ✔ API Integrations ✔ AI Agents & LLM Applications ✔ OpenAI API & Automation ✔ Payment Gateway Integrations ✔ QuickBooks & Xero Integrations ✔ CRM & ERP Systems ✔ Twilio, WhatsApp & Messaging APIs ✔ Webhooks & Microservices ✔ Healthcare & Financial Systems ✔ E-commerce Integrations ✔ Custom Backend Development Tech Stack: Node.js • NestJS • Python • FastAPI • Express.js • PostgreSQL • MongoDB • Redis • REST APIs • GraphQL • Docker • AWS • Firebase I’ve worked on integrations involving payment platforms, accounting systems, AI chatbots, communication APIs, SaaS products, and enterprise workflow automation systems. Why clients work with me: ✅ Clean and scalable architecture ✅ Fast communication and reliable delivery ✅ Business-focused solutions ✅ Long-term maintainable systems ✅ Strong debugging and problem-solving skills If you need an experienced developer to build secure integrations or AI-powered automation systems, feel free to invite me to your project or schedule a quick chat. Full Stack Developer | MERN Stack Developer | Base44 Developer| React.js Developer | Next.js Developer | Node.js Developer | JavaScript Developer | Web Application Development | Custom Web Applications | SaaS Development | MVP Development | Startup Developer | Scalable Web Applications | Backend Developer | Frontend Developer | API Integration | REST API Development | GraphQL API | API Developer | Third-Party Integrations | Payment Gateway Integration | Stripe | PayPal | CRM Integration | HubSpot | Zoho| Salesforce | Dashboard Development | Admin Panel Development | Automation Developer | Workflow Automation | Zapier | Make | Integromat | n8n | Database Design | MongoDB | PostgreSQL | MySQL | Firebase | Supabase | Redis | Real-Time Applications | Web Performance Optimization | Responsive Web Design | Tailwind CSS | Modern UI/UX | Cloud Deployment | AWS | Vercel | Docker | CI/CD Pipelines | GitHub Actions | Serverless Architecture | Microservices Architecture | Secure Authentication | JWT | OAuth) | Role-Based Access Control | RBAC | SaaS Platforms | Marketplace Development | Booking Systems | ERP Systems | CRM Systems | Scalable Backend Systems | Twilio API | WhatsApp API | SMS API | Messaging API | VOIP Systems | Cloud Telephony | Call Automation | Auto Dialer Systems | IVR Systems | Call Routing | WebRTC | SIP Integration | Call Recording & Analytics | CRM Calling Integration | QuickBooks Online Integration | QBO Automation | Accounting Workflow Automation | Financial Data Sync | Invoicing & Payments Sync | Expense & Transaction Automation | Bookkeeping Integrations | POS to QuickBooks Sync | Payroll & Reporting Automation | NetSuite Integration | Odoo ERP Development | Zoho Books API Integration | ERP & Accounting Software Integrations

I take SaaS products to production. Solo or with your team. Backend, frontend, payments, AI, infrastructure. Most of my work is with founders who need their product built right, or teams that need a senior dev who can own a piece of the codebase without hand holding. Tech I use: - TypeScript, Next.js, React - Python, Django, NestJS - PostgreSQL, AWS, Docker - Stripe, OpenAI, Claude