Hire the Best Auth0 Developers

Top-rated Full-Stack Developer with 12+ years delivering secure, scalable solutions that produce measurable business outcomes for global clients. What clients achieved with my work Reduced login friction and support costs by up to 80% after SSO rollouts (SAML, OAuth2, OIDC), improving user adoption and lowering helpdesk tickets. Cut user onboarding time from days to minutes via centralized identity flows and automated provisioning. Increased team productivity up to 40% with custom Office and Google Workspace add-ins that automate repetitive work and integrate third-party systems. Strengthened security and compliance (SOC2, ISO, GDPR) by implementing hardened IAM, PKI, and cryptographic document signing. Scaled multi-tenant SaaS to thousands of organizations with sub-second auth latency and 99.9% uptime. Accelerated go-to-market and recurring revenue growth by delivering modular auth and API platforms. Selected results & experience 100+ SSO integrations across Okta, Auth0, Azure AD/Entra ID, Google Workspace, AWS Cognito, Ping Identity, ADFS, Salesforce. Architected a multi-tenant Identity Broker (sso.id) enabling customers to connect multiple identity providers in minutes, boosting partner integrations and conversions. Built 15+ Office & Google Workspace add-ins (Word, Excel, Outlook, PowerPoint, Gmail, Sheets, Docs), saving teams hundreds of person-hours per month. Developed 20+ SaaS platforms from MVP to enterprise scale with AI automation and APIs (YouTube, AWS, Firebase, Microsoft Graph), improving engagement and monetization. Implemented PKI, PDF signing, and blockchain anchoring to reduce fraud risk and streamline audits. Technical stack Protocols: SAML, OAuth2, OpenID Connect, SCIM, JWT Platforms: Okta, Auth0, Azure AD/Entra ID, Google Workspace, AWS Cognito, Ping Identity, ADFS, Salesforce Frontend: React, Next.js, Vue, Angular, TypeScript Backend: .NET 8 / C#, Node.js, Python, PHP (Laravel, Django) Databases: MySQL, Oracle, MongoDB Specialized: PKI, cryptography, PDF signing, blockchain-secured documents Why hire me ROI-focused: $1.2M+ earned across 200+ projects with measurable improvements in security, productivity, and time-to-market. Business-first engineering: I reduce operational costs, accelerate onboarding, and unlock new revenue channels. Long-term partner: responsive, reliable, and focused on evolving systems as your business grows. Tell me about your auth, add-in, or SaaS challenge and I’ll outline how we can reduce risk, save time, and increase adoption.

Dear client! My name is Lex, I am am AWS Engineer. Let me ask you: did you have it all on Upwork? Contractors who go offline for days without notice? Freelancers ruined your production environments? Agencies knowing what you need better than you? Indian folks who don't have a clue about a single thing written on their profiles? My morals are different. ⭐️ I am always on for you. My response SLA is minutes. Not hours. Not days. Minutes. ⭐️ My consulting style is gentle and non-invasive. You always have the final say. ⭐️ I am a narrow specialist: AWS is the only thing I sell here, but be certain that I am the best in my league. This is some of things I enjoy: ✅ Web and mobile cloud-native microservice and serverless architectures (AWS) ✅ Cloud solutions cost reduction ✅ External API providers and COTS systems integration using Apache Camel and n8n ✅ Data pipelines, ETLs, ELTs ✅ Bespoke technology assessments ✅ Fully autonomous AI agents My Technology Background ✅ Industry-standard enterprise Java stack: Spring Boot, Hibernate, Apache Camel ✅ Experience with Apache Kafka, ElasticSearch, Redis ✅ Exposure to front-end stack and paradigms: Angular, React, micro-frontends, SPAs ✅ Data stores: PostgreSQL, MySQL, MongoDB ✅ Cloud providers: Amazon Web Services ✅ Standards and protocols: OpenAPI, REST, Json RPC, GraphQL, Mambu, n8n

Full Stack AI Developer | AI MVP Expert in Claude Code, Lovable, Base44, Replit, Bolt & v0 I turn AI-built ideas into production ready apps that ship, scale, and get paid. Most founders don't need another developer. They need someone who can take an idea or a half working AI build and turn it into a real product before time and budget run out. That's exactly what I do. I'm a Full Stack AI Developer and AI MVP expert specializing in the modern vibe coding stack: Claude Code, Lovable, Base44, Replit, Bolt, v0, and Cursor, backed by React, Next.js, TypeScript, Node.js, Supabase, and Stripe. I take what these AI tools start and make it actually work stable, scalable, and ready for real users and real payments. Founders, startups, and agencies usually come to me in one of two situations: YOU HAVE AN IDEA AND NEED IT BUILT FAST I take you from concept to a launched MVP authentication, database, payments, and a clean, responsive UI using React, Next.js, TypeScript, Node.js, Tailwind CSS, and Supabase, with Stripe wired in so you can charge from day one. I build full stack web applications, SaaS platforms, AI apps, AI agents, and mobile apps (iOS and Android) that go live with little technical burden left on you OAuth, Stripe, environment keys, and third party integrations handled properly. YOU HAVE AN AI GENERATED APP THAT LOOKS GREAT BUT BREAKS Vibe coded apps built in Base44, Lovable, Replit, or Bolt often look impressive but fall apart on bugs, broken integrations, failed deployments, and code that won't scale. I specialize in inheriting and stabilizing existing builds auditing the architecture, finding the root cause, fixing it cleanly, and deploying to web or the App Store. If fixing one bug keeps triggering three more, that's exactly the kind of unstable build I stabilize and launch. WHAT I BUILD AND FIX AI MVP development, SaaS development, and AI app development AI agent development and automation (Claude API, OpenAI, Makecom, n8n, Zapier) Vibe coding cleanup, bug fixing, and debugging (Base44, Lovable, Replit, Bolt, v0, Cursor) Base44 app audits, feature expansion, and stabilization of complex existing builds Base44 to Supabase migration stripping proprietary wrappers, rebuilding auth, RLS, PostgreSQL Payment and subscription integration (Stripe, PayPal) Database and backend (Supabase, PostgreSQL, MongoDB, Redis, Firebase) API integration and webhooks (REST APIs, OAuth 2.0, third party tools) Voice AI and conversational AI (Twilio, OpenAI Realtime API, Retell.ai, Vapi) Mobile deployment Capacitor wrapping, push notifications, App Store and Play Store submission Workflow automation and internal dashboards (n8n, Make com, Airtable) Cloud deployment and CI/CD (AWS, Vercel, Railway, Netlify) A FEW EXAMPLES OF RECENT WORK Integrated Stripe subscriptions and handled full deployment for a Lovable SaaS app Fixed and shipped a Base44 meal planner app through API integration and targeted bug fixes Resolved a broken Replit build and managed full App Store submission Diagnosed and repaired an AI agent's architecture with clear root cause analysis In plain terms: I help founders, startups, and agencies turn AI built ideas into real, paying products using Claude Code, Lovable, Base44, Replit, and a modern full stack toolkit. WHY CLIENTS KEEP WORKING WITH ME Unlike developers who only write code, I focus on the whole product journey UX, architecture, scalability, payments, and long term growth. I've built AI-powered SaaS products, AI agents, voice receptionist and lead management platforms, automation systems, internal dashboards, and marketplace MVPs that solve real operational problems. What working with me looks like: Fast, proactive communication I don't go quiet mid project A visible win early, so you feel real progress in week one Clean, documented, maintainable code your team can build on Honest scoping I'll tell you upfront what it takes to ship My clients consistently highlight clear communication, quality, reliability, and ownership of outcomes and my reviews reflect that. WHO I WORK BEST WITH Startup founders launching a first AI MVP, agencies needing a reliable build or rescue partner, and growing businesses adding AI features, automation, or payments to an existing product whether you're starting from a blank canvas or a broken vibe coded build. HOW I WORK Discovery call → clear scope and timeline in plain language → focused milestones with an early win shipped fast and steady updates → thorough testing, clean deployment to web or App Store, and documentation your team can run with. LET'S TALK If you're building an AI MVP, fixing a Base44, Lovable, or Replit app, migrating off a platform, integrating Stripe, deploying AI agents, or modernizing an existing product send me a message with what you're working on and where it's stuck. I'll reply quickly and tell you honestly what it will take to ship it. Ready to turn your idea or your half finished build into a product people pay for?

Senior Full-Stack Developer | React, Next.js, React Native | AI & SaaS Expert I help startups and founders build scalable web and mobile products that are secure, maintainable, and ready for real-world growth. With 10+ years of experience, I specialize in taking products from idea to production. I have delivered SaaS platforms, AI-powered applications, healthcare systems, fintech products, and enterprise solutions used by thousands of users worldwide. What I Bring to Your Project Full-Stack Expertise: End-to-end development from frontend (React, Next.js) to backend (Node.js, AWS) and mobile (React Native). AI Integration: Building AI agents, RAG systems, and automation workflows using OpenAI, Claude, and Base44. Scalable Architecture: Clean code, reliable delivery, and long-term technical ownership. Industry Experience: Healthcare, FinTech, Marketplaces, Delivery, Gaming, and Social Platforms. Core Tech Stack Frontend: React.js, Next.js, Vue.js, Angular, TypeScript, Tailwind CSS Mobile: React Native, Expo, iOS & Android Deployment Backend: Node.js, Express, Firebase, Supabase, PostgreSQL, MongoDB, AWS Payments & APIs: Stripe, RevenueCat, GraphQL, REST APIs, Webhooks Selected Projects TradeBulls: Trading platform supporting equities, derivatives, and commodities. Vuukle: Community platform serving millions of users globally. Store To Door: Same-day delivery platform with driver and dispatch workflows. iPass: Identity verification solution with OCR and liveness detection. Why Clients Work With Me - 10+ Years of Professional Experience - Production-Ready, Maintainable Code - Clear Communication & Reliable Delivery - Comfortable Taking Ownership of Existing Codebases - Long-Term Partnership Mindset Whether you need an MVP, AI-powered SaaS platform, or an experienced engineer to improve an existing product, I can help deliver a scalable solution that supports your business goals.

I ship production-ready React Native apps to the App Store and Play Store — not demos that break after launch. 5+ years building cross-platform mobile apps (React Native, Expo, TypeScript) for startups and product teams in the US, UK, and EU — from MVP to live users, payments, and real-time features. Hi, I'm 𝙂𝙝𝙪𝙡𝙖𝙢 𝘿𝙖𝙨𝙩𝙖𝙜𝙞𝙧 — a React Native and Expo developer focused on iOS and Android apps that perform well in production, scale cleanly, and ship on time. What I do best: • React Native (CLI + Expo) — cross-platform iOS and Android development • App Store and Play Store publishing — TestFlight, EAS, production releases • Backend integration — NodeJS, Express, NestJS, REST and GraphQL APIs • Authentication — Firebase, Supabase, JWT, OAuth, Apple and Google Sign-In • Payments — Stripe, RevenueCat, Apple IAP, Google Pay • Real-time features — WebSockets, live updates, push notifications, deep linking • AI integration — OpenAI API, chatbots, smart automation • Performance — optimization, bug fixing, legacy app rescue • Web when needed — NextJS, React, ThreeJS, Tailwind, Supabase Recent projects: • Sol Hour — Real-time interactive DJ platform with 3D avatar and live guest sessions • Fenzro — AI-powered business management mobile app (React Native + Expo) • JUVA OS — Multi-service business mobile app with Expo, EAS builds, and TestFlight deployment • Juice Ordering Platform — Restaurant and F&B ordering app with cart, checkout, and order tracking • Inventory Management App — Stock, sales orders, and invoicing for retail businesses • Dex Remit — International money transfer fintech app with Stripe payments • CrowdCare Aid — Crowdfunding app with donation and payment flows • Compaklink and DiveIn — Social networking and messaging with real-time chat • Movie Streaming App — Custom video player with offline downloads • E-Commerce and Booking Apps — Product catalog, orders, and calendar scheduling Why clients work with me: ✓ 100% Job Success Score ✓ Clear communication — daily updates, fast response (0–4 hours) ✓ Clean, maintainable code your team can extend ✓ I work independently or with your existing dev team ✓ Available 30+ hrs per week — open to contract-to-hire If you need a reliable React Native developer who can take your app from idea to MVP to App Store launch, I would love to help. Message me with your project details and I will reply with a clear plan. ━━━━━━━━━━━━━━━━━━━━━━━━━━━ Keywords ━━━━━━━━━━━━━━━━━━━━━━━━━━━ React Native Developer | React Native Expo | iOS Developer | Android Developer | Mobile App Developer | Cross-Platform Developer | TypeScript | JavaScript | NodeJS | Express | MongoDB | Firebase | Supabase | Stripe | RevenueCat | OpenAI API | REST API | GraphQL | ThreeJS | React Three Fiber | NextJS | MVP Developer | Startup App Developer | App Store Deployment | Performance Optimization

✅ I HELP SOLVE YOUR TECH PROBLEMS, SIMPLE AS THAT. ✅ I'LL LEVERAGE MY DECADES OF EXPERIENCE AS A FULL-STACK WEB DEVELOPER / SYSTEMS ARCHITECT / TECHNICAL LEAD / TECH MANAGER / FRACTIONAL CTO – WITH TOP COMPANIES – to get your project done correctly and cost effectively, using a problem-solving approach honed over decades of experience in the industry, capped off with excellent communication skills. ✅ IF YOU NEED AN ENTIRE TECH TEAM ASSEMBLED, LARGE OR SMALL... – If, instead of my individual services, you’re looking for a team to be built out to work on your project, I will use my many years of tech management experience to assemble and personally manage that team, ensuring the highest quality of delivered work, following industry best practices, and engaging my personal philosophy of software development that I have fine-tuned over my decades-long career. ————————————————————————— MY NAME IS MICHAEL R. KLOSNER, AND I'M HERE TO HELP YOU: ➠ OVER 15 YEARS EXPERIENCE IN THE INDUSTRY ➠ UPWORK EXPERT-VETTED (TOP 1% FREELANCER) STATUS ➠ 100% 5-STAR REVIEWS FROM ALL MY CLIENTS. ✅ I’VE DEVELOPED / MANAGED FOR WORLD-FAMOUS COMPANIES / ORGANIZATIONS JPMorgan • March of Dimes • MultiView • Cartier • SEI • Festo • More... ✅ I’M A TOP 1% RATED FREELANCER, EXPERT-VETTED BY UPWORK The Upwork Expert-Vetted program identifies the top 1% of talent on the platform. All Expert-Vetted freelancers undergo a rigorous screening process. ✅ I HAVE A 100% 5-STAR RATING ⭐⭐⭐⭐⭐ 100% satisfaction and 5-Star ratings from every single one of my Upwork clients, who trust me with their most sensitive software products and executive-level decision making for their companies. ✅ HERE'S WHAT A RECENT MAJOR UPWORK CLIENT HAD TO SAY "Working with Michael was a seamless experience. He is highly skilled, timely, and brings a great deal of technical talent to the table. What stood out most was his ability to provide practical advice that saved us time and resources. He navigated every challenge we threw at him with a 'problem-solver' mindset. I will definitely be hiring him again for future software needs!" ✅ YALE-EDUCATED COMPUTER SCIENTIST I hold a B.Sc. in Computer Science from Yale University and an M.Sc. in Marine Biology from the University of the Algarve in Faro, Portugal. I have studied directly under leading experts in Computer Science, including winners of the Turing Award, the highest distinction in the field. ✅ EXCELLENT COMMUNICATOR Top clients specifically choose to work with me because they value the clear and concise communication that I provide throughout the entire lifecycle of the project. Whether with my clients themselves, with senior or junior developers, non-technical staff, investors or potential customers, I have a proven track record of excellent written and spoken communication skills, both with individuals and small or large groups. ✅ LET’S GET YOUR PROJECT DONE THE RIGHT WAY! Take a moment to text me with answers to the following 3 questions, and I’ll get back to you, within 24 hours, with a detailed response: 1. What is the nature (scope) of your project and what is the ultimate goal of your business / organization? 2. What is the single major technological block you are facing right now that prevents you from completing the project? 3. If you could have your project done the right way, what exactly would that look like to you? ————————————————————————— MICHAEL R. KLOSNER ➠ Upwork Expert-Vetted / 100% Client Satisfaction ➠ Full Stack Developer ➠ Systems Architect ➠ Tech Manager ➠ Fractional CTO ➠ 15+ Years Experience SELECTED TECHNICAL EXPERTISE ➠ Technology Management, CTO, VP Engineering, Lead Developer ➠ NET Core (7,8,9) / .NET Framework, MVC, C#, C++, C ➠ JavaScript, React.js, Node.js, Express.js, jQuery, TypeScript, Angular, Wix Blocks (Velo) ➠ SQL, SQL Server, MySQL, Stored Procedures, NoSQL (MongoDB), Entity Framework ➠ eCommerce Integration, Stripe, Amazon Payments, PayPal, Shopify ➠ SSO, OAuth, Okta, OpenID Connect (OIDC), JWT, 2FA ➠ DevOps, Azure Cloud, AWS (EC2, RDS, EBS), SDLC, Git, Atlassian ➠ HTML 5, CSS 2/3, XML, XSLT, JSON, AJAX / Fetch / Axios ➠ REST API, Web API, Zapier, Webhooks, ActiveCampaign, SendGrid, Lucene / SOLR, WordPress, PHP, Java ➠ Agile, Scrum, Clean / SOLID Architectures, Headless Stack / CMS ➠ Systems Architecture, Mathematics, Matlab, Signal processing, R (Statistics) / RStudio