As a senior software engineer and architect, I have over 25 years experience partnering with businesses to transform their ideas into functional software products. I excel at software engineering, software architecture design and planning, leading development teams, writing technical specifications, and designing user interfaces and experiences. My work spans development of both enterprise and consumer applications with a focus on artificial intelligence, e-commerce and online payments, iOS and Android applications, API integrations, hardware integrations, server administration, automations, content management, web development, and SEO - all with an emphasis on exceptional design. I understand the importance of striking a balance between timeline, budget and feature set when designing and phasing a project, ensuring it works realistically within a business’ constraints. My communication style is clear, concise and transparent. When you hire me, you gain a team player that takes full ownership of his assignments and is guided by a relentless work ethic. I am proactive in looking ahead for potential issues and opportunities, and provide these insights as continuous feedback to stakeholders. While I am eager to discuss projects both large and small, simple and complex, covering a wide range of disciplines, below is a list of areas where I have deep expertise: Artificial Intelligence Extensive experience implementing AI technologies, including custom AI agents, conversational chatbots, recommendation engines, automated decision-making, predictive analytics, personalized user interactions, and content analysis/generation. Skilled in prompt engineering, model fine-tuning, and building hybrid systems combining multiple AI models with traditional software components. Proficient in integrating frontier models from OpenAI, Anthropic, Google, and Meta. I maintain expert knowledge of current and forthcoming offerings, enabling me to guide clients in selecting services that deliver optimal output at economical costs. API Integration Deep expertise building secure, efficient, and well-documented API integrations, including RESTful, GraphQL, legacy services (SOAP, XML-RPC), OAuth and other authentication protocols, and real-time data synchronization. My integration experience includes: Stripe, Plaid, Square, Twilio, SendGrid, Slack, Google/Bing/Meta Ads, Salesforce, HubSpot, Pipedrive, Google Docs/Sheets/Drive, Klaviyo, Mailchimp, Hootsuite, Monday.com, Quickbase, Teamwork, Asana, Quickbooks, NetSuite, Zendesk, Freshdesk, Intercom, DocuSign, Google Analytics, Mixpanel, Segment, Google Maps, Mapbox, and more. DevOps and Server Administration Twenty years experience in setup, migration, and maintenance of Unix/Linux hosting environments, including 15 years managing AWS infrastructure as well as Azure, Google Cloud, Heroku, Cloudflare, and others. Skilled in optimizing performance, ensuring availability, load balancing, security hardening, automated deployments, monitoring and alerting systems, and maintenance automation. Thrives during emergency situations and catastrophic failures under extreme pressure. E-commerce I’ve developed custom e-commerce offerings that have processed over a billion dollars in transactions. Functionality has included payment processing integrations, bi-directional third-party inventory management and POS integrations, fulfillment pipelines, subscription services, and high volume architectures processing thousands of orders per minute. Android & iOS Development Ten years of experience building native and non-native Android & iOS apps and supporting API suites with hundreds of App Store and Google Play submissions. Feature sets include e-commerce, push notifications, user authentication, location services, deep linking, barcode scanning, and Bluetooth low energy (BLE) beacons. Cannabis Tech Fourteen years experience developing software for cannabis dispensaries and MSOs, including online ordering, in-store kiosks, in-store TV menus, and Android/iOS apps. Expert knowledge integrating with cannabis POS platforms and APIs, including Dutchie POS (formerly LeafLogix) and Dutchie Plus, Jane POS and Jane Roots, Treez, BioTrack, Greenbits, Blaze, Flowhub and MJ Platform, as well as delivery logistics platforms like Onfleet and Detrack. Subject matter expert on Android and iOS apps for dispensaries, having submitted more dispensary apps than any other developer in the world. Fractional CTO & Consulting Apart from software development, I also offer fractional CTO services as well as consultation services to businesses during the idea conception, planning, and pre-production phases of their software projects. This can include product design, strategic planning, technical feasibility analysis, market research, risk assessment, budgeting and cost estimation, project scoping, workflow design, team structure and roles, RFP creation and management, and vendor selection and staffing.

I help startups and growing businesses stabilise, improve, and ship digital products — especially platforms built with AI tools, low-code workflows, and vibe-coded apps on platforms like Replit. If you have a product that was built fast and now needs to be fixed, cleaned up, extended, or made reliable for real users, that’s where I come in. I work with founders and teams to turn fragile MVPs into usable, scalable products by improving UX, fixing broken flows, refining the product strategy, and helping engineering move faster with less chaos. What I can help you with • Stabilising platforms built on Replit, AI app builders, low-code tools, and vibe-coded workflows • Improving broken or confusing user journeys • Turning rough prototypes into production-ready product experiences • Designing and shipping SaaS platforms, internal tools, dashboards, and client-facing apps • Adding AI features that are actually useful to users • Scoping MVPs, prioritising features, and reducing product risk • Leading product execution from idea to launch What clients hire me for • Platform rescue: fixing products that were built quickly but are now unstable, messy, or hard to maintain • UX + product improvement: making apps easier to use, clearer, and more likely to convert • Rapid prototyping: building and testing new features quickly before teams overinvest • AI workflow implementation: integrating OpenAI, automation tools, and smart product experiences into existing platforms • Founder support: helping non-technical or overstretched teams make better product decisions My approach I don’t just make screens look better or build random features. I help clients figure out what is breaking, what matters most, and what needs to happen next to make the product more reliable and more valuable. That might mean: • auditing the product and identifying friction points • redesigning key flows • improving onboarding and conversion • cleaning up the product structure • working with developers to implement better solutions • using tools like Replit, Figma, React, Laravel, Supabase, n8n, OpenAI, and payment integrations to move quickly Types of projects I’m a strong fit for • Startups with an MVP that feels unstable or unfinished • Founders who built fast with AI tools and now need product structure • Teams that need a UX/product partner who also understands implementation • Businesses adding AI features, automation, or new digital services • Companies that need someone to bridge strategy, design, and delivery If your app was built quickly and now needs to be stabilised, improved, or prepared for growth, I can help you get it there.

My name is Matthias, I'm a software developer with 10+ years of experience, and since 2019 I've focused on Python and AI. I build LLM apps, generative image tools, and the backends that run them. I've been working with Stable Diffusion since the day it launched, and I keep up with what's current. These days that means Flux.2 and Z-Image for image generation, GPT-5.5 and open models like Mistral for text. I've shipped real products with this stuff, not just demos. Some things I've built: a children's story generator that writes and illustrates stories, a tool that summarizes YouTube videos, an app that auto-illustrates articles, and a roleplay app for practicing social skills running on a fine-tuned Mistral model. Every one went from idea to live and deployed. What I'm good at is taking an AI model and turning it into something that actually works for users. GPT integration, a custom image pipeline, a fine-tuned model, or a full Python backend with the API and server setup behind it. I can also build the iOS or Mac app on top if you need it, since that's where I started. What I can build for you: - LLM apps and chatbots (GPT-5.5, Mistral, local models) - Image generation pipelines (Flux, Z-Image, Stable Diffusion, fine-tuning) - Python backends and APIs (FastAPI, Flask, Django) - Fine-tuning, RAG, and LangChain setups - Web scraping and data extraction - Deployment on Docker, Linux, AWS, GCP Core skills: - Languages: Python, JavaScript, Swift, Objective-C - AI/ML: GPT-5.5 API, Flux, Z-Image, Stable Diffusion, fine-tuning, LangChain, PyTorch - Backend: FastAPI, Flask, Django, PostgreSQL, Redis, Celery - Infra: Docker, Linux, AWS, GCP, Git, Nginx Why hire me: I finish what I start. Everything above is deployed and working. I've co-founded a few startups so I think about the product and the user, not just the code. And I'm easy to work with, I communicate clearly and hit deadlines. Let's talk about your project.

Hi, I'm Xiuny! I'm a senior Full-Stack Software Engineer with over 4 years of experience leading complex projects from concept to launch. Whether you're a startup needing a rapid prototype or an established business building a scalable, high-performance system, I can help. I am your all-in-one technical partner. My expertise covers the full development lifecycle: Core Expertise: Full-Stack Web, Mobile App (iOS/Android), and Game Development. Key Technologies: C++, Java, JavaScript, React.js, and Node.js. Game Engines: Expert in Unreal Engine 5 (Blueprints & C++). Full Project Management: I manage the entire process, from architecture and prototyping to deployment and optimization. Clear Communication: I am committed to your success and will keep you updated every step of the way. I'm precise, efficient, and bring creative solutions to every project. Let's build your next big idea together. Send me a message!

I help founders and business operators build, launch, take over, and scale business-critical mobile and web platforms. Most clients I work with are not just looking for “an app developer.” They usually have a real business workflow that needs to become software: customer portals, admin dashboards, booking systems, dispatch flows, marketplaces, SaaS products, AI-assisted tools, internal operations platforms, or existing products that need to be stabilized and improved. Across 100+ projects, I’ve helped companies turn complex product ideas and operational processes into reliable software used by real customers. The products I’ve worked on have supported 2M+ app downloads, large active user bases, revenue growth, and long-term business operations. HOW I CAN HELP 👉A single technical partner for the full product lifecycle I can support the full process: product planning, UX/UI design, mobile app development, web app development, backend development, REST API integrations, admin systems, QA, deployment, app store launch, and post-launch support. 👉Turning manual workflows into scalable platforms If your business currently depends on spreadsheets, emails, manual follow-ups, disconnected tools, or repetitive admin work, I can help turn that workflow into a structured product with clear roles, automation, notifications, reporting, and operational visibility. 👉Taking over and improving existing products If you already have a product but the codebase is messy, the previous developer disappeared, documentation is missing, or the app is hard to maintain, I can help audit the system, stabilize development, improve architecture, and create a safer long-term technical foundation. 👉Building MVPs that can grow after launch I focus on practical MVPs: the smallest version that proves the core workflow, supports real users, and does not become a throwaway prototype. The goal is not only to launch quickly, but to build something maintainable enough to keep improving. 👉Transparent collaboration You will always know what is being worked on, why it matters, and how much time was spent. I work with clear communication, structured project management, weekly progress reports, time tracking, QA cycles, and straightforward expectations. 👉Long-term support and ownership You own the product, the code, the accounts, and the direction. I can also support the product after launch with bug fixes, OS updates, monitoring, performance improvements, security checks, and ongoing feature development. BACKGROUND ✅10+ years of professional experience in mobile app development, web development, backend systems, product architecture, and long-term software support. ✅Worked on large-scale products for companies including Volkswagen, Bosch, and Invisalign. ✅Delivered mobile apps, web apps, backend systems, admin dashboards, AI features, marketplace-style platforms, and workflow-heavy business tools. ✅Strong experience with: - iOS, Android, React Native, Kotlin, Swift, SwiftUI, Jetpack Compose - Web apps, SaaS platforms, admin dashboards - Backend development, APIs, authentication, databases, cloud infrastructure - AI assistants, RAG, document search, workflow automation - QA, deployment, app store release, monitoring, and support My focus is simple: understand the business problem, build the right product, communicate clearly, and stay available after launch. If you need a reliable technical partner for a serious mobile, web, SaaS, AI, marketplace, or operations platform, send me a message and I’ll walk you through the safest way to build or improve it.

Top 1% Expert-Vetted Freelancer on UpWork ✅ Hi 👋 I’m Gabe. I’m an AI-native senior product engineer who uses modern AI tools to ship production-grade software faster — without sacrificing architecture, quality, or long-term maintainability. I have 10+ years of experience building and scaling apps for Fortune 500 companies and startups, especially in high-stakes systems where timelines are tight or codebases already exist. My stack includes Cursor, Replit, OpenClaw, and LLMs — used where they actually make sense to move faster and reduce bugs. Everything I ship is grounded in clean architecture and production-ready code. What I Bring to the Table 🧠 AI-Native Development – Faster iteration without sacrificing quality 📱 Mobile & Full-Stack Expertise – React Native (iOS & Android), TypeScript, React, Next.js, Firebase, Vercel, Railway 🚀 MVPs & Prototypes – From idea → working product quickly 🛠 Fixing & Scaling Existing Apps – Notifications, performance, migrations, stability 📞 Clear Communication – Realistic estimates, proactive updates, no surprises Why Work With Me? ✅ Top 1% on Upwork (Expert-Vetted) ✅ Fortune 500 + high-traffic production experience ✅ Strong ownership and long-term thinking ✅ Trusted to solve hard problems, not just ship features Testimonials ⭐ “Gabe was incredible. He went above and beyond.” ⭐ “Great estimates, great communication, and consistently high-quality work.” If you're building something that matters, send me a message describing the problem. I'll let you know within 24 hours if I'm the right fit.

I build mobile apps — the real kind, native, shipped to the store, used by actual people — and lately the AI systems inside them. I've been doing the first for 20 years and the second long enough to know where it actually pays off. I'm Expert-Vetted on Upwork (top 1% of talent), with 100% Job Success, 5,700+ hours, and $200K+ earned. Behind that is 20+ years in software — a decade architecting enterprise systems at Accenture for Fortune 500s, then CTO of a SaaS startup I scaled from 3 to 30+ engineers and took to consumer scale. I'm completing Stanford's AI Professional Program now. What you get is a CTO-caliber technologist who never stopped writing production code. I work two ways, depending on what you need: ⸻ * Mobile Apps — zero to App Store * (fixed-price) You have an idea or a validated concept; I deliver the finished app, live in the App Store and Play Store. Architecture, design, frontend, backend, deployment, and the part most people underestimate — actually getting through store review, native builds, push, Live Activities, the works. I've shipped 20+ mobile apps, several used by hundreds of thousands of people, and I handle the whole build personally. Shipping a native app to a store is a different discipline than deploying a web app, and it's the discipline I've spent years in. * AI Systems and other complex software — design & build * (hourly) Production AI/LLM systems, not prototypes. My recent work is a multi-vendor LLM pipeline that benchmarked 21 model-and-strategy combinations across Claude, GPT, and Gemini over 54 recipe sources in 7 countries — automated quality scoring against an Opus gold-standard reference, and cost tuned across a 150x price spread down to the best quality-per-dollar. The hard part of AI work isn't calling an API; it's knowing where AI actually earns its keep, which model fits which job, and how to architect a pipeline that holds up in production. That's what I do, then I build it — often straight into the mobile products above. ⸻ The background behind that: 10 years at Accenture on large-scale systems for Fortune 500s in healthcare, telecom, oil & gas, and retail. Then CTO at a SaaS startup — engineering scaled 3 to 40, a multi-service platform shipped with payments, identity, and real-time processing running at consumer scale. 📎 Stanford — AI Professional Program (completing August 2026) 📎 Kellogg — Product Strategy 📎 TOGAF Certified Enterprise Architect ⸻ Native Mobile (React Native / Expo, App Store & Play Store delivery) · TypeScript/JavaScript · LLM APIs (Claude, GPT, Gemini) · Prompt Engineering · Multi-Model Pipelines · React · Next.js · Node.js · Supabase · PostgreSQL · AWS · Solution Architecture

Hi! I’m a full-stack web and mobile developer with a passion for turning ideas into reality — even if that reality lives in pixels. I help small and medium-sized businesses build clean, functional websites and apps that look great and work perfectly. Whether you’re trying to grow your business, sell online, or launch a mobile app — I’ve got you covered. 💻 Web Development: • HTML5, CSS3, PHP, jQuery • RESTful APIs & backend logic • Database architecture (MySQL, PostgreSQL) • SEO and page speed optimization • Authentication systems (JWT, session-based) • Admin panels and dashboards 📱 Mobile App Development: • Flutter / Dart — cross-platform apps for iOS & Android • App Store / Google Play deployment • Barcode scanning, camera integrations • Push notifications and local storage • Role-based apps (admin, courier, picker, end-user) 🧠 AI & Smart Features: • Integration with OpenAI & Gemini APIs • AI-powered data processing and filtering • Food/allergen recognition and contextual analysis 🎨 Design & UI: • Adobe Photoshop & Illustrator • Clean, responsive, minimalist UI design • User-centered UX • Design-to-code implementation 🔧 Infrastructure & DevOps: • API integrations (payment systems, file storage) • Cloud storage optimization and caching strategies • VPS/server setup, domain & SSL configuration • Git version control From the first sketch to the final product, I handle the entire process with care and attention to detail. I believe in clear, regular communication and building long-term partnerships with my clients. Let’s bring your vision to life — one pixel at a time.

Helping Startups & Enterprises Build Reliable, AI-Enabled Systems I help companies overcome unstable systems, integration bottlenecks, and production bottlenecks - turning fragile codebases into scalable, reliable, and production-ready platforms. With 15+ years of experience in backend architecture, mobile apps, AI integration, and cloud deployment (AWS, Azure, GCP), I specialize in solving complex technical challenges that slow down growth or increase operational risk. My expertise includes: • AI & ML Integration: Structured prompt design, LLM evaluation loops, JSON outputs, and automation workflows • Backend Architecture & Microservices: Scalable, maintainable systems for web and mobile applications • Payments & Cloud Systems: Stripe integration, secure cloud deployment, CI/CD pipelines Recent results: • Reduced AI output variance and improved reliability across thousands of records for an enterprise client • Delivered microservices for a federal healthcare platform, improving notification delivery speed and system stability • Built production-ready payment and e-commerce systems, cutting manual processing by 80% If you need to stabilize a system, integrate AI into your workflow, or build a high-quality backend platform, I can help you do it efficiently and reliably. AI & Automation: Prompt Engineering, LLMs (GPT-4/5), NLP, Structured Output, Evaluation Loops, LangChain Backend & Web: Java, Python, Spring Boot, FastAPI, REST APIs, Microservices Mobile: iOS Apps (Swift) Databases: MySQL, PostgreSQL, Oracle Cloud & DevOps: AWS, Azure, GCP, CI/CD (GitHub Actions) Payments & APIs: Stripe, OAuth, Postman, Swagger Featured Projects: AI Evaluation Loop Platform Designed structured prompts and evaluation workflows for LLMs, improving model consistency and reliability across thousands of records. Impact: Reduced output variance and improved accuracy. Government Healthcare Microservice Platform Developed backend microservices for federal healthcare notifications. Impact: Improved delivery speed, reliability, and employee communication. Startup Fitness App (iOS) Built a mobile app capturing user data and integrated AWS cloud storage. Impact: Enhanced user experience and retention through seamless cloud integration. Baked Goods E-Commerce Platform Developed backend microservices with Stripe payments and admin dashboards. Impact: Reduced manual order processing by 80%, improving operational efficiency. Why Hire Me: Strategic Problem-Solver: I don’t just code — I solve technical challenges aligned with your business goals. Senior Expertise: 15+ years building scalable, production-ready systems. AI + Engineering: Integrating AI into workflows for consistent, reliable results. Reliable Communication: Clear, proactive updates and milestone tracking. Call-to-Action: Let’s discuss your project and explore how I can help you scale your system, integrate AI, or stabilize complex applications. High-impact, production-ready solutions start here.

Hello, I am Steve ✔️ I am an all rounded, digital solutions creator working with a small, very skilled, IT "seal" team. ✔️ My 100% focus is on building custom web & mobile applications with a bold, outstanding, and articulate design ✔️ I graduated with a Diploma in IT in 2001, a Degree in Computer Science in 2005, and a Master's Degree in Applied Computer Science in 2008 from the University of Maryland ✔️ Since 2011, we have served dozens of small & medium businesses, startups & individuals helping turn their ideas into reality. ✔️ We have successfully completed 3 projects funded by the federal government and done a project for Microsoft ✔️ If you want a reliable, serious, truly commited partner whom you can easily reach, I am here. ✔️ We enjoy what we do & want to keep building a strong reputation as reliable and trustworthy experts in providing technology solutions ✔️ Besides work, I love reading, ice skating, roller skating, traveling and speaking Here is some feedback from Upwork clients like you: ⭐ Stephen's strength is his timely communication. He tries his best to adhere to the specifications and feedback provided along the way and genuinely wants to create the best product and satisfy user needs. It was a very professional and transparent experience working with him. ⭐ Best developer on upwork. Will never use anyone again, This guy is the real deal and the best I've ever worked with ⭐ It was a great work by an Excellent Freelancer! ⭐ Great vision and ability to make sense of non-technical people like me. ⭐Steve did a great job. Working with him is a pleasure and very productive ⭐ I have had problems with some other freelancers in the past, so I posted a portion of a larger project as a test. Stephen amazed me with a flawless deliverable on the first try... ⭐Steve is great! Attentive and got the job done right! ⭐Great communication and quick responses. ⭐ Great Work. Pleasure to work with ⭐ A+++ ⭐Very professional. Great work and service. Thank you. ⭐A+ wirk again Stephen. Thank you ⭐Steve produced great webdesign and is very motivated to understand the clients vision ⭐Steve is a good webdesigner who invests time and energy to find out what the client has in mind for his project. I enjoyed working with him. ⭐Steve works hard and takes pride in his work. He pushes hard when he needs to and made sure we were satisfied with our apps and website work! ⭐Great and trustful freelancer with wonderful design skills. I highly recommend him for any freelance job. Core Expertise: ⚡️UI/UX and Design: Web & Mobile UI Design, HTML5, CSS3, JS, Bootstrap, Responsive design ⚡️Mobile: iOS development, (Swift + Xcode), Android development (Java + Android Studio) ⚡️Development: Custom PHP, Laravel, React, Angular, JQuery Framework, Yii, CodeIgniter, WordPress, Backend Systems ⚡️eCommerce: Custom eCommerce, Shopify, WooCommerce, Apple Pay, Google Pay, Stripe API, PayPal API, Amazon Payments, 2-Checkout, PayU, First Data