Full-Stack & Mobile App Developer | System Design Overview: I build applications that work — web apps, mobile apps, and the backend systems that power them. Web Development: React, Vue, Node.js, .NET, Python — frontend to backend, APIs to databases MSSQL, CosmosDB, NoSQL — data architecture that scales Azure cloud infrastructure, CI/CD pipelines, Docker — deployed and automated Mobile Development: Cross-platform apps with Flutter Native performance, clean UI, real functionality System Design: Microservices architecture Distributed systems built for reliability API design, authentication, security — the parts that make an app production-ready I handle projects from concept to deployment. You give me a brief, I build it, ship it, and keep you updated every step of the way. Whether you need a web dashboard, a mobile app, or a backend system that ties everything together — I can deliver. Stack: Flutter | Python | Rust | C# | .NET | Java | JavaScript | TypeScript | React | Vue | Node.js | MSSQL | CosmosDB | Azure | Docker | Git

Hello, I am a successful iPhone and Android App developer based in the USA near the Washington DC area. I have over 14 years of experience with mobile app design and website design. Your job will be fulfilled with the best talent and expertise.

28 years in infrastructure. The last two building with AI every day. I ship working software — Claude-powered apps, Terraform that actually deploys, AWS environments that pass audit — and I've saved clients north of $2M a year doing it. Here's what that means in practice. I'm not a bootcamp dev who read an LLM tutorial last month, and I'm not an architecture-diagram consultant who hasn't touched a terminal since 2019. I write the code, I deploy the infrastructure, and I stay on the hook when it breaks at 2am. Twenty-eight years running production systems does that to you. WHAT I BUILD → AI & agent development Claude API integrations, LLM-backed features, agentic workflows, MCP servers, RAG pipelines. Structured outputs with real schema validation so the model can't hand you garbage. I build these in Python and Flask/FastAPI, with tests, because "the AI usually gets it right" is not a production standard. → Cloud architecture & IaC AWS design and buildout — multi-region, multi-account, zero-trust. Terraform and OpenTofu written as reusable modules with remote state and GitOps workflows, not a 2,000-line main.tf someone copy-pasted from a blog. AWS Certified Solutions Architect and SysOps Administrator. → Security hardening & compliance FIPS 140, STIG, PCI-DSS, SOC 2, HIPAA. Container hardening, CVE remediation pipelines, vulnerability scanning on a real patch cadence. I've walked organizations through PCI audits with zero critical findings and hardened container platforms for aerospace clients. → Python & Bash automation The unglamorous work that pays for itself in a month. Boto3, Lambda, Step Functions, Glue. I've written automation that ran across hundreds of AWS accounts and cut storage spend by double-digit percentages. PROOF, NOT ADJECTIVES • $2M+ in recurring annualized savings delivered across Fortune 500 cloud engagements at Ernst & Young • Primary technical SME for 18 engineering teams inside CMS.gov's secure AWS environment — federal healthcare, real compliance stakes • Cut deployment time from days to minutes with modular Terraform and GitOps guardrails • 99.99%+ uptime on a commercial identity platform as part of an 8-person SRE team • Architected the oil & gas industry's first cloud-native well process control network — legacy SCADA to AWS, nine months, on time and under budget • Senior Technical Account Manager at Amazon Web Services — I've seen how AWS wants you to build it, and where that advice stops being practical HOW I WORK I ask what you're actually trying to accomplish before I write a line of code. Half the requests I get have a simpler answer than the one in the brief, and I'll tell you when that's the case — even when the simpler answer bills fewer hours. You get working code, documentation someone else can follow, and a handoff that doesn't leave you dependent on me. I've handed off enough systems to know the difference between a deliverable and a hostage situation. Everything is in Git. Everything is reviewable. If you want to see progress mid-project, you can. WHAT I'M NOT I don't do frontend design work, WordPress, or mobile apps. I don't take "rewrite my entire platform" projects on a fixed bid with a two-week timeline. And I won't tell you AI solves a problem it doesn't solve — I use these tools daily and I know exactly where they fall over. If you've got infrastructure that needs building, an AI feature that needs to actually work in production, or a cloud bill that's gotten away from you — send me the details and I'll tell you straight whether I'm the right fit. - John Reed

I build Mobile apps ( React Native ) that are robust, fast, stable to use for businesses ( from early startups to large scaled ) — the kind that don't crash, don't lag, and don't need a rewrite Over 8.5+ years I've led mobile teams and shipped consumer apps at scale for companies like Zepto, Cars24, and Gameskraft. A few numbers from real products: ⭐ 99.97% crash-free and 99.99% ANR-free rates at scale ⭐ Buttery smooth screens ( UIs ) ⭐ Improved FPS from 42 to a smooth 60, cut CPU usage by 40% ⭐ 5x faster data flow and 10x smaller image payloads ⭐ Proactive communication for visibility and transparency ⭐ Predictable ETA/Execution and releases of project HOW I CAN HELP YOU: ✅ Build a new app (iOS + Android) from scratch — clean, scalable architecture ✅ Rescue a broken app — fix crashes, ANRs, freezes, memory leaks, and jank ✅ Buttery 60 FPS gaming animations & gestures (Reanimated, Gesture Handler) ✅ Native modules & bridging (iOS/Swift, Android/Kotlin) ✅ Payment integrations — Stripe, Razorpay, Juspay, Adyen, UPI ✅ CI/CD & instant updates — Bitrise, Fastlane, CodePush OTA, store releases MY STACK: React Native, React.js, TypeScript, Expo, Redux/RTK, React Query, Reanimated, Flashlist, Native Modules, Node.js, GraphQL, AWS, Crashlytics, Sentry. I've led teams of 7-8 engineers, so I communicate clearly, plan realistically, and care about your product — not just closing a ticket. You'll always know where things stand. Whether you're starting a new app or fixing one that's falling apart, send me a message with your project. I'll reply with honest, specific input on the best way forward — no generic sales pitch.

Algorithmic Trading Systems | Quant AI R&D | NEXUS I'm Jack, Founder & CEO of AlgoXpert — a quant AI firm that builds, validates, and deploys algorithmic trading strategies across FX, equities, crypto, and options. We don't guess. We engineer. LIVE TRACK RECORD (real money, publicly verified on MyFxBook): • Sharpe 3.15 over 50+ days of live trading (since Jan 2026) • Max drawdown: 3.54% • Strategies: FX majors (USDJPY) • Full transparency — every trade independently verified THE ENGINE BEHIND THE RESULTS — NEXUS: NEXUS is our proprietary Agentic AI R&D system that produces verified alpha strategies at 100-1000x the speed of a traditional quant desk: • 60+ strategies developed across FX, crypto perps, and SPX options • 10 production-grade champions through our 7-layer validation engine • 1,000+ research studies completed | 24 active R&D projects • Out-of-sample validated: Crypto Sharpe 2.0 (2021-2026), SPX 0DTE Sharpe 3.4-6.4 • Prop firm strategies: 88% simulated pass rate across 5,000 Monte Carlo paths WHAT I BUILD: • Expert Advisors (MQL4/MQL5) — XAUUSD, EURUSD, indices, custom pairs • Pine Script strategies & indicators — TradingView, webhook automation • Python quant systems — backtesting, optimization, signal generation • Trading bots — Telegram copiers, API integrations (IB, MT4/5, NinjaTrader) • Full systematic trading frameworks — research to deployment HOW WE WORK TOGETHER: 1. Custom quant builds — EAs, bots, systematic frameworks ($2K-$15K) 2. FTMO/prop firm alpha packages — strategies engineered for challenge rules 3. Strategy licensing — own a validated strategy set, run it yourself 4. Signal subscription — copy our live trade signals directly 5. Managed accounts — we deploy and manage strategies on your capital 6. Consulting/mentoring — learn systematic trading from a practitioner 14+ projects delivered on Upwork | Rigorous validation on every build | No curve-fitted backtests, ever. Note: All out-of-sample and simulation metrics are validated through walk-forward analysis and Monte Carlo testing. Live results are independently verified on MyFxBook. Past performance does not guarantee future results. Jack / Founder & CEO, AlgoXpert Quant AI & Trading Systems

I'm a highly experienced Flutter & iOS developer, always innovating with my code and doing the best practices to make it clean and organized, I have built several apps using or not serverless technologies. You can also check out my Portfolio and see my previous works. I really love what I do and is a great passion of mine to work with Mobile Development. I am confident enough to prove my best capabilities to create any kind of application that you need. I am still new here on Upwork but I am sure that with my efficient work I can get your positive review and start my career on this platform. Think I’m the perfect fit for your project? Just send me a message! Thanks for reading, and I look forward to (hopefully) working with you!

I have been working in .NET since the .NET 2.0 version, and have great experience in website development using ASP.NET, ASP.NET MVC, Python, LangChain, Postgres, SQL server, HTML, HTML 5, CSS, Entity Framework, JavaScript, jQuery, Angular, Vue, React . I have a lot of experience in architecting, implementing and delivering end to end solutions. My unique ability comes in understanding what the client's bigger goal is and helping him achieve that goal by providing him technology suggestions and also implement those suggestions to his satisfaction.

Most app and game ideas die as half-finished prototypes. We take them the whole way: design, engineering, polish, and store submission — for iOS, macOS, and Android. We've shipped our own commercial titles end-to-end: Apex Drift (live on the App Store), FileCura for Mac, Triagles, and Eclipse Run. Design, engineering, art direction, release — all of it, in-house. We've done the thing we're offering to do for you. HOW WE WORK Every project starts with a fixed-price discovery milestone — the Blueprint. In 10 working days you get a written build plan: locked scope, technical approach, milestones, timeline, and a fixed quote to build. It's yours to keep and act on, whether you continue with us or not. If we build together, the discovery fee is credited against the build price. No hourly meters. No open-ended estimates. Fixed scope, fixed price, and a client sign-off gate at every phase — the next phase doesn't start until you've approved the last. WHAT WE PROMISE (AND WHAT WE DON'T) Execution risk is ours: a finished, polished product that actually ships, on time and to the agreed scope. The market risk stays yours — no one can honestly promise downloads or revenue, and we won't. What we deliver is a product genuinely able to compete. A sample Blueprint is in our portfolio, so you can see exactly what the discovery milestone produces before you spend anything.

Hi 👋🏼 I'm Dylan Ta, a student and passionate Full-Stack freelance developer, excited about web and cutting-edge technologies. I design modern and high-performance applications in React, Node.js, TypeScript, etc., with a focus on clean, maintainable code. What I Offer: • Front-End Development: Dynamic, modern, and responsive interfaces with React, TypeScript, and HTML/CSS • Robust & Structured Back-End: Secure APIs with Node.js and database management • Complete Application Design: From prototype to production • Optimization & Debugging: Using tools like GDB, Postman, Docker to ensure stability • Consulting & Support: Assistance with technical choices, project structure, and best practices 🛠️ Tech Stack & Tools: Languages & Frameworks: JavaScript, TypeScript, React, Node.js, Python, C, C++ Databases: PostgreSQL, MariaDB Dev & Infrastructure: GitHub, Docker, Linux/macOS, SSH, Vite, CMake/Make, Postman IDE & Project Management: VSCode, Jira, DBeaver, Github Project Testing & Debugging: Criterion, GDB, GCC 🔁 My Methodology: 1. Kick-Off: Analysis of needs and clear objectives 2. Architecture & Planning: Appropriate technical choices and action plan 3. Agile Development: Short iterations, frequent feedback, regular deliverables 4. Production & Follow-up: Reliable delivery, support, continuous improvement 🎯 Why Work With Me? ✓ Complete development vision: front, back, infrastructure, and deployment ✓ Smooth and transparent communication ✓ Clean, maintainable, documented code ✓ Ability to adapt to different environments and needs

I'm a versatile developer and designer specializing in web development, graphic design, and Java/JavaFX applications. I help clients bring their ideas to life through clean, functional websites, visually compelling designs, and well-structured software solutions, using tools like HTML, CSS, JavaScript, React, and Figma to create modern, user-friendly interfaces alongside polished branding and visual content. I'm currently a software engineering student, which keeps me sharp on the latest tools, technologies, and best practices in the field, and I take a detail-oriented approach to every project, focusing on quality, clear communication, and delivering work that meets and exceeds client expectations. Whether you need a complete website, a standout design, or a custom Java application, I'm committed to turning your vision into reality, on time and within budget.