With 25+ years of hands-on technology leadership experience, I serve as a Fractional CTO specializing in AI/ML, Cloud Architecture, Cybersecurity, and Application Development. I’ve worked with global brands including Walmart, FIFA, Porsche, Deloitte, and Covestro, helping them solve complex technical challenges and deliver high-impact solutions. I specialize in three core areas: AI & Machine Learning — Over a decade of real-world experience building AI solutions long before it became mainstream. Application Development — Designing and delivering robust web, mobile, and backend applications that turn ideas into reality. Cybersecurity — Architecting secure systems and maintaining ongoing security excellence through regular testing and best practices. As a Fractional CTO, I provide high-level strategic leadership without the full-time cost. I help companies: Align technology with business goals Build scalable, secure architectures (AWS & Azure) Reduce technical debt Accelerate product development Strengthen cybersecurity posture Whether you need interim leadership, a technology roadmap, AI implementation, or help scaling your systems securely — I deliver practical, results-driven solutions that drive real business growth. I’m known for clear communication, deep technical expertise, and the ability to bridge the gap between business needs and technical execution. Let’s talk about how we can work together to move your technology forward.

I am a full-stack mobile app/web service developer. During my 25-year programming experience, I have succeeded in many projects with different technologies and programming languages be it an embedded system or an encrypted mobile communication service. I have always enjoyed helping give birth to a new app or service. In my work, my code is very simple: to remove your headache. I am interested in: - Cordova Plugin development - Capacitor Plugin development - Hybrid app development (React Native/Ionic/Cordova) - React JS development - AWS, Firebase, - API development - Android native app development - iOs native app development(Objective-C/C++) - Integrating/migrating your legacy (C/C++) lib to Android (JNI, NDK) - ME(R/A)N(Mongo/Express/React Native/Angular/Node) projects Whether it is a project of 15+ or of a single developer you can count on my 15+ years of experience in the mobile/embedded industry, ps: I am sorry that I haven't taken any tests, but having sites with all the solutions for the tests makes them quite difficult to rely on.

Nice to meet you 🎨✨ I'm Kostiantyn, a UI UX designer, product designer, UIUX designer, and web designer specializing in Mobile App Design, Web App Design, SaaS platforms, Dashboard Systems, and AI Products. As a figma specialist and landing page designer, I help startups and founders create user-friendly digital products with strong user experience, intuitive interfaces, and development-ready systems built on conversion rate optimization principles. With 600+ projects delivered across Mobile Apps, Web Apps, SaaS Platforms, Ecommerce, AI Products, Healthcare, Marketplaces, Dashboards, and Fintech - I work as a UI UX designer, web designer, graphic designer, saas designer, and landing page designer who understands the full picture from first wireframe to final handoff. ✅ What I do as a UI UX Designer, Web Designer, and Product Designer ❇️ Mobile App Design & Mobile UI UX As a mobile app ui ux designer and UI UX designer, I design for iOS and Android - covering onboarding flows, mobile ui ux navigation, and retention-focused mobile app design. Every mobile app design I deliver as a figma app designer is grounded in conversion rate optimization and real user behaviour. My mobile ui ux work spans healthtech, fintech, edtech, and marketplace products. Strong mobile app design requires both UIUX designer thinking and graphic designer craft working together. As a UIUX designer and saas designer with mobile experience, I treat every mobile app design project as a product problem first. ❇️ UI UX Design for SaaS & Web Apps As a SaaS designer, UIUX designer, and product designer, I build interfaces for analytics platforms, admin panels, and complex dashboards. My saas designer approach combines ux designer strategy with figma ui ux execution - delivering scalable systems. Whether you need a ui ux designer saas, ui ux dashboard, or full web design rebuild, I deliver as a ui ux designer figma and ui ux designer react specialist. Every saas designer engagement starts with a ux designer audit before any screen is touched. ❇️ Figma Design, Prototyping & Design Systems As a figma designer, figma ui designer, and UIUX designer, I deliver high-fidelity wireframes, prototypes, and figma ui design systems. I handle figma to webflow, figma to react, figma to wordpress, figma to shopify, and figma to next handoffs. Every figma app designer deliverable and figma landing page is built for developers to implement without guesswork. Whether you need a figma designer for a web design project or a figma ui designer for a full design system - I deliver. ❇️ Web Design, Website Design & Landing Pages As a web designer, website designer, and landing page designer, I create conversion rate optimization focused web design for SaaS, ecommerce, and startups. My web design spans wordpress website design, webflow ui ux, shopify website design, and wix web design - always delivered as a ui/ux web designer and website designer. As a landing page designer, I apply conversion rate optimization to every layout, CTA, and visual hierarchy. Every website design I deliver as a website designer is built to convert - because a landing page designer who ignores conversion rate optimization is just making art. Website design, web design, and website designer work are at the core of every engagement I take as a web designer. ❇️ Graphic Design & Visual Identity As a graphic designer, UI UX designer, and web designer, I cover logo design, brand identity, and visual systems. Strong graphic designer work is built into every product. Whether you need a graphic designer for a product launch, a web designer for website design, or a figma web designer for a landing page designer engagement - I bring the same graphic designer craft and UIUX designer discipline to every project. ❇️ UX Research & Information Architecture As a ux designer and product designer, I map user journeys, define information architecture, and build user flows that reduce friction. My ux designer process covers research, wireframing, and usability testing - giving every UI UX designer decision a strategic foundation. 📊 Results ✔️ 200+ projects as a UI UX designer, SaaS designer, web designer, UIUX designer, and graphic designer ✔️ Mobile app design for iOS & Android with mobile ui ux systems and figma app designer handoffs ✔️ Saas designer and ui ux designer saas work across dashboards and B2B platforms ✔️ Figma to react, figma to webflow, figma to wordpress, figma to shopify across 50+ products ✔️ Landing page designer work with proven conversion rate optimization results for SaaS and ecommerce ✔️ Graphic designer and website designer web design work across startup brands ✔️ Conversion rate optimization and website designer expertise across 50+ web design and landing page projects Have a product idea? Let's connect 🤝📩 and turn it into something people enjoy using ✨ Last updated: 29.07.2026

Currently I provide software development services of photo and video editing applications for iOS, iPadOS, macOS and visionOS. I offer the development of video and photo editing application from scratch or upgrading the existing app. For my solutions I use Swift and Objective-C programming language. The typical tasks which any video editing app consists are: – Video recording – Video stabilisation when recording – The screen capture at desired FPS – Video editing – Video generation (without source video file) – High FPS, 4K and HDR video edit and recording – Frame-by-frame video pipeline processing – Speech to text recognition – Video captioning and subtitles Functions that could be added to the new app or existing app – Reverse video – Crop & resize – Aspect ratio change – Change quality – Trim the video – Subtitles and captions – Stickers over video – Add watermark – Filter effects – Images to video – Audio overlay Let me know whether you have any questions about my solutions, tasks and functions that we could add into your app. Find and download the following apps in the AppStore as a demonstration of proof of experience: – Scrolling Credits Video – SubtitlerKit – Split Video Into Parts – Video Grid Collage _ Besides of video editing software experience, I have the experience in the development, support and maintenance of iOS software that is used by millions of people. I saw all the way how the project grows and turns from a startup to a big company. I understand the problems of both a small startup and a large company. My main services are: – The development of video recording and video editing applications for Apple devices – iOS, macOS, iPadOS and visionOS application development based on SwiftUI and Combine – The support of legacy applications and projects that were done in Objective-C programming language What will you get – Analysis of your problem and task – Working proof of concept in a week or a month depending on the complexity – Constant and clear communication on work and issues During all the time I had experience with: – Developing of iOS, Mac and MacCatalyst applications – C, C++, Objective-C, Swift – CoreData, SQLite, SQL – GCD, Mulththreading – Core Audio, AudioUnits, AVFoundation, AVKit, AVAudioEngine – AudioKit – GPUImage, Metal, MPS, CoreImage – CallKit, CoreTelephony – CoreText – SwiftUI, Combine – MapKit, MapBox, GoogleMaps – iOS Extensions – Debugging – CocoaPods, Carthage, SPM – JIRA, Trello, Slack, Figma – Scrum, Kanban, Agile – GIT, GitHub, BitBucket – MVVM, MVC – Data structures & Algorithms – Firebase, Testflight – Twilio SDK

I am a full-stack developer, specializing in mobile (iOS/Android), Wordpress and Social Media Marketing. After years of working with overseas Developers to help me build my very own startup, I noticed that besides being able to find Devs at a fraction of the cost, the majority of Devs found did very unprofessional work, they were not organized, did not test and had weak code/design skills. So where do bootstrapped startups go to develop their MVP's? I decided to be part of the solution. I now work with an amazing team of highly skilled developers/designers that understand the startup culture and specialize in fitting within a bootstrapped budget. I have experience working with startups; I’ve attended Founders Space, one of the top Incubators in the country based in San Francisco. Myself including our team have a wealth of knowledge when it comes to building a startup from an idea to a reality.

8 iOS apps shipped to the App Store. 100% Job Success on Upwork. I build iPhone and Apple Watch apps with AI features, and take them from idea to App Store approval in weeks, not months. I'm a solo iOS engineer and the founder of CYNQ Ventures, a mobile studio where I've designed, built, and shipped 8 apps end to end. Every part of the process you're hiring for is something I've already done on my own money and my own deadlines: architecture, UI, submission, rejection appeals, and the launch after. WHAT I BUILD • iPhone + Apple Watch apps - real-time sync, complications, standalone watchOS, hardware integrations • AI-powered features - OpenAI, Claude, and Gemini APIs wired into SwiftUI interfaces that feel native, not bolted on • Screen Time API and app blocking - one of the least documented frameworks on iOS; my open-source Screen Time toolkit is used by developers worldwide • Health and motion - HealthKit, CoreMotion, AirPods head tracking, CoreBluetooth • Monetization - RevenueCat, StoreKit 2, paywalls, and rescuing subscriptions when in-app purchases break • Launch assets - App Store screenshots, icons, and ASO copy, because I've optimized listings for my own apps and a dozen client apps HOW I WORK Bug fixes in 24–48 hours. Working prototype in 3–7 days. MVP in 1–2 weeks. You get a build you can hold in your hand every week, not a status update at the end of the month. I reply within 4 hours, flag problems before they turn into surprises, and tell you when something in your scope is a bad idea before you pay to build it. SELECTED WORK • Pongle - iPhone + Apple Watch live scoring with Flic button integration • LockIn Daily - Screen Time API focus app • UpRight - posture coach using AirPods motion data • StrideGate - HealthKit walk-to-unlock • NetCal - AI calorie tracking Whether you need a new app built, a stuck build rescued from App Review, or a listing that actually converts - send me the details and I'll tell you honestly whether I'm the right person for it.

I build and scale production-grade 𝗔𝗜, 𝗦𝗮𝗮𝗦, 𝗮𝗻𝗱 𝗳𝗶𝗻𝘁𝗲𝗰𝗵 𝘀𝘆𝘀𝘁𝗲𝗺𝘀 that handle real users, real data, and real business constraints, not prototypes or proof-of-concepts. With 𝟭𝟯+ 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗳𝘂𝗹𝗹-𝘀𝘁𝗮𝗰𝗸 𝗲𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 𝗲𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲, I work across backend architecture, frontend systems, cloud infrastructure, and AI integration to deliver platforms that are built for reliability, scalability, and long-term maintainability. 𝗖𝗹𝗶𝗲𝗻𝘁𝘀 𝘁𝘆𝗽𝗶𝗰𝗮𝗹𝗹𝘆 𝗵𝗶𝗿𝗲 𝗺𝗲 𝘄𝗵𝗲𝗻: • They are building a SaaS or AI product that needs to scale beyond MVP • Their backend or architecture is becoming unstable under real usage • They need secure, production-ready fintech or payment systems • They are integrating AI into real workflows (not just chat demos) • They need senior-level ownership across full product delivery 𝗪𝗵𝗮𝘁 𝗜 𝗯𝘂𝗶𝗹𝗱: • AI-powered systems that automate real business workflows • Multi-tenant SaaS platforms with billing, roles, and scalable architecture • Fintech backends with secure payments, audit trails, and reliability-first design • Marketplaces and LMS platforms designed for high user concurrency • Cloud-native systems on AWS and Azure with CI/CD and deployment pipelines 𝗛𝗼𝘄 𝗜 𝘄𝗼𝗿𝗸: I operate 𝗹𝗶𝗸𝗲 𝗮 𝗽𝗿𝗼𝗱𝘂𝗰𝘁-𝗳𝗼𝗰𝘂𝘀𝗲𝗱 𝗲𝗻𝗴𝗶𝗻𝗲𝗲𝗿, not just a task executor. That means: • I design systems with scalability and failure modes in mind • I flag architectural risks early, before they become expensive problems • I prioritize clean structure, maintainability, and production stability • I take ownership from architecture → build → deployment 𝗧𝗲𝗰𝗵 𝘀𝘁𝗮𝗰𝗸: React, Next.js, Node.js, Python, .NET MongoDB, PostgreSQL AWS, Azure AI integrations (LLMs, automation systems, APIs) CI/CD, system architecture, cloud deployments 𝗗𝗲𝗹𝗶𝘃𝗲𝗿𝘆 𝗺𝗶𝗻𝗱𝘀𝗲𝘁: You won’t need to chase updates or manage micro-details. I communicate clearly, surface risks early, and ensure systems are built to production standards, not just “working code.” If you're building a serious product and need someone who can own architecture + execution end-to-end, I’m available for short-term builds or long-term engineering support.

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.

⭐ Specialized in Mobile App Development | Flutter, Kotlin & Swift | iOS and Android ⭐ 6+ Years of Advanced Programming Experience ⭐ Expert in Crafting High-Performance Mobile Applications Featured Projects and Achievements: 🔵 'Ihre Apotheken' App Transformation Led the transformation of the Ihre Apotheken app into a robust digital health platform for German pharmacies, achieving 100k+ downloads and a 4.5 App Store rating. Technologies: Flutter, Dart, Firebase, Riverpod 🔵 Revlum Offerwall SDK Development Developed Android and iOS SDKs for Revlum, enabling seamless configuration and launch of an offerwall WebView for user rewards. The Android SDK was built with Jetpack Compose, Koin, Retrofit, and DataStore, deployed as a binary to AWS S3. The iOS SDK used SwiftUI, UIKit, async/await, and URLSession, published as an XCFramework to GitHub releases. Created Flutter and React Native plugins published on pub.dev and npm. 🔵 MAF iOS SDK Redevelopment Fixed a non-functional iOS SDK for MAF, built with UIKit and WebView (WebKit), distributed as an XCFramework via SPM to GitHub releases. Improved integration documentation. 🟠 Car Rental Application Enhancements Enhanced a car rental app, integrating deep linking with uni links and the Smartcar API for contactless lock/unlock functionality. Fixed bugs and refined the codebase. 🟠 PiP App Overhaul Converted the PiP app from Android to Flutter, improving task scheduling and data management. Migrated from Room to Isar for NoSQL performance. Technologies: Flutter, Isar, Firebase, Sentry 🟠 Aplauz Digital Wallet Enhanced UX with biometric authentication and automated localization. Built with Flutter and Riverpod for robust architecture. Technologies: Flutter, Python, Riverpod 🔵 ChatGPTool Developed a Flutter-based app integrating OpenAI's ChatGPT and Whisper APIs for streamlined company communication. Used Firebase for backend services like authentication, cloud storage, and serverless functions. Technologies: Flutter, Firebase, OpenAI APIs ⚫ myKiK POS & Loyalty App Led the development of the myKiK app for KiK Textile & Non Food B.V., building a retail and loyalty platform with Flutter Bloc, Retrofit, and CI/CD via Jenkins. Technologies: Flutter, Bloc, Retrofit, Jenkins 🔵 FootFact Developed a machine-learning-driven app for precise foot measurements, integrating offline-first functionality with Dio, Floor database, and Firebase Authentication. Technologies: Flutter, Firebase, Dio, Floor Database 🟠 Spective Connect IoT Developed an IoT solution addressing WiFi disconnection issues and adding service reporting features using MQTT Protocol and Jetpack components like Room. Technologies: Kotlin, MQTT Protocol, Firebase Analytics 👨‍🏫 Lecturer at Algebra University College, Zagreb Led a 6-month, 230+ hour Android development course, covering Kotlin, Android SDK, Room, Coroutines, Retrofit, MVVM, and clean architecture principles. 🎓 MSc in Computer Engineering Proud graduate of Josip Juraj Strossmayer University, Croatia. 🌟 Why Choose Me? Client-Centric Solutions: I meet project requirements while exceeding expectations. Innovative Problem Solver: I deliver impactful, scalable solutions. Reliable & Communicative: I ensure seamless workflows and client satisfaction. 😁 Ready to elevate your mobile application? Let’s connect and discuss your project needs!

Hello! I’m a CTO, Senior .NET Core Developer, AI Developer, and AI Agent Developer with 20+ years of experience in enterprise software engineering, cloud architecture, SaaS development, distributed systems, and AI Development. I have delivered 150+ AI projects, launched my own production AI products, and created the Managed Code Coding AI Framework (MCAF) — a structured framework for applying AI across the software development lifecycle while preserving engineering quality, governance, security, and predictable delivery. My work combines advanced AI Development with deep expertise in C#, .NET Core, Microsoft Azure, Orleans, enterprise architecture, and operational automation. What I Build • AI agents and multi-agent systems • AI chatbots, copilots, and intelligent assistants • OpenAI- and Claude-powered applications • RAG and enterprise knowledge systems • AI SaaS products and internal platforms • Workflow and business process automation • Scalable .NET APIs and distributed cloud systems • AI integration for existing and legacy software I work as an AI Developer, AI Software Developer, AI Chatbot Developer, AI App Developer, OpenAI Developer, Claude Developer, and AI Agent Developer. AI Agent Architecture I specialize in the systems layer that transforms an LLM into a reliable production-grade agent. My expertise includes: • Agent harness architecture • Execution, reasoning, and control loops • Multi-agent orchestration • Tool calling and task delegation • Context, memory, and state management • Guardrails, governance, and access control • Human-in-the-loop approval workflows • Validation, retries, fallbacks, and recovery • Agent evaluation, tracing, and observability An effective AI agent is not simply a model connected to an interface. It requires a complete operational architecture around the model: tools, permissions, memory, business rules, execution control, monitoring, and failure handling. Managed Code Coding AI Framework I created the Managed Code Coding AI Framework (MCAF) to help engineering teams adopt AI in a controlled, measurable, and scalable way. MCAF provides a structured approach to: • Integrate AI into software delivery workflows • Improve developer productivity without reducing code quality • Introduce governance and validation into AI-assisted development • Standardize how teams use AI across analysis, coding, testing, and documentation • Reduce delivery time and repetitive engineering work • Preserve security, maintainability, and architectural consistency The framework is designed for organizations that need more than isolated AI tools. It helps transform AI usage into a repeatable engineering capability. Business Value My objective is not to add AI for its own sake. I design systems that create measurable operational and financial value. Depending on the process, my solutions can: • Reduce manual workflow steps by 40–80% • Convert hours of repetitive work into minutes • Reduce AI and token costs by 30–70% • Improve system reliability through validation and fallback logic • Accelerate product delivery and internal decision-making • Increase process consistency and reduce human error • Extend existing teams without proportional headcount growth I focus on the full cost of ownership, not only initial development. This includes model usage, infrastructure, maintenance, observability, security, and long-term scalability. AI Cost Optimization I optimize AI systems through: • Model routing • Semantic and response caching • Prompt and context optimization • Selective retrieval • Context compression • Token budgeting • Structured outputs • Small-model and large-model escalation • Usage monitoring and cost controls This allows companies to maintain response quality while reducing unnecessary token usage, latency, and infrastructure expenses. Core Technologies C#, .NET Core, ASP.NET Core, Microsoft Azure, Azure OpenAI, OpenAI API, Claude API, Orleans, Aspire, RAG, vector and hybrid search, REST APIs, microservices, Docker, Kubernetes, DevOps, CI/CD, and MCAF. I can take a project from discovery and architecture to implementation, deployment, optimization, and long-term support—whether the goal is to build a new AI product, modernize an enterprise platform, introduce AI-assisted development, or automate complex business operations.