As a dedicated individual developer, I specialize in creating high-quality, solution-driven software applications, drivers, and installers for Windows, Mac, Linux, and mobile platforms. Here are my specializations: Development: 🔹Microsoft Windows: 1. Windows GUI apps in C# .NET (WinForms, WPF, .NET 6.0/7.0, UWP), C++ (MFC, QT) 2. WiX Toolset, InstallShield, InnoSetup for Windows installers (msi and exe) 3. Windows Kernel and User mode drivers (KMDF, UMDF) 4. API libraries (REST, IPC, Web Sockets) 5. USB HID device, serial port (USB virtual serial port and RS232) applications and drivers 🔹Apple Mac: 1. MAC GUI apps (Objective-C, Swift) 2. MAC Package Installers, launch daemons, dylibs and scripts 3. System Extensions, Driver Kit drivers 4. Code signing, notarization 🔹Linux: 1. GUI apps in C++ (QT Creator) 2. Installers for applications and video and audio plug-ins using Makeself 🔹Mobile Apps: 1. iOS apps (Native apps in Objective-C, Swift using XCode, Cross Platform app in Visual Studio .Net Maui) 2. Android apps (Native apps in Android Studio) 🔹Cross Platform: 1. Java apps (Swing Forms/Applets, JNI) 2. Web apps (HTML, JavaScript) 3. .NET Maui, Mono, Electron Desktop apps 4. QT C++, CMake build, Conan package manager 5. Python GUI app with PyQt, Python app packaging with Pyinstaller 6. Chrome Web Apps (WebUSB, WebSerial, WebHID, WebMIDI) 🔹Development tools: 1. Visual Studio 2022 Community Edition 2. Windows 11 WDK 3. XCode for MAC 4. QT for Windows, MAC, Linux 5. InstallShield 2020 Pro Edition 6. WiX Toolset v3 and v4 7. Visual Studio Code 8. Git for version control, CI/CD pipelines. 9. USB port sniffer tools: SysNucleus USBTrace, HHD USB Monitor 🔹 Deployment: 1. JAMF and Mosyle - Deployment of Mac & iOS apps and custom configuration profiles, Apple Business Manager integration. 2. Microsoft Intune - LOB app deployment to Enterprise Windows PCs, Apple Mac and iOS devices. 🔹Notable projects: 1. Virtual Camera Driver (Win & Mac) 2. Virtual Serial Port Driver (Win) 3. API libraries for getting presence and call information from UC apps such as Microsoft Teams, RingCentral, Slack, Zoom, Bria, Cisco Jabber, Cisco WebEx, Genesys Cloud 4. USB Access Manager (Win & Mac) 5. HID mini driver for UPS Battery 🔹Reverse Engineering: Familiar in reverse engineering USB HID devices to identify its HID descriptors and Communication Protocol.

🚀 Welcome to my Upwork Profile! 🚀 📱 Mobile App Development | Flutter Expert | Top-Rated Seller Are you in need of a seasoned mobile app developer who can turn your ideas into stunning, functional, and user-friendly apps? Look no further! With over 4 years of experience in the ever-evolving world of mobile app development, I'm here to bring your vision to life. 🔥 What I Offer: 📌 Flutter Mastery: Flutter is my playground! I've honed my skills to perfection, and I take pride in creating cross-platform apps with a rich and responsive UI. 📌 Full-Cycle App Development: From concept to deployment, I handle it all. I can assist you at every stage of the app development process, from ideation, design, coding, testing, to launching your app on the app stores. 📌 Custom Solutions: Your project is unique, and so is my approach. I tailor my solutions to fit your specific needs, ensuring your app stands out from the crowd. 📌 Quality Assurance: Bugs and glitches have no place in my work. I meticulously test and debug every aspect of your app to ensure a smooth, seamless user experience. 📌 Timely Delivery: I understand the importance of meeting deadlines. You can count on me to deliver high-quality work on time, every time. 📌 Responsive Communication: Communication is key to a successful project. I'm always available for updates, feedback, and clarifications. 💼 My Expertise Covers: ✅ Flutter App Development ✅ UI/UX Design ✅ RESTful APIs ✅ Firebase Integration ✅ Cross-Platform Development ✅ App Optimization ✅ Third-Party Integrations ✅ Maintenance & Support 👍 Why Choose Me: 🌟 Top-Rated Seller: My track record on Upwork speaks for itself. I've consistently delivered exceptional results, earning the trust and satisfaction of my clients. 🌟 Client-Centric Approach: Your success is my priority. I work closely with you to understand your objectives and deliver solutions that align with your goals. 🌟 Innovative Solutions: I keep up-to-date with the latest industry trends and technologies, ensuring your app is modern, efficient, and competitive. 🌟 Professionalism: I maintain the highest standards of professionalism, from communication to project execution. Let's discuss your project and bring your app idea to life. Whether you're a startup, an established business, or an individual with a brilliant concept, I'm ready to help you achieve your mobile app goals. Get in touch today, and let's turn your vision into a reality! 📞 Contact Me: Don't hesitate to reach out if you have any questions or want to discuss your project. I'm just a message away, and I'm excited to work with you.

Software engineer with decades of experience delivering apps. I love working on mobile apps and desktop apps. I can do kernel programming, UI/UX design, and everything in between. I've worked on software used by thousands of developers that runs on millions of mobile devices. I've worked on games, programming languages, operating systems, device drivers, emulators, and applications for all major platforms, from simple file utilities to large user-friendly data analytics suites. Platforms - iOS - Android - Mac - Windows - Linux (various distributions: Ubuntu, RHEL, etc.) - Unix (NetBSD, FreeBSD, and OpenBSD) - tvOS & watchOS Frameworks & libraries - UIKit, AppKit, SwiftUI, Core Data, Core Animation, StoreKit, Core Graphics, Core Image, Model I/O, Image I/O, AVFoundation, Core Audio, Core Video, Core Media I/O, WebKit, JavaScriptCore, etc. - Android SDK, Android NDK, Android WebView, etc. - Win32, .NET, Direct3D, DriectShow, Driect2D, WPF, .NET MAUI, etc. - cURL, SDL, SQLite, OpenGL, FreeType, Cairo, Pango, FFmpeg, Qt, GTK, Electron, etc. Games Engines - Unity, Godot, Defold, Cocos2d, Irrlicht, Torque, Pygame, Panda3D, SpriteKit Drivers - Apple DriverKit and Microsoft Windows Driver Kit - HID, camera devices, and audio devices Web - HTML/CSS/JS - Node.js, Express, etc. - Ruby, Ruby on Rails, Sinatra, etc. - React, Vue.js, Next.js, etc. - Tailwind, Bootstrap, etc. - Progressive Web Apps (PWAs) - Go and the standard library for creating web services and web apps Additional - Competent with graphic art and design - Competent sound FX design - Knowledgeable in creating music and recording - Experience working with large open-source projects like WebKit, Linux, and Android - Experience publishing on App Store and Play Store

Greetings, AI-powered web code generators have begun to be used more seriously. However, AI in software development is still in its early stages, and there are some limitations to code generation, including: - Code Quality and Optimization - Limited Customization - Debugging Complexity - Scalability Issues This means that while AI can be a valuable assistant, human judgment is still necessary. A human developer must still intervene, review, and optimize the generated code to ensure it is maintainable and performant. Over the past 5 years, I have worked as a web developer and have gained extensive experience with web development technologies such as HTML/CSS, JavaScript/Typescript, React/Next.js, Tailwind CSS, and Supabase. With my experience, I can review and refactor AI-generated code to ensure high-quality solutions and appropriate customizations that meet client requirements and satisfaction. I look forward to further discussing your project. Best regards, Eric Carr

Are you looking for an AI developer who genuinely cares about your project, follows through on promises, communicates clearly, and can handle the entire development process without you having to manage a bunch of different people? If that’s what you need, we should talk. I don’t take on every project that comes my way. I only commit to projects I’m 100% confident I can deliver on because I want to make sure you get a top-notch result. (You can check out my reviews below.) I run a full-service AI and web development company that’s worked with big names like Wrangler Jeans, Atlas Copco, and Sims Recycling Solutions, as well as lots of small to mid-sized businesses. This means I’ve got the experience and know-how to bring the best practices to your project, with smooth communication and minimal hassle on your end. I’m guessing you’re here because you have a long-term vision. Unlike most freelancers, I’m all about building lasting relationships. If we end up working together, I want to be more than just a developer—I want to be your go-to tech consultant, helping you navigate growth, spot opportunities, and find creative solutions to any challenges that pop up. There are plenty of talented people out there, and I could go on about my experience (which you can see below), but what really matters is understanding your vision and making sure we’re on the same page. If this sounds like what you’re looking for, let’s chat.

I build and ship system software products end-to-end — from kernel-level Windows drivers to desktop applications and cloud integrations that sit on top of them. Over 25 years of experience gained from working at Intel, Xerox and Novell, and as an independent consultant, I've owned products that users and enterprises depend on. FxSound — an open-source Windows audio enhancer I direct and develop, with 3.7k GitHub stars and a 2,500-member community. TaxDome — cloud drive and print-to-cloud features on Windows, deployed across diverse enterprise environments. IDrive — Indirect Display Driver (IddCx) enabling a remote desktop product. Lookout — critical improvements to a SASE cloud security agent for Windows, including Modern Standby connectivity, application diagnostics and cloud integration. ePRINTit and MayuraTech — virtual printer drivers and cloud print solutions on Windows and macOS. I work best on projects where the technical depth is real — where the problem has stumped others, or where getting it right matters for your product's stability and OEM compatibility. Core: C, C++, C#, Windows Driver Kit (WDK), Win32, COM, .NET, WPF, WDDM, WFP, macOS, Swift, SwiftUI, Xcode

Welcome to my Upwork profile! With over 13 years of experience in the IT industry, I have established myself as a seasoned professional who is committed to providing exceptional service to my clients. Starting my career as a Software developer, I have worked my way up to become the CTO and Tech lead of my firm. My passion for coding has kept me up-to-date with the latest technologies, making me an expert in development, devops & infra, IoT, and customized solutions. With my years of experience and expertise, I have helped numerous clients achieve their business objectives through tailor-made technology solutions. I am a problem-solver at heart, and I am dedicated to delivering results that exceed expectations. Working with me means you can expect nothing but excellence. My commitment to quality, timely delivery, and attention to detail sets me apart from the competition. So, if you are looking for a highly skilled professional who can provide you with customized IT solutions that meet your specific needs, look no further! Let's work together to bring your ideas to life. Thanks for taking time to read my profile.

𝗬𝗼𝘂 𝗱𝗼𝗻’𝘁 𝗻𝗲𝗲𝗱 $𝟮𝟬𝗞 𝗼𝗿 𝟲 𝗺𝗼𝗻𝘁𝗵𝘀 𝘁𝗼 𝘃𝗮𝗹𝗶𝗱𝗮𝘁𝗲 𝘆𝗼𝘂𝗿 𝗮𝗽𝗽 𝗶𝗱𝗲𝗮. I’m Aatif, a 𝗦𝗲𝗻𝗶𝗼𝗿 𝗥𝗲𝗮𝗰𝘁 𝗡𝗮𝘁𝗶𝘃𝗲 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿 with 𝟲+ 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗲𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲 building production-ready mobile apps for iOS & Android. I help startups and growing businesses build 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧-𝐫𝐞𝐚𝐝𝐲 𝐦𝐨𝐛𝐢𝐥𝐞 𝐚𝐩𝐩𝐬 using 𝐑𝐞𝐚𝐜𝐭 𝐍𝐚𝐭𝐢𝐯𝐞, 𝐄𝐱𝐩𝐨, 𝐓𝐲𝐩𝐞𝐒𝐜𝐫𝐢𝐩𝐭, 𝐍𝐨𝐝𝐞.𝐣𝐬, 𝐅𝐢𝐫𝐞𝐛𝐚𝐬𝐞, 𝐒𝐮𝐩𝐚𝐛𝐚𝐬𝐞, 𝐑𝐄𝐒𝐓 𝐀𝐏𝐈𝐬, 𝐚𝐧𝐝 𝐆𝐫𝐚𝐩𝐡𝐐𝐋 so you can launch fast, get real users, and validate your idea in the market. We can start with a 𝗳𝗿𝗲𝗲 𝗽𝗿𝗼𝗱𝘂𝗰𝘁 𝗯𝗿𝗶𝗲𝗳 & 𝗮𝘂𝗱𝗶𝘁 to map the fastest path to your MVP. 𝐖𝐡𝐚𝐭 𝐈 𝐃𝐨 I build 𝘀𝗰𝗮𝗹𝗮𝗯𝗹𝗲, 𝗵𝗶𝗴𝗵-𝗽𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 𝗺𝗼𝗯𝗶𝗹𝗲 𝗮𝗽𝗽𝘀 𝗳𝗼𝗿 𝗶𝗢𝗦 & 𝗔𝗻𝗱𝗿𝗼𝗶𝗱 using React Native focused on real business outcomes, not just code. Whether you're: Launching an MVP Scaling an existing app Rebuilding for performance Adding AI, payments, chat, maps, or real-time features I handle 𝐞𝐧𝐝-𝐭𝐨-𝐞𝐧𝐝 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 from architecture to deployment. 𝐀𝐩𝐩𝐬 𝐈 𝐂𝐨𝐦𝐦𝐨𝐧𝐥𝐲 𝐁𝐮𝐢𝐥𝐝 Marketplace apps Uber / Airbnb style On-demand & booking platforms AI-powered mobile apps FinTech & payment-based apps Fitness & tracking apps E-commerce & food delivery apps Logistics, GPS tracking & driver apps Telemedicine & health apps Streaming, social, and real-time chat apps SaaS and productivity mobile apps 𝐂𝐨𝐫𝐞 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 React Native CLI & Expo iOS Development Android App Development Mobile App Development JavaScript TypeScript React.js Next.js Node.js REST APIs GraphQL Firebase / Firestore / Realtime DB Supabase Redux / Redux Toolkit API Integration User Authentication OTP & social login Stripe & payment systems Push notifications Real-time features Offline caching GPS tracking & maps App Store deployment Google Play Store deployment CI/CD with Fastlane, Jenkins, GitHub Actions, and Azure DevOps 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠 𝐀𝐩𝐩𝐫𝐨𝐚𝐜𝐡 I focus on what most developers ignore: Clean, scalable architecture Performance optimization smooth, fast apps Maintainable, production-ready code Strong testing & debugging Reusable components and clean state management Secure API and backend integration Clear communication & fast iteration Deployment-ready mobile app delivery 𝐑𝐞𝐬𝐮𝐥𝐭𝐬 & 𝐏𝐫𝐨𝐨𝐟 100+ apps launched 6+ years of mobile app development experience Built and scaled production-ready iOS & Android apps Worked on MVPs, marketplace apps, AI apps, FinTech apps, logistics apps, and e-commerce apps Built mobile apps reaching 20K+ active users Developed apps with 100K+ global downloads Helped clients generate $50K+ in revenue / MRR growth through scalable mobile solutions Delivered apps with authentication, payments, real-time features, APIs, dashboards, and store deployment 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐖𝐨𝐫𝐤 𝐖𝐢𝐭𝐡 𝐌𝐞 MVPs delivered fast Business-focused development, not just coding Senior-level React Native expertise Full-stack mobile app experience Long-term collaboration mindset Clear updates & reliable delivery Strong understanding of startup and product development workflows 𝐒𝐡𝐨𝐫𝐭 𝐏𝐢𝐭𝐜𝐡 Senior React Native Developer with 6+ years of experience building scalable mobile apps for startups and growing businesses. I don’t just build apps. I help you launch, validate, and scale. 𝗖𝗹𝗶𝗰𝗸 “𝗜𝗻𝘃𝗶𝘁𝗲 𝘁𝗼 𝗝𝗼𝗯” 𝗼𝗿 𝘀𝗲𝗻𝗱 𝗮 𝗺𝗲𝘀𝘀𝗮𝗴𝗲. I’ll review your idea and suggest the best way to build it.

🚀 Hey there! At the heart of my approach lies a deep commitment to ensuring your satisfaction above all else. Here's what you can expect when you choose to work with me: With over 15 years of hands-on experience in the industry, I've honed a unique blend of skills that meld the precision of an athlete with the artistry of software development. This approach has propelled me through countless projects, from collaborating with startups to servicing major organizations, always ensuring the highest quality output. When you partner with me, you're not just getting a developer—you're getting a dedicated ally committed to your project's success. Here's what you can expect: ⭐ A thorough understanding of your project's needs before we even begin. ⭐ Clear communication, transparency, and alignment on goals and expectations throughout our collaboration. ⭐ Code that's not just clean and efficient, but timeless—meaning it's easily maintainable and ready for future upgrades. ⭐ Timely deliverables and progress tracking using modern management tools, so you're always in the loop. ⭐ A hassle-free experience that allows you to focus on your product, confident that the operational details are in capable hands. But don't just take my word for it—here's what some of my clients have had to say about their experiences working with me: 💎 "Salman's communication skills are top-notch, and he's always there when I need him." 💎 "Salman seamlessly integrated into our team and delivered beyond our expectations!" 💎 "Extremely satisfied with Salman and his team—I wouldn't hesitate to work with them again!" 💎 "Exceptional work—fast, responsive, and truly exceptional." 💎 "Working with Salman has been a game-changer—I've never been this satisfied with a developer!" ⚡ Design / UI / UX: ✅ Figma ✅ Adobe Creative Suite ⚡ Front-end / Mobile Apps: ✅ HTML5 / CSS3 ✅ VueJS / ReactJS / Angular / AngularJS ✅ Bootstrap / Semantic UI / Quasar / Tailwind CSS / Material UI ✅ Progressive Web Apps (PWA) ✅ Android / Kotlin / iOS / Swift / Flutter / Ionic / Xamarin / Xamarin.Forms ⚡ Back-end: ✅ PHP / Laravel / RUST / Ruby on Rails / NodeJS / Python / Flask / Django ✅ Express.js / Koa.js / NestJS ✅ MySQL / MongoDB / PostgreSQL / Redis / SQLite / Cassandra ✅ Ubuntu / AWS / GCP / Docker / Kubernetes ✅ API / SM Integration ⚡AI / ML: ✅ TensorFlow / Keras / PyTorch / Scikit-learn / NLTK / SpaCy / OpenCV ✅ Reinforcement Learning (RL) / Genetic Algorithms (GA) / Recommendation Systems ✅ Neural Style Transfer / GPT (Generative Pre-trained Transformer) Models

**** Fractional CTO | MERN Stack Developer | ReactJS Developer | NodeJS Developer | Senior AI Engineer | Senior Solution Architect | Senior AI Architect | DevOps Engineer | AWS Expert | Azure Specialist | Cloud Engineer **** Hi, I’m 𝑨𝒍𝒍𝒂𝒏 𝑷𝒆𝒅𝒓𝒂𝒏𝒂, a Senior Full-Stack Software Engineer, AI Architect, and Cloud Solutions Expert specializing in MERN Stack, AWS, Azure, DevOps, CI/CD, Serverless, Microservices, Realtime Development, and VAPT. I help startups and enterprises design, build, and scale AI-powered applications, cloud-native architectures, and high-performance software solutions. My expertise spans across full-stack development, AI integration, cloud infrastructure, and DevOps automation. With experience as a Technical Lead, Solution Architect, and Cloud Engineer, I specialize in: ✅ Building scalable & secure full-stack applications ✅ Architecting microservices & serverless systems ✅ AI-powered automation & real-time applications ✅ Cloud DevOps, CI/CD, and VAPT security audits ✅ Full-Stack Development & Cloud Engineering Expertise: - Cloud Solution Architect - Senior Solution Architect - Senior Software Engineer - DevOps Engineer - Technical Project Manager - Realtime Development - Azure Architect - AWS Engineer - AWS Cloud Expert - React.js Developer - Node.js Developer - WordPress Expert - Web App Developer - UI/UX Designer - Full Stack Web Developer - TypeScript - JavaScript - Next.js Developer - MERN Stack Development - Backend Development - Front-End Development - Desktop App Development - Front-end Development - Android App Development - Cross-Platform Mobile Application Development - AI App Development - Web Development - Mobile App Development - Website Customization - API Integration - iOS Development - Full Stack Engineer - Experienced Web Developer ✅ Tools & Technologies I Specialize In: 🔹 Frontend & Web → React.js, Next.js, Vue.js, Angular, Tailwind CSS 🔹 Backend & APIs → Node.js, Express.js, FastAPI, Django, NestJS 🔹 Cloud & DevOps → AWS (Lambda, EC2, S3), Azure, Kubernetes, Docker 🔹 Microservices & Serverless → Event-driven systems, Kafka, RabbitMQ 🔹 Security & VAPT → OWASP, Penetration Testing, API Security, DevSecOps 🔹 AI & Machine Learning → OpenAI, TensorFlow, PyTorch, LangChain ✅ AI Integration & Engineering Expertise: - AI Development - ChatGPT AI Development - AI/ML Development - OpenAI LLM Integration - AI Automation Specialist - AI Automation Engineer - Automation Bots Development - OpenAI GPT-4 Development - Machine Learning Algorithm Expert - Natural Language Processing - Generative AI Expert - LLM Prompt Engineering - AI Model Testing & Optimization - OpenAI Codex - Deep Learning Modeling - AI Automation Engineer - Google AI Dialogflow - Senior AI consultant - Enterprise Software Architect - AI Chatbot Development - AI Application Development - AI Chatbot Integration Expert - AI Model Training Expert - AI Agent Development - AI Chatbot Development Consultant ✅ I also provide Fractional CTO Services to my Clients: - Fractional CTO - Technical Advisor - Technical Consultant - Solution Architect - Enterprise Software Architect - Technical Project Manager - Senior Product Manager - Product Delivery Expert 🚀 𝑳𝒆𝒕’𝒔 𝑩𝒖𝒊𝒍𝒅 𝑺𝒄𝒂𝒍𝒂𝒃𝒍𝒆 & 𝑨𝑰-𝑫𝒓𝒊𝒗𝒆𝒏 𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏𝒔! Need an expert in MERN Stack, Cloud Engineering, Microservices, DevOps, Realtime Development, or AI Integration? I help businesses design scalable, secure, and high-performance applications with cutting-edge cloud and AI solutions. 𝑻𝒉𝒂𝒏𝒌𝒔 𝒂𝒏𝒅 𝑩𝒆𝒔𝒕 𝑹𝒆𝒈𝒂𝒓𝒅𝒔, 𝑨𝒍𝒍𝒂𝒏 𝑷𝒆𝒅𝒓𝒂𝒏𝒂 ------------------------------------------------------------------------------------------------------------------ Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, DevOps Engineer, AWS Expert, Azure Specialist, Cloud Engineer, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, DevOps Engineer, AWS Expert, Azure Specialist, Cloud Engineer, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, DevOps Engineer, AWS Expert, Azure Specialist, Cloud Engineer, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, DevOps Engineer, AWS Expert, Azure Specialist, Cloud Engineer, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer, Senior Solution Architect, Senior AI Architect, DevOps Engineer, AWS Expert, Azure Specialist, Cloud Engineer, Fractional CTO, MERN Stack Developer, ReactJS Developer, NodeJS Developer, Senior AI Engineer.