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OSCP & CREST-certified Penetration Tester helping SaaS companies, startups, e-commerce platforms, and enterprise teams find real, exploitable security weaknesses before attackers do. I provide manual-first penetration testing for Web Applications, APIs, Mobile Apps, Networks, Active Directory environments, Infrastructure, and Thick Client/Desktop Applications. My focus is not just finding vulnerabilities, but validating real-world exploitability, explaining business impact, and giving your developers clear remediation guidance they can actually apply. 🔎 Core services I provide: • Web Application Penetration Testing • API Security Testing • Mobile Application Penetration Testing for Android and iOS • External Network Penetration Testing • Internal Network & Active Directory Security Assessment • Thick Client / Windows Desktop Application Testing • OWASP Top 10 & OWASP WSTG-Based Security Testing • Vulnerability Assessment & Manual Validation • OSINT & External Attack Surface Assessment • Security Retesting & Remediation Validation • SOC 2, ISO 27001, PCI DSS, Amazon SP-API, and compliance-oriented pentest reports 📄 What you receive: • A professional penetration testing report • Clear proof-of-concept evidence and screenshots • Technical explanation of each vulnerability • Business impact written in simple, practical language • Severity rating and CVSS scoring where applicable • Step-by-step remediation guidance for developers • Retest results after your team applies fixes • Executive summary suitable for management, compliance, vendor review, and internal audit ⚡ My testing approach: I perform Black Box and Grey Box penetration testing depending on your project requirements. I use a manual-first methodology supported by professional tools such as Burp Suite Pro, but I do not rely only on automated scanners. The goal is to identify security issues that matter in real attack scenarios, including authentication flaws, authorization bypasses, SQL Injection, IDOR, access control issues, business logic vulnerabilities, API security weaknesses, injection flaws, misconfigurations, and sensitive data exposure. 🎯 Best fit if you need: • A security test before launching a product or major feature • A web application, API, mobile app, network, or infrastructure assessment • A compliance-ready report for SOC 2, ISO 27001, PCI DSS, vendor review, or investor due diligence • Manual security testing focused on real exploitability • Clear communication with practical remediation advice • Reliable retesting after fixes are completed 🏆 Certifications and experience: • OSCP • OSEP • OSWP • CREST CPSA • Top Rated in Information Security / IT Compliance • Ranked in the Top 50 in multiple bug bounty programs • Completed 500+ penetration tests and security assessments • Available across different time zones • Open to one-time assessments and long-term security engagements ✅ Need a professional penetration test or vulnerability assessment for your web application, API, mobile app, network, or infrastructure? 📩 Send me a message, and I will help you define the right scope, testing approach, timeline, and deliverables for your security goals.

I am a Full Stack Web & Mobile App Developer with expertise in Web Development, iOS & Android App Development (Top 3%), maintaining 100% Client Satisfaction on Upwork and successfully delivering hundreds of projects across industries. I am a Top-Rated Plus Mobile App Developer specializing in Flutter, React Native, iOS (Swift), Android (Kotlin) and Full-Stack Application Development. I build AI-powered mobile apps, real-time video streaming platforms, SaaS products, MVPs and on-demand service applications with scalable backend architectures using Node.js, NestJS, Laravel and Firebase. I have had the opportunity to work with numerous startups, scale-ups and enterprises, helping them design, develop, launch and scale high-performance mobile and web applications that work flawlessly across devices. ✅ I Can Help You With: - Mobile App Development with Web Admin Panel - MVP Development & SaaS Application Development - API Development & Third-Party Integrations - Node.js / NestJS Backend for Mobile & Web Apps - Laravel / PHP Backend Development - Firebase Integration (Auth, Firestore, Cloud Functions) - Payment Gateway Integration (Stripe, Razorpay, PayPal) - Real-Time Chat, Notifications & WebSocket Integration 💡 Having Expertise In: - AI-Powered Mobile Applications - Real-Time Video Streaming Apps - Live Streaming & Video Sharing Platforms - E-Learning & EdTech Applications - E-Commerce & Marketplace Apps - On-Demand Service Apps (Taxi, Food, Delivery, Booking) - Chat & Social Networking Apps - SaaS & Subscription-Based Platforms - Gamified Mobile Applications - AR/VR Mobile App Development - IoT & BLE-Based Mobile Applications 🎯Key Milestones: 🚀 Rewarded as 🏆 𝗧𝗢𝗣 𝗥𝗔𝗧𝗘𝗗 𝗣𝗟𝗨𝗦 🏆 by Upwork (𝗧𝗼𝗽 𝟯%) 🚀 7000+ personal hours on Upwork and still counting 🚀 100000+ agency hours on Upwork and still counting 🚀 100% Job Success (Client Satisfaction Ratio) 🚀 500+ jobs completed successfully as an Agency 🎯 Checkout my portfolio of apps on Upwork: Over the past decade, I have honed my skills in developing a diverse array of iPhone and Android applications Development ✅ Health and Fitness Apps ✅ GPS/ Geo Location Apps ✅ Trade Apps ✅ Homeowner/Contractor App ✅ Artificial Intelligence based Apps ✅ Bluetooth / BLE Integration Apps ✅ Food Delivery Apps ✅ Nutrition Planning Apps ✅ Restaurant Search Apps ✅ Salon Booking Apps ✅ Gym Booking Apps ✅ Taxi Apps ✅ AI Powered Apps ✅ E-commerce Apps ✅ Dating and TikTok Style Apps ✅ Video Streaming, Voice Calling, Chat and Messaging Apps ✅ Real Estate Apps ✅ Driver Instructor Finding Application ✅ Hotel and Travel Booking Apps ✅ E-Learning Mobile Application ✅ Wellness & Meditation Application ✅ NDI's Industry Applications 🎯 Areas of Expertise ◉ Mobile App Development: Swift, Objective C, Kotlin, Java, Jetpack ◉ Cross-Platform App Development: Flutter (Dart), React Native ◉ Backend Development: Node JS, Nest JS, Laravel, PHP, Express ◉ Frontend Development: React JS, Next JS, Angular, HTML5, CSS3 ◉ API Development & Integrations: REST APIs, AWS Lambda, API Gateway ◉ Databases & Cloud Storage: MySQL, MongoDB, Firebase, DynamoDB ◉ Real-Time App Features: Socket IO, Firebase Real Time Database, Twilio ◉ Payment Gateway Integration: Stripe, Razorpay, PayPal, Braintree ◉ Maps & Location Services: Google Maps, Apple Map Kit, GPS Tracking ◉ Version Control & Collaboration: GitHub, Bitbucket, GitLab I specialize in no-code/low-code development and AI integrations, allowing you to launch faster while keeping costs low without compromising quality. Additional Services that i am offering: - 6 Months Free Maintenance once the apps goes live on apple store and Google play store - Ownership/iP rights from the day one uploaded on the Client Github - Regular Updates & Scrum meetings. - Following Agile Scrum Methodology from day one - Strictly adhering to the Apple Guidelines and Google Guidelines. - Taking Complete responsibility of Deployment on both Apple store and Google Play store. I specialize in no-code/low-code development and AI integrations, allowing you to launch faster while keeping costs low without compromising quality. I work with tools like Bubble, FlutterFlow, Webflow and integrate powerful AI solutions using Claude, GPT and OpenAI APIs to build smart, automated systems. 🔹 What I Do - Full Stack Web & Mobile App Development - No-Code / Low-Code Development (Bubble, FlutterFlow, Webflow) - AI App Development & Integration (Claude AI, GPT-4/5, OpenAI API, Chatbots, Automation) - SaaS Application Development (Subscription Models, Multi-Tenant Systems) - API Integration (Payment gateways, third-party services) - Dashboard & Admin Panel Development - Workflow Automation (Zapier, Make, AI Automation Systems)) - UI/UX Design (Figma) 👉 Let’s start with a FREE 15–30 minute consultation to discuss your project and define the best approach. Contact us today to discuss your project requirements.

I find the vulnerabilities in your web apps, APIs, and networks before attackers do, then hand your team a clear, reproducible penetration testing report they can act on. GXPN and GCIH certified. Top Rated on Upwork with 100% Job Success across web application, API, and network security engagements. No scanner dump and no jargon wall. Every finding comes with a severity rating (CVSS), working proof of concept, and a concrete fix your developers can ship. What I test: - Web application penetration testing (OWASP Top 10, PTES, NIST) - API security testing (REST, GraphQL, auth/OAuth, IDOR, broken access control) - SaaS and multi-tenant assessments (Supabase / Firebase data-isolation testing) - Network and external perimeter penetration testing - Source code / secure code review How I work: authorized testing only, on systems you own or have permission to test. Everything is documented over Upwork so you get a written record of every finding, not a verbal hand-wave. I retest after you patch to confirm the holes are actually closed. Credentials: GXPN (GIAC Advanced Penetration Tester & Exploit Researcher), GCIH (GIAC Certified Incident Handler), SANS CTF winner, and an active national/international CTF competitor (web, reverse, crypto, forensics). I also handle WordPress malware removal and incident response. See my Project Catalog for a fixed-price option.

𝗧𝗼𝗽 𝗥𝗮𝘁𝗲𝗱 𝗔𝗜 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿 & 𝗙𝘂𝗹𝗹-𝗦𝘁𝗮𝗰𝗸 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿 | 8+ 𝗬𝗲𝗮𝗿𝘀 | 𝟭% 𝗼𝗳 𝗨𝗽𝘄𝗼𝗿𝗸 | 𝟭𝟬𝟬% 𝗝𝗼𝗯 𝗦𝘂𝗰𝗰𝗲𝘀𝘀. ✅ $300K+ Total earnings ✅8+ Years experience as Fullstack Developer ✅ 80+ Projects Completed. ✅Top Rated Plus. ✅ 100% Job Success Rate. ✅ AWS certified ✅ Python certified ✅50hrs/week available ✅ 4+ AI/ML Integrations 🔴 I am in the 𝗧𝗼𝗽 𝟭% overall on Upwork. 🔴 I am in the 𝗧𝗼𝗽 𝟰% overall on Stack Overflow. 𝐀𝐈 𝐀𝐠𝐞𝐧𝐭 / 𝐕𝐨𝐢𝐜𝐞 𝐀𝐠𝐞𝐧𝐭𝐬: 𝐂𝐫𝐞𝐰𝐀𝐈 / 𝐀𝐮𝐭𝐨𝐆𝐞𝐧 / 𝐀𝐦𝐚𝐳𝐨𝐧 𝐏𝐨𝐥𝐥𝐲 / 𝐃𝐞𝐞𝐩𝐠𝐫𝐚𝐦 / 𝐑𝐚𝐬𝐚 𝐀𝐈 / 𝐑𝐢𝐯𝐞𝐫𝐬𝐢𝐝𝐞 𝐒𝐃𝐊 / 𝐀𝐳𝐮𝐫𝐞 𝐀𝐈 𝐒𝐩𝐞𝐞𝐜𝐡/𝐋𝐋𝐌 𝐅𝐢𝐧𝐞𝐭𝐮𝐧𝐢𝐧𝐠: 𝐔𝐬𝐢𝐧𝐠 𝐏𝐄𝐅𝐓 / 𝐋𝐨𝐑𝐀 / 𝐐𝐋𝐨𝐑𝐀 / 𝐑𝐋𝐇𝐅 / 𝐃𝐏𝐎 / 𝐒𝐅𝐓 𝐰𝐢𝐭𝐡 𝐔𝐧𝐬𝐥𝐨𝐭𝐡 / 𝐀𝐱𝐨𝐥𝐨𝐭𝐥 / 𝐇𝐮𝐠𝐠𝐢𝐧𝐠𝐅𝐚𝐜𝐞 𝐀𝐮𝐭𝐨𝐓𝐫𝐚𝐢𝐧 / 𝐒𝐚𝐠𝐞𝐌𝐚𝐤𝐞𝐫 𝐓𝐫𝐚𝐢𝐧𝐢𝐧𝐠/𝐎𝐩𝐞𝐧-𝐒𝐨𝐮𝐫𝐜𝐞 𝐋𝐋𝐌𝐬: 𝐋𝐋𝐀𝐌𝐀 𝟑 / 𝐌𝐢𝐬𝐭𝐫𝐚𝐥 𝟕𝐁 / 𝐌𝐢𝐱𝐭𝐫𝐚𝐥 𝟖𝐱𝟕𝐁 / 𝐅𝐚𝐥𝐜𝐨𝐧 / 𝐆𝐞𝐦𝐦𝐚 / 𝐁𝐥𝐨𝐨𝐦 / 𝐎𝐫𝐜𝐚 𝐌𝐢𝐧𝐢 / 𝐆𝐮𝐚𝐧𝐚𝐜𝐨/𝐅𝐚𝐬𝐭 𝐈𝐧𝐟𝐞𝐫𝐞𝐧𝐜𝐞: 𝐯𝐋𝐋𝐌 / 𝐓𝐆𝐈 / 𝐓𝐞𝐧𝐬𝐨𝐫𝐑𝐓-𝐋𝐋𝐌 / 𝐒𝐊𝐏𝐢𝐥𝐨𝐭/𝐏𝐫𝐨𝐦𝐩𝐭 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠: 𝐌𝐮𝐥𝐭𝐢-𝐭𝐮𝐫𝐧 / 𝐅𝐞𝐰-𝐬𝐡𝐨𝐭 / 𝐙𝐞𝐫𝐨-𝐬𝐡𝐨𝐭 / 𝐑𝐀𝐆-𝐁𝐚𝐬𝐞𝐝 / 𝐏𝐫𝐨𝐠𝐫𝐚𝐦𝐦𝐚𝐛𝐥𝐞 𝐏𝐢𝐩𝐞𝐥𝐢𝐧𝐞𝐬/𝐐𝐮𝐚𝐧𝐭𝐢𝐳𝐚𝐭𝐢𝐨𝐧: 𝐀𝐖𝐐 / 𝐆𝐏𝐓𝐐 / 𝐆𝐆𝐔𝐅 / 𝐆𝐆𝐌𝐋 / 𝐐𝐋𝐎𝐑𝐀 / 𝐏𝐓𝐐 / 𝐃𝐐/𝐑𝐀𝐆 𝐒𝐲𝐬𝐭𝐞𝐦𝐬 & 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞𝐬: 𝐋𝐚𝐧𝐠𝐂𝐡𝐚𝐢𝐧 / 𝐋𝐥𝐚𝐦𝐚𝐈𝐧𝐝𝐞𝐱 / 𝐂𝐡𝐫𝐨𝐦𝐚 / 𝐅𝐀𝐈𝐒𝐒 / 𝐏𝐢𝐧𝐞𝐜𝐨𝐧𝐞 / 𝐐𝐝𝐫𝐚𝐧𝐭 / 𝐖𝐞𝐚𝐯𝐢𝐚𝐭𝐞 / 𝐌𝐢𝐥𝐯𝐮𝐬 Greetings! I am Atul Kumar, a seasoned developer with over 8+ years of experience in web application and software development. Working with LLMs for the past 8+ years and have good expertise in AI Agents development using langchain, LlamaIndex, and LLMs like Claude, GPT4o, Amazon Bedrock, Ollama 🔹 AI Agents / Voice Agents: CrewAI, AutoGen, Amazon Polly, Deepgram, Rasa AI 🔹 LLM Fine-tuning: PEFT, LoRA, QLoRA, RLHF, DPO with Unsloth, Axolotl, HuggingFace AutoTrain 🔹 Open-Source LLMs: LLaMA 3, Mistral 7B, Mixtral 8×7B, Falcon, Gemma 🔹 Inference Optimization: vLLM, TGI, TensorRT-LLM 🔹 Prompt Engineering: Multi-turn, Few-shot, Zero-shot, RAG-based prompts 🔹 Quantization: AWQ, GPTQ, GGUF, GGML 🔹 RAG Systems: LangChain, LlamaIndex, ChromaDB, FAISS, Pinecone, Qdrant 🔹 Data Pipeline: Synthetic dataset generation, LLM evaluation frameworks 🔹 LLM Deployment: AWS Sagemaker, RunPod, GCP AI Platform, Vercel AI SDK 🖥️ 𝗕𝗮𝗰𝗸𝗲𝗻𝗱 𝗦𝗸𝗶𝗹𝗹𝘀: 🔹 Proficient in Node.js, Express.js, Python, Django, Flask, AWS Lambda for backend API. 🔹 Experienced with relational & NoSQL databases: MySQL, PostgreSQL, MongoDB, Firebase, Firestore. 🔹 Skilled in Python FastAPI, REST API, GraphQL API development, and database schema design. 🔹 Knowledgeable in Redis, Docker, Kubernetes, AWS EC2, S3, Nginx for scalable infrastructure. 🔹 Experienced with Nest.js for enterprise-grade server-side applications. 🔹 LangChain, LangServe, LangSmith, HuggingFace, Transformers for AI/LLM integrations. 🔹 Vector Databases: Chroma, FAISS, Pinecone, Qdrant for RAG pipelines. 🔹 Low-code AI tools: Flowise AI, LangFlow, StackAI for rapid prototyping. 🔹 Familiar with Celery task queues, testing frameworks (Pytest, Unittest), and automation tools like Selenium. 🌐 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝗦𝗸𝗶𝗹𝗹𝘀: 🔹 Proficient in TypeScript, Redux Toolkit, Tailwind CSS with Next.js for high-performance frontends. 🔹 Skilled in building Progressive Web Apps (PWA) and Single Page Applications (SPA). 🔹 Expert in Vue.js, Nuxt.js, React.js, Next.js, HTML5, CSS3, React Native for responsive and cross-platform UIs. 🛠️ 𝗧𝗼𝗼𝗹𝘀 & 𝗧𝗲𝗰𝗵𝗻𝗼𝗹𝗼𝗴𝗶𝗲𝘀: 🔹 Skilled in Python ML libraries: Scikit-learn, Numpy, Pandas, Matplotlib, Seaborn. 🔹 Familiar with OpenAI APIs, Whisper, GPT models, ChatGPT integration, and AI chatbot deployment. 🔹 Experienced with AWS (Lambda, S3, EC2, Sagemaker), Git/GitHub, and Linux environments (Ubuntu, CentOS). 🌟 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 𝗔𝗜 & 𝗟𝗟𝗠 𝗦𝗸𝗶𝗹𝗹𝘀: 🔹 AI Agents / Voice Assistants: CrewAI, AutoGen, Amazon Polly, Deepgram, Rasa AI. 🔹 Open-Source LLMs: LLaMA 3, Mistral 7B, Mixtral 8×7B, Falcon, Gemma. 🔹 Inference Optimization: vLLM, TGI, TensorRT-LLM for high-speed deployments. 🔹 Prompt Engineering: Multi-turn, Few-shot, Zero-shot, RAG-based prompts. 🔹 Quantization: AWQ, GPTQ, GGUF, GGML for efficient LLM deployment. 🔹 LLM Fine-tuning: PEFT, LoRA, QLoRA, RLHF, DPO with Unsloth, Axolotl, H My expertise spans both frontend and backend technologies, as well as a variety of tools and additional skills that enable me to deliver comprehensive solutions. I am dedicated to providing high-quality, efficient solutions that cater to the unique needs of each project. My diverse skill set allows me to approach challenges from multiple angles, ensuring robust and innovative solutions. Warm regards, Atul Kumar

I’m an eWPTX-certified Cybersecurity Consultant with a Bachelor’s degree in Cybersecurity and over 10 years of hands-on experience in application security, helping organisations identify vulnerabilities across web applications, mobile apps, APIs, cloud environments, and IoT/embedded systems. I help companies identify real vulnerabilities in their systems and understand how they can be exploited, not just theoretically, but in practice. My focus is on manual, attacker-driven testing aligned with OWASP Top 10 and beyond, with clear, actionable outcomes for your team. I’ve worked with SaaS platforms, multi-tenant systems, and applications handling sensitive data, including projects aligned with HIPAA and FDA requirements. What I can help you with: * Web and API penetration testing * Mobile application testing (iOS, Android) * Network penetration testing * Cloud and backend security assessments * IoT and embedded device penetration testing * Embedded systems security audits My approach: * Manual testing, not just automated scans * Focus on real attack paths and impact * Clear communication throughout the process What you get: * Professional report with severity (CVSS), evidence, and reproduction steps * Practical remediation guidance your developers can use * Executive summary for non-technical stakeholders Technologies and platforms I have experience with (including, but not limited to): * Frontend: React, Next.js, TypeScript, Tailwind CSS * Backend: Node.js, Express, FastAPI, Laravel (PHP) * Databases: PostgreSQL, Supabase, Firebase, MongoDB * Cloud & BaaS: AWS, Supabase, Firebase, Vercel, Cloudflare * APIs: REST, GraphQL, PostgREST * Auth & Security: JWT, OAuth, RBAC, Row Level Security (RLS) * Payments: Stripe (Checkout, webhooks, subscriptions) * Mobile: Android, iOS (dynamic analysis with Frida, Objection) * Embedded & IoT: Microcontrollers, device logic analysis, firmware interaction * DevOps & Infra: Docker, CI/CD pipelines, GitHub Actions * AI integrations: RAG-based systems, prompt injection testing, data leakage analysis I’m easy to work with, responsive, and focused on delivering results that actually improve your security.

Hi, I'm Dmytro. I'm a Front End developer with more than 8 years of experience building web and mobile applications for startups, product companies, and growing businesses. As a Front End developer, I've worked on MVPs, SaaS platforms, e-commerce products, internal business tools, and customer-facing applications used by thousands of users. My primary focus as a Front End developer is creating fast, responsive, and user-friendly applications using modern JavaScript technologies. I enjoy transforming complex requirements into clean, maintainable solutions that provide real value to users and businesses. Throughout my career as a Front End developer, I've worked closely with designers, product managers, backend engineers, and business stakeholders to deliver products that are both technically solid and enjoyable to use. I believe a successful Front End developer should understand not only the code but also the goals behind the product. Technologies I work with As a Front End developer, my main stack includes: React Next.js TypeScript JavaScript React Native Angular Vue.js HTML5 CSS3 Tailwind CSS Material UI (MUI) SCSS Webpack Vite Node.js Over the years, I've helped companies hire a reliable Front End developer who can contribute quickly, improve existing codebases, and build new features with confidence. What I can help with As a Front End developer, I can help with: Building modern web applications from scratch Developing scalable React and Next.js applications Creating reusable component libraries Design system implementation Responsive and mobile-first development Performance optimization Server-Side Rendering (SSR) Progressive Web Apps (PWA) API integration Frontend architecture React Native mobile applications Refactoring legacy projects Bug fixing and maintenance Many clients choose me as a Front End developer because I can quickly understand business requirements and translate them into practical solutions. When companies need a Front End developer who can take ownership of a feature from planning to production, I can provide that support. I've worked as a Front End developer on both small startup projects and large-scale applications. My experience as a Front End developer allows me to adapt to different team structures, coding standards, and development processes. Although my primary role is a Front End developer, I also have experience with backend development. This broader perspective helps me become a more effective Front End developer because I understand how frontend systems interact with APIs, databases, and cloud infrastructure. I've worked with: PostgreSQL MongoDB MySQL Firebase Firestore Supabase AWS Node.js Python PHP This experience allows me to work effectively with backend teams and contribute as a Front End developer who understands the complete product lifecycle. How I work I believe a great Front End developer should focus on more than writing code. A Front End developer should understand user experience, accessibility, performance, maintainability, and business objectives. As a Front End developer, I value clear communication, ownership, and attention to detail. Every Front End developer should be able to balance technical excellence with practical business needs, and that's the approach I bring to every project. I've also contributed as a Front End developer in areas such as: Code reviews Technical planning Frontend architecture Git workflows CI/CD pipelines Agile development Team collaboration Mentoring junior developers Whether you need a Front End developer for a short-term project, a Front End developer for long-term collaboration, or a Front End developer to strengthen your current engineering team, I can help. My goal as a Front End developer is to build products that users enjoy using and that businesses can confidently grow over time. Companies often look for a Front End developer who can join an existing team and become productive quickly. Others need a Front End developer to help launch a new product or modernize an existing application. In both cases, I focus on delivering reliable, maintainable, and scalable solutions. If you're looking for a Front End developer with strong React expertise, modern frontend experience, and a practical approach to product development, I'd be happy to discuss your project. Best regards, Dmytro