Hire Vetted Web Application Engineers at Upstaff - Page 5

• Blockchain engineer with 3+ years in Solidity smart contract development, DeFi protocol architecture, and secure decentralized applications using Foundry, Hardhat, and Slither.
• Proficient in full stack Web3 development with React, TypeScript, wagmi, viem, and RainbowKit for seamless wallet integrations and user flows.
• Experienced in building financial and NFT platforms integrating ERC20/ERC721 standards, Chainlink oracles, and IPFS for decentralized data storage.
• Strong background in mathematics and computer science education
• Skilled in rigorous testing methodologies including fuzz, invariant, and stateful testing to ensure smart contract security and protocol reliability.

• Senior Software Developer with 10+ years of experience in full stack development, AI/LLM integration, and cloud native architectures.
• Expertise in React, Next.js, Node.js, Python, TypeScript; architected GPT-4 document intelligence platforms processing 180K+ documents with 32% improved retrieval accuracy.
• Proficient in AI workflow orchestration using LangChain, vector databases, and prompt engineering, optimizing LLM costs by 38% while ensuring 99.8% service availability.
• Strong background in scalable microservices, secure REST APIs, and cloud services (AWS Lambda, ECS, Azure).
• Computer Science degree holder skilled in Agile, SDLC, design patterns, and performance optimization.

Senior Software Engineer with 10+ years of experience building scalable full stack applications using C#, ASP.NET Core, React, Angular, TypeScript, and SQL Server in enterprise, healthcare, and cloud environments. Skilled in integrating AI features (OpenAI API, Azure OpenAI, semantic search, automation), backend services, RESTful APIs, database optimization, secure authentication (JWT, OAuth2, RBAC), and cloud-native CI/CD deployments (Azure DevOps, GitHub Actions, Docker, Kubernetes). Holds a CS degree and excels in system design, performance tuning, agile practices, code reviews, and mentoring cross-functional teams.

• 8+ years designing scalable, high-performance distributed systems using React, Next.js, Node.js, Python, and microservices architectures.
• Expertise in domain-driven design, GraphQL federation, event-driven systems, and cloud-native deployments on Azure and AWS.
• Proven leadership in frontend architecture, including micro-frontends, state orchestration, CI/CD pipelines, and observability with Sentry and Datadog.
• Strong background in secure API gateway design, OAuth2/OIDC, RBAC, and zero-trust inter-service communication.
• Bachelor of Computer Science with extensive experience in containerization (Docker, Kubernetes), infrastructure-as-code, and advanced performance optimization.

• Full-Stack Software Engineer with 3+ years leading end-to-end development of scalable web applications using React.js, Next.js, Node.js, and modern JavaScript (ES6+).
• Proficient in REST API design, database management (MongoDB, MySQL, PostgreSQL, Oracle), and deployment on cloud platforms like Vercel and Linux servers.
• Expertise in system design, responsive UI/UX implementation, performance optimization, and version control with Git/GitHub.
• Founder and Project Lead at a tech initiative delivering client-focused solutions, including optimized photography and portfolio websites with domain and DNS configuration.

• Proficient in Python (Django, Pandas, NumPy) and web technologies (HTML, CSS, JavaScript) with hands-on experience in full-stack development and data analysis.
• Strong background in Computer Science with ongoing postgraduate studies and practical experience in software development methodologies and SDLC.
• Expertise in data processing and automation using Excel Power Query, n8n workflows, and API integrations, improving data accuracy by 20% and reducing reporting time by 30%.
• Skilled in database management with SQL, MongoDB, and ERP systems, supporting optimized business decisions through actionable insights.

• Backend Developer with 2+ years of experience specializing in PHP and Laravel for scalable web applications and backend services.
• Proficient in designing and integrating RESTful APIs, asynchronous processing with AWS SQS, and managing large datasets using MongoDB, DynamoDB, and MySQL.
• Skilled in cloud-based infrastructure and workflows leveraging AWS services to enhance platform stability and performance.
• Experienced in Agile and Scrum methodologies, supporting production deployments, release validation, and continuous system improvements.
• Holds a Bachelor’s Degree in Computer Systems Engineering, combining strong engineering fundamentals with practical software development expertise.

I reduced API response time by 75 percent from 1.2 seconds to 0.3 seconds using FastAPI and Redis caching. I built a payment system handling over 2 million monthly requests with zero downtime for twelve consecutive months. I migrated a fifteen-year-old MFC legacy system to modern C Sharp and .NET, cutting maintenance costs by 60 percent and tripling data processing speed. I also developed cross-platform desktop applications using Qt framework that reached over 10,000 downloads across Windows, macOS, and Linux.

I reduced API response time by 75 percent from 1.2 seconds to 0.3 seconds using FastAPI and Redis caching. I built a payment system handling over 2 million monthly requests with zero downtime for twelve consecutive months. I migrated a fifteen-year-old MFC legacy system to modern C Sharp and .NET, cutting maintenance costs by 60 percent and tripling data processing speed. I also developed cross-platform desktop applications using Qt framework that reached over 10,000 downloads across Windows, macOS, and Linux.

• 6+ years of experience delivering scalable web and cross-platform mobile applications using Vue.js, React, TypeScript, Node.js, and Spring Boot across EU and US markets.
• Proven expertise in modern front-end frameworks (Vue, Nuxt, React) and back-end microservices architecture, with strong skills in event-driven systems and RESTful API design.
• Led migration projects improving platform performance by 30-40%, including decoupling legacy systems and transitioning from Vue to React for SaaS platforms.
• Hands-on experience with testing frameworks (Jest, Vitest, Playwright), CI/CD pipelines on Azure and AWS, and component-driven development using Storybook.

• Senior Frontend Engineer with 9+ years of expertise in React, TypeScript, Next.js, and scalable frontend architectures including Feature-Sliced Design and SSR/SSG/ISR.
• Fintech, CRM, AI dashboards, optimizing performance and improving key business metrics.
• Strong skills in state management (Zustand, Redux, RTK Query), design systems (Material UI, AntD, shadcn/ui), and modern tooling (Vite, Webpack, Docker, CI/CD).
• Experienced in complex domain-driven UI systems, dynamic forms with typed validation, and multi-channel notification workflows, delivering maintainable and scalable solutions.
• Adept in Agile/Scrum methodologies, cross-functional collaboration, and mentoring within distributed teams.

• Senior full-stack engineer with 6+ years of experience delivering scalable B2B platforms using React, Node.js, and SQL (PostgreSQL/MySQL).
• Expertise in designing and optimizing REST and GraphQL APIs with OAuth 2.0 authentication, improving backend response times by up to 40%.
• Proficient in deploying micro-applications on Google Cloud Platform (Cloud Run, Cloud SQL) ensuring 99.9% uptime and automated scaling.
• Strong background in computer science with Master’s and Bachelor’s degrees from University of Belgrade.
• Skilled in CI/CD automation, webhook integrations, and resolving critical production issues, reducing release cycles by 30% and support tickets by 25%.

• Expertise in designing upgradeable smart contracts using the diamond pattern and UUPS proxies, managing 180k+ NFTs, and securing $2M+ in tokens with gas-optimized staking and vesting contracts.
• Proficient in Go, TypeScript, and Solidity, developing backend services, TypeScript SDKs, and cross-chain token bridges (Polygon, Ethereum, Base, Solana).
• Skilled in integrating Uniswap V3 oracles, building metatransaction flows, and automating multisig treasury operations with Node CLI tooling.
• Strong background in blockchain security, performing audits, vulnerability analysis with MythX and Slither, and implementing best practices before mainnet releases.

• AI Automation Engineer and Full Stack Developer with 5+ years delivering 50+ AI-powered SaaS platforms and automation pipelines for international clients.
• Expertise in Python, JavaScript (React.js, Vue.js, Next.js, Node.js), FastAPI, and cloud deployment on AWS, Azure, DigitalOcean with CI/CD and Infrastructure as Code.
• Proficient in integrating OpenAI API, LangChain, LangGraph for multi-agent intelligent workflows and building scalable RESTful APIs and microservices.
• Skilled in automation tools n8n, Zapier, and developing AI voice/caller agents, WhatsApp and Telegram bots to optimize business operations and reduce manual effort by up to 80%.

• Software Engineer with 4+ years of experience specializing in backend systems, distributed platforms, and blockchain products using Go, TypeScript, Node.js, AWS, and Solidity.
• Proven expertise in building event-driven architectures, serverless workflows, and production smart contracts with a focus on clean architecture and high throughput, including migrating services to Go .
• Hands-on experience developing DeFi platforms, integrating Uniswap SDK, and managing secure multi-wallet infrastructures for scalable blockchain applications.
• Strong foundation in Computer Science with a BSc degree and MSc in Information Technology, complemented by specialized bootcamps in Solidity and Solana development.

• Software engineer with 5+ years specializing in full-stack Web3 applications, DeFi protocols, and scalable cloud infrastructure.
• Expertise in React, Node.js, TypeScript, Ethers.js, and AWS, demonstrated by architecting NFT marketplaces supporting ERC-721/1155 standards and integrating complex DeFi functionalities.
• Proficient in CI/CD pipeline development using AWS CodePipeline.
• Strong background in computer science with a Bachelor of Computer Application degree and hands-on experience in testing frameworks like Jest and React Testing Library to ensure code reliability.
• Skilled in Atomic Design architecture, RESTful API development, and cloud deployment, and user-centric blockchain applications.

• Senior Java Developer with 9+ years of expertise in Java (up to v21), specializing in scalable, modular backend architectures for cybersecurity, banking, and automotive sectors.
• Certified Adobe Experience Manager Sites Developer with advanced skills in AEM as a Cloud Service, Spring Boot, RESTful APIs, OAuth 2.0, and automated data migration using Groovy.
• Proven ability to design secure OAuth 2.0 authentication services, integrate enterprise CRM systems, and implement observability with Elasticsearch and Kibana.
• Experienced in Agile Scrum environments, CI/CD pipelines (Jenkins, Adobe Cloud Manager), and code quality assurance using SonarQube and JUnit testing frameworks.

• Backend and Platform Engineer with 7+ years of experience in fintech, cloud platforms, and event ticketing, specializing in scalable payment systems and compliance workflows (KYC/KYB/KYT).
• Proficient in Go, Python, JavaScript, Kafka, RabbitMQ, and AWS services, with expertise in CI/CD automation, containerization (Docker, Kubernetes), and Linux infrastructure.
• Led critical migrations including Linux VM to Kubernetes, and Jenkins to GitLab CI, achieving zero downtime and improved deployment efficiency.
• Developed multi-tenant SaaS products reducing client go-live time from 1 year to 2 months, and implemented idempotent payment processing to prevent double spending.

Developed and deployed blockchain and web3 applications involving smart contracts, wallet integrations, token management, and decentralized features. Built scalable frontend and backend systems using React.js, Node.js, and MongoDB. Worked on optimizing application performance, improving user experience, and integrating blockchain functionality securely with modern web technologies.

• Senior Software Engineer with 3+ years specializing in full-stack development and blockchain systems across EVM, Solana, and Bitcoin ecosystems.
• Proficient in JavaScript, TypeScript, Python, Rust, Go, and Solidity; experienced with React.js, Next.js, Node.js, REST APIs, and microservices architecture.
• Led smart contract development and backend automation for decentralized applications, including multi-chain DeFi platforms and NFT systems.
• Skilled in blockchain integrations, wallet connectivity, on-chain data processing, and decentralized storage using IPFS.
• Holds a B.E. in Computer Science and a P.G. Diploma in Fintech & Blockchain; awarded 1st place at BlockBash 2024 ICP Hackathon.

• Web3 Engineer with 2+ year experience in decentralized finance (DeFi) projects, specializing in scalable backend development and RESTful API design using Typescript, Golang and Solidity.
• Proficient in blockchain architecture, Web3 technologies, and smart contract development, with hands-on experience in Docker, MySQL, Linux, Git, and GitLab.
• Demonstrated ability to design, implement, test, and monitor backend solutions in fast-paced environments, contributing to cross-functional team projects.
• Experience in software development lifecycle (SDLC) practices, code quality assurance, and integration of new features enhancing end-user flows.

• AI/ML Engineer with 3.5 years of experience specializing in Python, FastAPI, PyTorch, TensorFlow, and OpenCV for developing real-time AI solutions including video avatars, hotel monitoring, and social media automation.
• Proficient in asynchronous programming, API integration, CI/CD pipelines (GitHub Actions), and cloud deployment on AWS, ensuring scalable and efficient back-end systems.
• Expertise in LLM prompt chain algorithms, multi-source data scraping, and AI-driven analytics for business intelligence and sales optimization.
• Holds a Bachelor’s degree in Computer Science and certified in Practical Deep Learning with PyTorch and SQL for Data Science

• Full-Stack Developer with 3 years of experience specializing in Python (FastAPI, Flask), Java (Spring Boot with Hibernate), and modern JavaScript frameworks (React, Next.js), delivering scalable web applications and microservices.
• Proficient in API integrations, real-time communication (WebSockets, SSE), and cloud-native development using Docker, AWS, and CI/CD pipelines with GitHub Actions.
• Hands-on expertise in RDBMS (PostgreSQL, MySQL), NoSQL (MongoDB, Redis), and advanced front-end state management (Redux, Redux-Saga, RTK Query) with UI/UX optimization and performance tuning.

• 3.5 years of full-stack development experience specializing in Python (FastAPI, Django, DRF, Flask) and React.js with TypeScript for frontend.
• Proficient in asynchronous programming, OOP principles, unit testing, CI/CD pipelines (GitHub Actions), and Agile methodologies (Scrum, Kanban).
• Developed AI-integrated web applications in legal and healthcare domains, handling complex file processing and AI-driven features.
• Skilled in RDBMS (PostgreSQL, MySQL), NoSQL (Redis, Firestore), Docker, cloud platforms (AWS, GCP), and technical documentation.
• Experienced in SDLC from architecture to deployment, code reviews, refactoring, and collaborative team environments.

• 5.5+ years engineering high-load B2B/B2C platforms in AdTech, fintech, blockchain, and real-time communications, specializing in backend and full stack development.
• Expertise in Python, JavaScript/TypeScript, Django, React, PostgreSQL, Redis, Docker, AWS, and Azure, with proven impact: 109k query reduction, 92% latency cut, and 60 FPS UI performance.
• Skilled in SDLC ownership, architectural refactoring, multi-tenant SSO, microservices, and CI/CD pipelines using GitHub Actions.

• Back-End Developer and DevOps Engineer with 4.5 years of experience in designing and developing scalable backend systems using Python (Django, DRF, FastAPI) and deploying on AWS with Docker, Kubernetes, and Helm.
• Proficient in implementing secure, role-based access control and optimizing database schemas across RDBMS (PostgreSQL, MySQL) and NoSQL (Elasticsearch, Redis) environments.
• Experienced in Agile methodologies, test-driven development, and applying design patterns (Factory, Strategy) to maintain clean, modular codebases in healthcare and government domains.

• AI/ML Engineer and Backend Developer with 4 years of experience in designing RAG-based chatbots, AI agents, and automated workflows using Python, FastAPI, Flask, and SQL/NoSQL databases.
• Expertise in integrating LLMs (GPT, Claude, LLaMa) with vector search technologies (Pinecone, ChromaDB) and enterprise tools like Salesforce and Google Workspace for real-time communication and lead generation.
• Proficient in software architecture design, prompt engineering, and building scalable AI systems with robust error handling and workflow automation using n8n and Zapier.

• Engineer with 6+ years leading backend development and architecture of AI-driven microservice platforms in fintech, e-commerce, and digital content.
• Expert in Python, FastAPI, Django, event sourcing, and cloud-native solutions (AWS, GCP, Kubernetes), delivering scalable, real-time data processing systems.
• Proficient in SQL/NoSQL databases, messaging queues (Kafka, RabbitMQ), containerization (Docker), CI/CD pipelines, and API integrations.
• Skilled in agile methodologies, code quality enforcement, mentoring, and end-to-end project delivery of complex AI and fintech applications.

• Full-Stack Developer with 3 years of experience specializing in Blockchain, AI, and Healthcare AI domains, delivering scalable, secure, and modular web and mobile applications.
• Proficient in Python, JavaScript/TypeScript, React, Next.js, FastAPI, Django, PostgreSQL, Docker, and cloud infrastructure (GCP), with strong expertise in asynchronous programming and software architecture design.
• Implemented AI-driven solutions including Retrieval-Augmented Generation pipelines, vector database semantic search, and real-time chatbots integrating LangChain and OpenAI technologies.

• AI/ML Engineer with 3 years of experience delivering production-ready machine learning systems, including real-time generative AI avatars and multi-agent orchestration frameworks.
• Proficient in Python, PyTorch, FastAPI, and LLM ecosystems (OpenAI, LLaMA, LangChain), with strong expertise in deploying scalable AI solutions using Docker and AWS cloud services.
• Skilled in full ML lifecycle: data engineering, model training, deployment, monitoring, and optimization, demonstrated by building an AI-driven ad bid price optimization model and modular workflow systems.

• Full-stack engineer with 7+ years in PHP/WordPress and 5+ years in JavaScript/TypeScript;
• Built data platforms using Python, SQL, ETL pipelines (Airflow, PySpark), and AWS;
• Developed custom WordPress plugins, REST APIs, and data-driven features (tables, reports, analytics);
• Skilled SQL and database design (PostgreSQL/MySQL), including query optimization;
• Experience integrating AI/LLM features into data products and analytics workflows.

• Senior Full-Stack Engineer with 9+ years in FinTech and E-commerce, proficient in React, Node.js, NestJS, PHP, Java, and .NET Core.
• Expertise in building high-volume transactional systems, fraud detection microservices, and credit onboarding platforms with 99.99% uptime and sub-120ms response times.
• Skilled in Agile delivery, CI/CD pipelines, and cloud-native DevOps using Docker, Kubernetes, AWS, and Azure.
• Strong background in regulatory compliance and platform modernization, achieving 85% test coverage and 40ms faster response times.
• Computer Science graduate with proven ability to lead cross-border teams and deliver scalable, secure, and observable APIs and CMS solutions.