Hire the Best API Developers
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Vadim P.

Barcelona, Spain

$45/hr
5.0
22 jobs

Need someone who can build, stabilize and scale your Android product? You just found him ๐Ÿค ๐Ÿ“Š 12+ years in mobile delivery ๐Ÿ“Š 20+ Android-focused projects ๐Ÿ“Š 10+ years supporting regulated and business-critical products ๐Ÿ“Š Experience with compliance-ready apps, secure payments, backend-heavy systems and Software Development I help companies create secure, maintainable, high-performance apps for Healthcare, FinTech and consumer products. Core Expertise ๐Ÿ”น Native Android engineering with modern architecture and Software Design ๐Ÿ”น Kotlin-first development with maintainability in mind ๐Ÿ”น Legacy modernization from Java to Kotlin ๐Ÿ”น Secure integrations, performance tuning, release stability ๐Ÿ”น Product delivery for Healthcare, FinTech, consumer platforms and Mobile App Development Iโ€™m an android developer focused on products where reliability and clean architecture matter. As a kotlin developer, I build scalable solutions with android kotlin best practices, Jetpack tooling and AOSP awareness. Clients come to me for android developer kotlin expertise when they need stability, lower technical debt and growth. I work as an android app developer on products that need more than interface implementation. I support teams with android app development for secure solutions where every android app stays maintainable after launch. My background: improving an android application used by thousands of users, integrating backend systems, payment flows, and healthcare-grade data handling. That is why companies hire me as an android mobile developer ( android mobile app developer ) when they need delivery. What I Do Best โœ… Android development using Kotlin and Java โœ… Architecture design with MVVM, Clean Architecture, modularization โœ… Backend communication, authentication and payment integrations โœ… Performance optimization, debugging, maintenance and release support โœ… Application Improvement for live mobile products โœ… Solo delivery or collaboration inside a larger team My strongest specialization is android developer kotlin work. I often join teams that need android developer kotlin java skills to modernize legacy code, migrate modules, and improve release quality without a full rewrite. That work benefits from practical experience as a java developer and from thinking like an android kotlin developer who can handle new features and stabilization. Relevant Experience Highlights ๐Ÿ”ธ Healthcare mobile applications with compliance-aware architecture ๐Ÿ”ธ Performance optimization and crash-rate reduction ๐Ÿ”ธ Secure data handling and app stability improvements ๐Ÿ”ธ Secure apps with payment integration and transaction-safe flows ๐Ÿ”ธ Backend integrations with PHP, Python, JavaScript, and REST APIs ๐Ÿ”ธ Collaboration with iOS, backend, QA, and web teams ๐Ÿ”ธ Ability to scale from one engineer to a delivery team I also have experience with android ble and android bluetooth features for pairing flows and reliable data exchange. Whether I contribute to an android mobile app or support an existing codebase as a mobile developer, I focus on release readiness. Tech Stack ๐Ÿ”ธ Android kotlin with Jetpack, Compose, Android SDK, AOSP ๐Ÿ”ธ Java, Firebase, secure cloud services, CI/CD ๐Ÿ”ธ REST APIs, secure auth, payment gateways ๐Ÿ”ธ Node.js, JavaScript, C#, SQL for backend alignment ๐Ÿ”ธ Git, Android Studio, release workflows, crash analysis ๐Ÿ”ธ MVVM, Clean Architecture, modular apps, scalability-first mindset My work is rooted in native Android, but I also understand broader product ecosystems. I collaborate effectively as an ios developer ( ios app developer ) when cross-platform alignment matters, including iOS Development discussions with teams using Swift. I have worked alongside teams using react native and reviewed delivery implications where flutter developer was involved, though I do not present those as my core specialization. That exposure helps me operate as an android developer and product-minded mobile app developer within cross-functional teams. Team & Product Collaboration ๐Ÿ”น Coordination with a rest api developer ๐Ÿ”น Alignment with web application development ๐Ÿ”น Communication with a web developer or front end developer ๐Ÿ”น Familiarity with database builder, django, and python automation Support I Can Provide โœ”๏ธ Build a mobile app from scratch โœ”๏ธ Join an existing product as an app developer android โœ”๏ธ Refactor legacy code and modernize architecture โœ”๏ธ fix android application bugs and improve release readiness I do not position myself as a wordpress, magento, game developer or unreal engine specialist and I do not use unrelated positioning such as android developer india. Even when someone types android develoer, they usually need a senior specialist who can take ownership. I built mobile applications for autism-related projects with intuitive user experience. ๐Ÿ“ฌ If you need an android developer who can improve an existing product, build a reliable solution from scratch or support growth with kotlin developer depth, send me a message.

  • Android
  • AOSP
  • Kotlin
  • Mobile App Development
  • Flutter
  • Node.js
  • Android App Development
  • Swift
  • Firebase
  • iOS Development
  • PHP
  • Java
  • JavaScript
  • React Native
  • C#
  • SQL
  • Software Design
  • Application Improvement
  • Software Development
  • Software Debugging
Dmitry T.

Barcelona, Spain

$70/hr
4.6
103 jobs

Hi, Iโ€™m Dmitry โ€” a full stack and mobile engineer who builds and ships production ready web and mobile applications. Top Rated freelancer with 80+ projects and 3000+ hours of development experience. I help startups and companies build scalable backend systems, modern frontend apps, and Flutter mobile apps (iOS and Android), including App Store and Google Play releases. What I do: - Full stack web apps (Laravel, PHP, React, Angular, JavaScript) - Flutter mobile apps from MVP to production release - Scalable backend systems and REST APIs - Integrations, payments, SaaS tools - Fixing, refactoring, and improving existing systems AI assisted development: - I use AI tools as a development accelerator to speed up delivery, improve iteration cycles, and increase code quality, always combined with manual engineering, architecture design, and production level review How I work: - I focus on shipping working production systems, not just code - I take ownership and build stable, scalable solutions Best fit for: - Startups building MVPs - SaaS products needing backend and frontend development - Teams needing a reliable full stack + mobile engineer

  • API Development
  • RESTful API
  • MySQL
  • HTML
  • CSS
  • Laravel
  • JavaScript
  • PHP
  • Angular
  • Bootstrap
  • React
  • PostgreSQL
  • AngularJS
  • Git
  • Web Application
Aleksandra L.

Alicante, Spain

$47/hr
4.9
169 jobs

I am Aleksandra, leading a team of experienced full-stack developers specializing in AI-driven applications. We design and develop modern, scalable web and mobile solutions that integrate artificial intelligence, automation, and cloud technologies to optimize business operations. With over 20+ years of collective experience, we have worked with startups and enterprises across industries like FinTech, Healthcare, eCommerce, and SaaS. Our expertise spans the entire development cycle, from initial concept and UI/UX design to backend architecture, AI integration, SRE (Site Reliability Engineering), and cloud deployment. ๐Ÿ† 194+ successful projects completed on Upwork with global clients ๐Ÿ’ฒ $5M+ earned on Upwork through high-impact full-stack and AI solutions โฑ 55,121+ hours billed, proving long-term client trust and engagement ๐Ÿ’ผ 600+ total projects delivered since 2000 across AI, web, and mobile ๐Ÿ“š 100% of developers hold engineering degrees, ensuring expert-level technical depth ๐Ÿ‘ฉโ€๐Ÿ’ป Advanced AI team includes Kaggle competition masters and top ML researchers ๐Ÿ“Š 91%+ job success rate, reflecting top-tier performance and consistency ๐Ÿš€ 25+ AI-driven apps deployed in FinTech, EdTech, and HealthTech ๐Ÿง  30+ machine learning models built and optimized for live environments ๐ŸŒŽ 20+ industries served, from startups to Fortune 500 clients ๐Ÿงฑ Founded in 2000, bringing 24+ years of experience in software innovation ๐Ÿ›  40+ React + Python full-stack solutions developed for scalable applications โšก High-load systems deployed to serve thousands of concurrent users ๐Ÿ“ˆ Client ROI increased by up to 70% in AI automation projects ๐Ÿ’ฌ Featured in Forbes, MBN Magazine, and Helsinki Times for client success stories Expertise: Full-stack development for web and mobile applications AI-powered solutions, including computer vision, natural language processing, and predictive analytics Scalable cloud architecture using AWS, Google Cloud, and Azure Real-time data processing and AI-driven automation Platform Engineering and Infrastructure as Code (IaC) GitOps workflows and CI/CD pipeline optimization API development and third-party service integrations Performance optimisation for high-traffic applications FinOps and cloud cost optimisation Secure and accessible web applications with SEO best practices Technology Stack: Frontend: React.js, Next.js, Vue.js, TypeScript Backend: Node.js, Python (FastAPI, Django, Flask), Golang AI & Machine Learning: TensorFlow, PyTorch, OpenAI API, Hugging Face, LLMOps Databases: PostgreSQL, MongoDB, Redis, Firebase Cloud & DevOps: AWS (Lambda, S3, DynamoDB, EC2), Docker, Kubernetes, Terraform, Helm, ArgoCD, GitHub Actions, GitLab CI/CD, Ansible, Prometheus, Grafana, ELK Stack Tools & Platforms: Figma for UI/UX, Miro for user flow mapping, Webflow for no-code development Why Work With Us? We focus on delivering intelligent, future-proof applications that drive business growth. Our team ensures seamless collaboration, clean code, and scalable architecture that adapts to evolving needs. We are committed to clear communication, efficient execution, and long-term support. If you are looking for a team that can build and scale AI-powered applications with a strong full-stack foundation, let's discuss your project. ๐Ÿ”‘ Keywords to find me: AI Developer | Full-Stack Developer | AI Applications | React Developer | Node.js Developer | Python Developer | AI Integration | SaaS Developer | Web App Developer | Mobile App Developer | Scalable Applications | AI-Powered Software | Computer Vision | NLP Engineer | Machine Learning Engineer | Backend Developer | Frontend Developer | Cloud Developer | Automation Engineer | Cloud Architect | GCP | AWS | Azure | TensorFlow | PyTorch | OpenAI | Hugging Face | FastAPI | Django Developer | Flask Developer | Golang Developer | MLOps | LLMOps | DevOps | SRE | Site Reliability Engineer | Platform Engineer | Kubernetes | Docker | Helm | ArgoCD | Terraform | Infrastructure as Code | IaC | GitOps | CI/CD | GitHub Actions | GitLab CI/CD | Jenkins | Ansible | Prometheus | Grafana | Datadog | ELK Stack | DevSecOps | FinOps | AIOps | Observability | Monitoring | Service Mesh | Istio | Crossplane | OpenTelemetry | HashiCorp Vault | Multi-Cloud | Serverless | Figma | Webflow | Miro | Firebase Developer | MongoDB Developer | PostgreSQL | Redis | REST API Developer | API Integration | Predictive Analytics | AI in FinTech | AI in Healthcare | AI in eCommerce | SaaS Application | Intelligent Automation | Real-Time Data Processing | Cross-Platform Developer | SEO-Friendly Development | Secure Web Applications | Scalable Web Architecture | UI/UX Focused Developer | AI SaaS Developer | AI-Powered Mobile Apps | Full-Cycle Development | AI Solutions for Business | Enterprise Software | Startup MVP Development | AI Team Lead | Cloud-Native Applications | Serverless Architecture | AI-Driven Optimization | AI Workflow Automation | Real-Time AI Solutions | AI-Enhanced UX | AI Web App | AI-Powered Dash

  • Python
  • Machine Learning
  • Generative AI
  • AI Agent Development
  • Machine Learning Model
  • Full-Stack Development
  • Node.js
  • React
  • Computer Vision
  • Mobile App Development
  • MLOps
  • DevOps
  • Docker
  • Kubernetes
  • Amazon Web Services
  • FastAPI
  • TensorFlow
  • Cloud Architecture
  • Natural Language Processing
  • Large Language Model
Pankaj S.

Barcelona, Spain

$15/hr
4.8
87 jobs

Hi, Iโ€™m Pankaj ๐Ÿ‘‹ A Shopify Expert with 10+ years of experience building high-converting E-commerce stores that drive traffic, sales, and long-term growth ๐Ÿ’ฐ I donโ€™t just build storesโ€”I create conversion-focused e-commerce systems designed to scale your business ๐Ÿ“ˆ ๐Ÿ’ผ What I Can Do for You ๐Ÿ›’ Shopify Store Design & Development Modern, clean & conversion-focused design Mobile-friendly & fast-loading stores โšก Custom Shopify development & features Scalable store structure โš™๏ธ Shopify Plus Development Advanced features & custom solutions High-performance UI/UX Built for scaling high-volume stores ๐Ÿ“ˆ E-commerce Optimization (CRO) Improve conversions & sales Better user experience & navigation Checkout optimization A/B testing-ready pages ๐Ÿ” Shopify SEO & Growth SEO-friendly product & category pages Keyword optimization for rankings Organic traffic growth strategies Technical SEO improvements ๐ŸŽฏ Landing Pages That Convert High-converting landing pages (PageFly, GemPages, Replo) Sales-focused layouts Built using proven buying psychology ๐Ÿ“ฆ Dropshipping & Store Setup Complete store setup Product research & winning products Supplier integration Optimized sales funnels ๐Ÿงฐ Tools & Platforms Shopify | Shopify Plus | WooCommerce | WordPress PageFly | GemPages | Replo | Klaviyo Google Analytics | SEO Tools ๐Ÿ“Š Results You Can Expect โœ” High-converting Shopify store โœ” Better user experience & trust โœ” Increased traffic & sales ๐Ÿ’ฐ โœ” SEO-ready structure โœ” Scalable e-commerce system ๐Ÿ’ฌ Why Work With Me? โœ” 10+ years real experience โœ” Conversion-focused approach (not just design) โœ” Clear communication & regular updates โœ” Focus on results, not just tasks ๐Ÿš€ Letโ€™s Build Something That Sells If you want a Shopify store that looks great AND converts, Iโ€™m here to help ๐Ÿ‘ ๐Ÿ“ฉ Send me a message and letโ€™s grow your e-commerce business! ๐Ÿš€

  • Ecommerce
  • Shopify
  • Shopify Templates
  • Shopify Website Design
  • Shopify Development
  • Ecommerce Website
  • Ecommerce Store Setup
  • Shopify Website Redesign
  • Shopify Plus
  • Shopify SEO
  • Ecommerce Site Setup
  • Landing Page Design
  • Web Design
  • Ecommerce SEO
  • Web Development
  • Ecommerce Website Development
  • Manage Ecommerce Site
  • Ecommerce Product Upload
  • Custom Ecommerce Store
  • Ecommerce Theme Installation

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