Hire the best JavaScript Developers in Simi Valley, CA

Check out JavaScript Developers in Simi Valley, CA with the skills you need for your next job.
Clients rate JavaScript developers
Rating is 4.8 out of 5.
4.8/5
based on 2,042 client reviews
  • $50 hourly
    I’m James Dab-go-tra, Los Angeles native. I've been designing and building websites for two decades. I’m a full-stack LAMP/LEMP web developer with expertise in fully developing and managing enterprise-level sites. I work with JavaScript, PHP, mySQL, and Nginx. I have a knack for realizing the visions of designers. I’ve been developing and fully managing custom WordPress themes and plugins since 2009. I have an expert knowledge in plugins, including avoiding plugins that add bloat. I emphasize performance, SEO, and clean and maintainable code.
    Featured Skill JavaScript
    PSD to WordPress
    Back-End Development
    Front-End Development
    MySQL Programming
    WordPress Theme
    Linux System Administration
    WordPress Development
    PSD to HTML
    CSS
    HTML
    PHP
    WordPress
    NGINX
  • $53 hourly
    I’m a U.S.-based full-stack developer with hands-on experience building production-ready web, mobile, and backend systems. I work with React, Next.js, TypeScript, Python, and FastAPI to deliver reliable, scalable software for startups and growing businesses. 🖥️ Frontend Development I build responsive, modern interfaces using React and Next.js with TypeScript. I also develop cross-platform mobile apps with React Native, using MobX or Redux for complex state handling. ⚙️ Backend and API Work I create fast, maintainable APIs using FastAPI and Python. I work with PostgreSQL for relational data, Redis for caching and async flows, and Docker for clean deployments. I’ve built systems with background job processing, webhook handling, and multi-environment support. 🧠 ML Pipelines and Automation I’ve designed and shipped machine learning pipelines for sentiment analysis and content scoring using tools like Pandas, Scikit-learn, and Hugging Face. I also build automations that reduce manual work, streamline reporting, and save clients hours per week. 🔌 Integrations and External APIs I integrate with a wide range of third-party services including Stripe, Google APIs, social media platforms, CRM tools, and internal systems. I’ve built custom logic around authentication, webhooks, data syncing, and usage tracking to connect client systems with the tools they already rely on. ✅ What You Get Clean, maintainable code. Fast turnaround. Clear communication. I focus on solving real business problems, not just shipping code. Available for new development, maintenance, and automation projects. Let’s work.
    Featured Skill JavaScript
    Next.js
    Web Design
    Web Development
    HTML
    C++
    CSS
    Python
  • $68 hourly
    🙋🏻‍♂️ I'm an Upwork "Top Rated Plus" and "Skill Certified" software engineer from Simi Valley, CA. Over the past 7 years I have worked for countless enterprise clients. 💯 WHY CHOOSE ME OVER OTHER FREELANCERS? ✅ Top 1% of all software developers on the platform - certified by Upwork. ✅ I only work with ONE client at a time. You will never have to compete for my attention ✅ I can take your application the full life-cycle from architecture, development, testing to hosting on AWS. ✅ Senior level skills in React, Node.js with Javascript and Typescript. ✅ Senior Level skills in multipe frameworks like Redux, Socket.io plus all available database technologies via Sequelize and/or Mongoose. ✅ I provide daily written updates on the progress of the application ❌ No short projects! 3 months plus only! ❌ No company shares will be accepted, I only work for payment and I only work for well funded clients. ❌ I can't provide UI designs. I am purely a programmer. ❌ I understand the importance of keeping the owners informed. However, daily stand-ups can sometimes disrupt the workflow and reduce the available time for development. While I am willing to participate in stand-ups, it's important to consider that frequent meetings may impact the overall project timeline. 🚀 Let's get started!
    Featured Skill JavaScript
    NGINX
    Business with 100-999 Employees
    API
    HTML5
    CSS
    HTML
    Node.js
    Web Application
    MongoDB
    Sequelize
    Flexbox
    Software Development
    React
  • $60 hourly
    I have been a professional web developer for 19 years, including 16 years as a freelancer. Most projects I've brought from the design phase to full implementation and launch, with budgets in the tens of thousands of dollars. These have included integration into Joomla for community/social networking based sites using Joomla and WordPress, and Magento for e-commerce, with an emphasis on customization/implementation of project specific functionality. After implementation, I continue on through the long-term maintenance phase, and implement new features as requirements shift. I enjoy trying out new techniques, and coming up with innovative solutions to challenges. My skills include full stack development, from moderate server administration to back end/front end development, external API integration, AJAX functionality, responsive site implementation, and advanced Javascript UI.
    Featured Skill JavaScript
    Magento
    Ecommerce Website Development
    PHP
    Joomla
    CSS
    MySQL
    Laravel
    API Integration
    AJAX
  • $15 hourly
    Hello, I am a skilled and experienced freelancer with expertise in HTML5, CSS, JavaScript, Angular, and React. I specialize in creating custom websites and webpages tailored to your specific needs, ensuring a professional and polished end result. With my knowledge and expertise, I can design and develop your online presence just the way you envision it. Let's work together to bring your ideas to life and create a stunning and functional website for your business or personal brand.
    Featured Skill JavaScript
    App Development
    Node.js
    ExpressJS
    GitHub
    jQuery
    Bootstrap
    Angular
    React
    Web Development
    CSS 3
    HTML5
    SQL
    C++
  • $50 hourly
    With over a decade immersed in the world of web and desktop app development, I've become a seasoned pro in navigating the intricacies of software creation and the full Software Development Life Cycle (SDLC). I bring a wealth of experience to the table, capable of managing every aspect of crafting top-tier systems while ensuring client needs are not just met, but exceeded. My portfolio boasts a diverse array of projects spanning industries such as Education, Government, Finance, and Employment Services. This breadth of experience equips me with the versatility to take on any challenge with confidence. One of my standout skills is my ability to demystify technical complexities, translating them into plain language that everyone can understand. Whether it's a one-on-one conversation or a group setting, I make sure everyone is on the same page, fostering clear communication and collaboration. Here's a snapshot of my expertise: 🚀 Proficient in .Net 8, .Net Framework, WPF, UWP, and ASP.NET for robust backend development. 🚀 Well-versed in SQL Server, MySQL and Oracle for efficient database management. 🚀 Specialized in building scalable systems that can grow alongside your business without missing a beat. 🚀 Skilled in Typescript, JavaScript, jQuery, HTML, CSS, Bootstrap for creating dynamic and user-friendly frontend interfaces. 🚀 Capable of crafting APIs using Rest API, and Firebase to facilitate seamless integration. 🚀 Familiar with cloud platforms like Azure and AWS for scalable and reliable hosting solutions. I'm eager to bring my expertise to your team, collaborating to deliver exceptional results and drive your projects to success.
    Featured Skill JavaScript
    Web API
    LINQ
    Model-View-Controller
    .NET Core
    Microsoft IIS
    GitHub
    AJAX
    jQuery
    Bootstrap
    CSS 3
    HTML5
    Microsoft SQL Server
    C#
    Entity Framework
  • $75 hourly
    Want to build a great online community to achieve great things? NationBuilder is an accessible, affordable software platform that helps leaders grow and organize communities to achieve great things Let Outreach Nation help transform your vision into an engaging Social Media driven machine guaranteed to get you votes, customers, donations, volunteers, or whatever it is that you desire We take full advantage of NationBuilder’s easy-to-update websites which include a people database and communication tools like email, text messaging and social media – all in one system. Businesses, nonprofits, governments, and politicians use NationBuilder to organize their communities and build more meaningful relationships with customers, supporters, and constituents. OUTREACH: NATION is a full service web design and online marketing firm established in 2010. We specialize in building elegant highly functional websites in both the Wordpress & NationBuilder platforms. We have been Certified NationBuilder Architects & Experts for approximately 1 year now and have worked with clients ranging from Political Parties, Advocacy Groups, Non Profits, Musicians, Restaurants, & Businesses.
    Featured Skill JavaScript
    Ruby on Rails
    CSS
  • $22 hourly
    Experienced IT professional with over 25 years in Quality Assurance and software development, specializing in test management, automation, and large enterprise applications. Proven track record in: • Leadership and Management: Spearheaded distributed QA teams (onsite and offshore) and streamlined processes for enhanced efficiency. • Automation and Frameworks: Developed and implemented customized automation frameworks, guided script development, and conducted ROI analyses. • QA Methodologies: Crafted and executed comprehensive test plans for UI, APIs, Data Warehousing, and ETL processes. • Client and Vendor Relations: Managed client relationships and facilitated vendor demos, ensuring alignment with business needs. • Stakeholder Engagement: Collaborated with UAT testers, business users, and vendors to drive successful project outcomes. • Technical Proficiency: Leveraged strong technical skills to address complex issues and deliver effective solutions. • Communication and Leadership: Provided mentorship and training, exhibiting excellent analytical and people skills. • Continuous Improvement: Applied an entrepreneurial approach to enhance processes and explore emerging technologies. • Domain Expertise: Recognized Subject Matter Expert (SME) in Mortgage/Fintech, Payment systems, also good understanding Healthcare and Digital Marketing, IoT’s.
    Featured Skill JavaScript
    Full-Stack Development
    React
    Test Management
    TypeScript
    API Testing
    SQL
    Cypress
    Postman
    Automated Testing
    Quality Assurance
    Test Results & Analysis
    Software Testing
    QA Testing
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