Hire the best JavaScript Developers in Saint Charles, MO

Check out JavaScript Developers in Saint Charles, MO 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 140 client reviews
  • $30 hourly
    Hello! I'm a full-stack developer who thrives on creating engaging web applications. With expertise in JavaScript, Python, React.js, and hands-on experience in developing API endpoints using Node.js and Python, I have the skills to bring your vision to life. Whether it's crafting a captivating online portfolio, creating a unique e-commerce site, or designing an innovative web application, there's no limit to what we can achieve together. I'm ready to bring your vision to life, let's create something amazing! • Skilled in JavaScript, Python, HTML5/CSS3, ReactJS, NodeJS, MongoDB, and SQL.
    vsuc_fltilesrefresh_TrophyIcon JavaScript
    User Authentication
    Front-End Development
    Technical Documentation Management
    API Development
    MongoDB
    SQL
    HTML5
    Node.js
    React
    Python
    CSS
    Bootstrap
    Adobe Photoshop
  • $40 hourly
    vsuc_fltilesrefresh_TrophyIcon JavaScript
    React
    Node.js
    ExpressJS
    Python
    Responsive Design
  • $65 hourly
    Senior .NET Engineer with 20 years of experience in designing, developing, and maintaining enterprise-level software solutions. Proficient in leveraging .NET technologies to build scalable, high-performance applications with a strong focus on backend services, APIs, and database management. Adept at collaborating with cross-functional teams, optimizing legacy systems, and implementing modern architectural patterns. Passionate about delivering reliable, maintainable code that drives business success. SKILLS Languages - C# - JavaScript/ECMAScript - TypeScript - SQL - Python - Shell (bash, ksh, sh) - Java Frameworks and Platforms - .NET Core - ASP.NET Web API - Entity Framework - ASP.NET MVC - Blazor - WPF - Razor Pages Databases - Microsoft SQL Server - PostgreSQL - MongoDB - Oracle - DynamoDB - Cosmos DB Tools and DevOps - Visual Studio - Azure DevOps - Git - Jenkins - Docker - Terraform - Kubernetes - Octopus Deploy Other Skills - Microservices Architecture - RESTful APIs - ETL Development - Scalable Systems Design - Test-Driven Development (TDD) EXPERIENCE Chief Architect - Alpha Virtual, Orlando, FL (Remote) February 2019 - January 2025 - Architected and implemented backend systems for **VirtualTrade Platform**, leveraging .NET Core and Entity Framework to handle millions of cryptocurrency transactions daily. - Designed scalable APIs for the **AlphaStaking Hub**, ensuring seamless integration with blockchain networks using ASP.NET Web API. - Built a fault-tolerant distributed ledger solution using Azure Functions and Cosmos DB, improving data consistency and availability. - Developed the **QuantAI Analytics** platform for real-time cryptocurrency market predictions using C#, Python, and Azure Synapse Analytics. - Implemented advanced authentication and authorization flows using Azure Active Directory (AAD) and JWT. - Enhanced performance by optimizing SQL Server queries and utilizing caching mechanisms, reducing response times by 40%. - Built CI/CD pipelines with Azure DevOps to automate deployments and testing, increasing release frequency by 50%. - Designed and monitored real-time alerts and metrics using Azure Monitor and Application Insights, ensuring 99.9% system uptime. - Migrated monolithic services to microservices architecture, improving scalability and maintainability. - Mentored a team of 15 engineers in .NET best practices, fostering professional growth and improving team productivity. Lead Developer/Solutions Architect - Sequoya Holdings, Sarasota, FL (Remote) Feb 2017 - Feb 2019 - Led the development of Everyday Price Analytics, implementing .NET Core and SQL Server for predictive pricing models and elasticity analysis. - Built scalable ETL pipelines to process high volumes of trade data using SSIS and .NET Core. - Architected RESTful APIs for Trade Promotion Optimization, integrating with external retail systems and enhancing reporting accuracy. - Designed the Sales Planner Tool with Razor Pages and ASP.NET MVC, enabling financial forecasting and scenario simulations for trade teams. - Developed advanced reporting capabilities with SQL Server Reporting Services (SSRS), improving insights for pricing managers. - Created dynamic dashboards using Blazor to visualize real-time sales data, reducing decision-making time by 30%. - Refactored legacy systems into a microservices architecture using Docker and Kubernetes, improving performance and scalability. - Integrated robust logging and monitoring solutions using Serilog and Azure Log Analytics. - Developed automated unit and integration tests with xUnit and NUnit, achieving 85% code coverage. - Collaborated with business stakeholders to align technical solutions with strategic goals, improving client satisfaction. Tech Lead/Solutions Architect - Frontline Technologies, Malvern, PA (Remote) February 2010 - February 2017 - Spearheaded the migration of legacy systems to .NET Core for the **OASYS Teacher Evaluation System**, enhancing scalability and reducing operational costs. - Designed and implemented ETL pipelines using SQL Server Integration Services (SSIS) for large-scale data processing and reporting. - Built secure APIs for the **Frontline Insights Platform** using ASP.NET Web API, integrating with multiple third-party systems. - Developed a Professional Learning Platform leveraging Entity Framework and Razor Pages, streamlining workflows for over 1 million users. - Refactored monolithic applications into microservices using Docker and Kubernetes, improving deployment flexibility and fault tolerance. - Conducted performance tuning on SQL Server databases, reducing query execution times by 3%. - Created CI/CD pipelines with Jenkins to automate testing and deployments, enhancing developer productivity. - Collaborated with cross-functional teams to design user-centric solutions, aligning technical implementations with business objectives.
    vsuc_fltilesrefresh_TrophyIcon JavaScript
    AWS Lambda
    ASP.NET MVC
    C#
    SQL
    Ext JS
    .NET Framework
    React
    jQuery
  • $26 hourly
    Meet Cristian Ferreira, a driven software development student with experience in Python, JavaScript, and SQL. I am passionate about the intersection of technology and innovation, constantly seeking new ways to improve upon existing systems and processes. In addition to my technical skills, they also bring valuable experience in customer service and sales support. I have worked in a professional environment as a sales support representative, where they honed my communication and problem-solving skills. This experience has taught me the importance of delivering top-notch customer service and working collaboratively with teams to achieve common goals. Currently, I am focused on expanding their knowledge and expertise in software development, particularly in the areas of web development and data analysis. They are constantly exploring new technologies and tools to enhance their skill set and stay current in the fast-paced world of software development. With a keen eye for detail and a passion for coding, I am dedicated to creating efficient and effective software solutions that meet the needs of businesses and individuals alike. Whether working independently or as part of a team, I am committed to delivering high-quality results and exceeding expectations. If you're looking for a talented software development student with a diverse skill set and a passion for innovation, I think I am the perfect candidate for your next project.
    vsuc_fltilesrefresh_TrophyIcon JavaScript
    Software Development
    Python
    CSS
    Data Analysis
    SQL
    HTML
    Microsoft Excel
    Customer Service
    Marketing
    Sales & Marketing
  • $33 hourly
    My name is Terry. I am highly skilled but with few credentials. I want to be a freelancer in order to do what I'm passionate about, Most of the skills that I've listed have been lifelong hobbies that have turned into opportunities. I'm a project kind of guy. I have infinite energy to accomplish a goal relating to these skills. I have a Highschool Diploma and I have some college here and there, relating to my interests rather than a degree. I am currently developing platform independent tools for an interactive touchscreen environment as a new standard model.
    vsuc_fltilesrefresh_TrophyIcon JavaScript
    Microsoft Visual Studio
    Music Production
    Audio Mastering
    Music & Sound Design
    Sound Mixing
    CAD & CAM Software
    CSS 3
    HTML5
    XML
    Video Editing
    Graphic Design
    Python
    SQL
    Typing
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