Senior Full-Stack Developer - React, TypeScript, Node.js, Python & SaaS Dashboards

Position: Senior Full-Stack Developer Employment: Full-Time, Remote Experience: 6+ Years Availability: 30 hours/week, with more than 6 hours of daily overlap during US Central Time business hours Project: Existing SaaS Dashboard Development, API Integration & Modernization Project Overview We are looking for a highly experienced Senior Full-Stack Developer to take full ownership of an existing production SaaS platform and continue its development. The application includes complex dashboards, data management, reporting systems, interactive charts, geospatial mapping, background processing, and integrations with external APIs and services.[] The project involves enhancing the existing platform, integrating additional data sources, modernizing user interfaces, improving backend functionality, and ensuring reliable performance across the entire system. This is not a frontend-only or backend-only position. We need a developer who can independently handle the complete development lifecycle, from understanding the existing architecture and databases to implementing frontend and backend features, testing, and production deployment. Required Technical Skills Frontend Development - Strong React.js, TypeScript, JavaScript, HTML5, and CSS3. - Redux, React Context, and frontend state management. - Experience building complex, data-heavy SaaS dashboards. - Interactive charts, reporting modules, tables, filters, and visualizations. - Responsive UI development and performance optimization. Backend Development - Strong Node.js, TypeScript, Express.js, and RESTful API development. - Experience designing and maintaining complex backend services. - API authentication, authorization, validation, and error handling. - Asynchronous processing, background jobs, and task queues. - Experience with large datasets, database transactions, and performance optimization. - Ability to understand and maintain Python/Flask backend services when required. Database Development - Advanced MongoDB and Mongoose experience. - Strong understanding of database schemas, relationships, indexing, and aggregations. - Working experience with relational databases, especially MySQL or PostgreSQL. - Ability to trace and troubleshoot data flows across multiple systems. API Integration & Data Processing - Experience integrating multiple applications through REST APIs. - API security, authentication, data transformation, synchronization, and caching. - Experience handling complex JSON responses and external data sources. - Ability to design reliable integrations without disrupting existing business logic. GIS & Interactive Mapping - Experience with ArcGIS, Mapbox, MapLibre, Leaflet, or similar technologies. - Familiarity with GeoJSON, KML/KMZ, geographic coordinates, and spatial data. - Ability to build interactive maps with geographic boundaries, markers, polygons, and multiple data layers. Cloud Infrastructure & DevOps - Google Cloud Platform, particularly Cloud Run and Cloud Tasks. - Docker and containerized applications. - Git/GitHub, CI/CD pipelines, and deployment workflows. - Staging and production environment management. - Monitoring, debugging, and production troubleshooting. Key Responsibilities - Take end-to-end ownership of frontend, backend, database, API integration, and deployment tasks. - Quickly understand an existing production application originally developed by another engineer. - Review the current architecture, source code, Git history, documentation, and development workflows. - Understand previously completed work and continue development without unnecessary rewrites. - Develop new features across both frontend and backend. - Build and enhance complex dashboards, reports, and interactive visualizations. - Integrate external APIs and data sources into the existing application. - Implement advanced mapping and geospatial visualization features. - Modify and optimize database schemas, queries, aggregations, and data-processing workflows. - Handle backend services, authentication, authorization, background jobs, and data consistency. - Write maintainable, well-structured, and thoroughly tested code. - Independently troubleshoot and resolve frontend, backend, and infrastructure issues. - Manage staging and production deployments. - Provide accurate estimates, progress updates, and technical recommendations. - Deliver complete, working features independently, from implementation through testing and deployment. Critical Requirement: Existing Codebase Ownership We are looking for someone who can quickly become productive in an unfamiliar, actively maintained production codebase. You must be able to: - Understand another developer's existing architecture, coding patterns, and implementation decisions. - Trace complete workflows across frontend components, backend APIs, databases, and background processes. - Review previous commits and identify how existing features were implemented. - Continue ongoing development without disrupting existing functionality. - Identify architectural risks and technical dependencies before making changes. - Independently implement and deploy changes across the entire technology stack. - Work with minimal supervision and take responsibility for technical outcomes. We strongly prefer developers who have successfully taken over and extended complex production applications built by other engineers. Working Hours & Communication - Full-time commitment: 30 hours per week. - Must be available for more than 6 hours per working day during US Central Time (CDT/CST) business hours. - Must be available for regular meetings and technical discussions. - Strong English communication skills, both written and verbal. - Ability to work independently and solve technical problems proactively. - Regular progress reporting and clear communication about blockers. - Comfortable managing technical tasks and delivering features without continuous supervision. Preferred Qualifications - 6+ years of professional full-stack development experience. - Demonstrated experience with React, TypeScript, Node.js, Express, and MongoDB in production. - Python/Flask and MySQL experience. - Experience with large-scale SaaS applications and data-intensive dashboards. - Previous work with GIS, geospatial visualization, or mapping APIs. - Experience with Google Cloud deployment and background processing. - Strong understanding of application security, scalability, and performance. - Experience independently maintaining or modernizing legacy applications. Ideal Candidate We are looking for a senior-level developer who is equally comfortable working on frontend and backend systems. You should be able to understand complex existing software, make sound architectural decisions, implement complete features, and independently manage development through deployment. We value practical experience, problem-solving ability, clean code, reliable communication, and the ability to get up to speed quickly. How to Apply Please provide: 1. Your total years of professional full-stack development experience. 2. Examples of complex SaaS dashboards or production applications you have built or maintained. 3. Details of your React, TypeScript, Node.js, Express, MongoDB, and SQL experience. 4. Your experience with Python/Flask and integrating multiple backend systems. 5. Examples of GIS or interactive mapping features you have implemented. 6. An example of a project where you took over another developer's codebase and independently continued development. 7. Confirmation that you can work 30 hours per week with more than 6 hours of daily overlap during US Central Time business hours. 8. Your earliest availability to start and your expected hourly rate. Important: We are specifically seeking a developer capable of independently delivering complete full-stack features. Candidates who specialize exclusively in frontend or backend development are not suitable for this role Location & Communication Requirements Applicants must be based in one of the locations specified in this job posting and be available for more than six hours of daily overlap with US Central Time (CT). Excellent written and spoken English communication skills are required. We will only consider applicants who meet the stated location, availability, and communication requirements. Please confirm your location and working hours when applying.