Full-Stack Developer (React/Node/PostgreSQL) – Long-Term SaaS Development

Full-Stack Developer (React/Node/PostgreSQL) – Long-Term SaaS Development

Full-Stack Developer (React/Node/PostgreSQL) – Long-Term SaaS Development

Upwork

Upwork

Remoto

13 hours ago

No application

About

We’re building a suite of B2B SaaS tools for Amazon sellers and agencies. This is a long-term position, not a one-off project. You will be our primary developer as we build and maintain multiple dashboards and web applications over the coming years. You need to be comfortable owning a codebase, making technical decisions, and shipping real product – not just small CRUD apps. The core stack we expect you to use: – Backend: Node.js (TypeScript preferred) with REST APIs (Express/Fastify). Python (FastAPI) for ETL/background jobs is a strong plus – Frontend: React (Next.js or SPA), component-based UI, responsive design, light/dark mode basics – Data: PostgreSQL (preferred) or PostgreSQL + some MongoDB, schema design for multi-tenant SaaS, aggregations, indexing – Infrastructure: basic AWS / cloud deployment, Docker, Git/GitHub, simple CI/CD What you’ll actually be doing (first project – Account Health Dashboard): – Implement backend services that ingest JSON/CSV reports from Cajari (Amazon Seller Central data extraction), normalize them, and store them in a multi-tenant database – Design and implement database schemas for clients, seller accounts, policy violations, metrics snapshots, and workflow/work history – Build a secure backend with role-based access (Admin, Staff, Client) and strict tenant isolation on every query – Expose clean REST APIs for the frontend (metrics, trends, filters, pagination) – Turn detailed dashboard designs (tables, filters, charts, badges) into reusable React components – Implement account-health KPIs, trends, and alert logic on the backend and surface them cleanly in the UI – Handle pagination, filtering, and sorting for large datasets (10k+ rows per account) – Pay attention to reliability, data validation, and simple but solid error handling throughout the stack What you’ll do next (this is ongoing work, not just one dashboard): – Build additional monitoring dashboards for different Amazon / e-commerce data sources – Develop client-facing reporting tools and self-service portals – Create internal operations and case-management applications for our team – Implement automation and workflow tools (alerts, queues, background jobs, scheduled reports) – Help shape architecture decisions as the product suite grows over time Requirements: – 3–5+ years of full-stack experience with Node.js and React (Python experience is a strong plus) – Very comfortable designing relational schemas and writing clean, efficient SQL queries (PostgreSQL strongly preferred) – Proven experience building at least one serious dashboard or B2B SaaS product end-to-end (not just tutorials) – Strong understanding of authentication, authorization, and multi-tenant patterns (tenant_id, RBAC, etc.) – Ability to read existing HTML/CSS or Figma and refactor it into reusable components instead of starting from scratch every time – Solid Git/GitHub habits, code reviews, and basic testing (unit/integration) – Good written English and willingness to communicate clearly in async updates and short Loom walkthroughs when needed Nice-to-have: – Prior experience with Amazon Seller Central or other e-commerce dashboards – Familiarity with queues/background workers and ETL/data pipelines (BullMQ, Celery, cron-based workers, etc.) – Experience with charting libraries (Recharts, Chart.js, etc.) – Experience deploying and operating apps on AWS or similar cloud providers This is NOT a one-off project. We are looking for a long-term partner who can stay with us, own the codebase, and continue building additional dashboards, internal tools, and web applications after the first version ships. When you apply, please: – Answer the screening questions carefully – Include links to 1–2 dashboards or SaaS apps you actually built (GitHub and/or live demos) – Briefly confirm your weekly availability and your timezone