Senior Node.js Full Stack Developer - TJ / 1865380

Our client Younes Biane is looking for a Senior Node.js Full Stack Developer in Karachi

Senior Full Stack Node.js Developer (Remote, Freelance)

We are a small development team from Germany building a series of AI powered SaaS products for international markets. In this senior role, you will build reliable and scalable backend solutions with Node.js, Express and PostgreSQL. You will design and evolve database schemas and migrations, implement background jobs and workers, integrate external APIs and webhooks, and ship features that are ready for production. You work directly in our GitHub repository as a collaborator. Your development process is test first, ensuring high quality code before anything is merged via pull requests. You will document your work clearly and participate in code reviews. You will not manage a team, but your expertise will shape the technical direction of the product. You will also work with vector databases (pgvector) for our knowledge layer and with deployment on DigitalOcean through CI/CD pipelines.

How we work: AI first with agentic coding. Claude Code is our main tool and a Claude Max plan is provided by us; we also use ChatGPT and Kimi in our workflow. The model is the same for everyone, what differs is the person in front of it. You steer the AI agent, you verify its output, and you own the result.

Requirements: at least 4 years of production experience with Node.js, Express and PostgreSQL. Solid Git and pull request workflow. Test driven development is a hard requirement. Good written and spoken English, as all collaboration runs in English. Experience with Redis, queues, webhooks, Stripe or Paddle billing, and vector databases is a plus.

Compensation: 450 PKR per hour, fixed, billed on actual hours worked via monthly invoice. Payment in PKR through Wise or Payoneer. The regular scope is 8 hours per day, 6 days per week, which comes to about PKR 93,600 per month. Additional hours are possible from the start and are paid at the same rate, bringing the monthly figure to around PKR 100,000. Once our first product is live and generating revenue, percentage based bonuses are planned on top.

Process: shortlisted candidates receive a practical test task to be solved with AI, plus a questionnaire. The selected candidate receives a small verification payment of about 5 USD before the contract starts. No candidate ever pays anything at any stage of this process. Immediate start possible, with a trial month based on weekly goals agreed in advance.

Responsibilities

• Develop and enhance backend features using Node.js and Express.js for AI-powered text, photo, and video processing SaaS products.
• Design, implement, and maintain PostgreSQL data models and perform database migrations to support evolving product needs.
• Create, test, and maintain RESTful APIs to enable integration with frontend applications and third-party services.
• Implement background jobs and worker processes to manage asynchronous tasks and improve system performance.
• Integrate AI provider APIs and develop webhook-based payment flows to facilitate seamless user experiences and monetization.
• Build and polish progressive web application (PWA) frontends using Vanilla JavaScript and Alpine.js to ensure responsive and engaging interfaces.
• Follow test-driven development practices rigorously by writing tests before code implementation and ensure all tests pass before merging.
• Submit well-documented code changes through GitHub pull requests and participate actively in code review processes.
• Conduct development and testing activities on the staging server to ensure stability and reliability before live deployment.
• Collaborate with the founder for live deployment and continuous integration and delivery processes using CI/CD pipelines.
• Use Redis to manage caching and improve application performance when required.
• Leverage version control tools such as GitHub and GitHub Pull Requests to maintain code integrity and team collaboration.
• Utilize containerized or cloud deployment platforms like DigitalOcean to host applications and services securely and efficiently.
• Employ vector databases and libraries such as pgvector to manage complex data structures that support AI features.
• Maintain clear and concise technical documentation and ensure communication is effective in English for knowledge sharing and future reference.