Backend Developer (Node.js / JavaScript)

Job Summary
Hubaix, a rapidly expanding AI SaaS and automation company based in Karachi, is looking for a full-time onsite Backend Developer with expertise in Node.js to join its core technical team. The company specializes in building enterprise-grade AI solutions, multi-agent automation platforms, and SaaS products that serve a diverse range of global industries including real estate, finance, logistics, healthcare, and hospitality. This role focuses on developing and maintaining scalable backend systems that power AI-driven SaaS platforms. The successful candidate will collaborate closely with frontend developers, AI engineers, product managers, and system architects in a fast-paced, innovative environment.

Key Responsibilities
Design and develop scalable RESTful and event-driven APIs using Node.js frameworks such as Express.js or Nest.js. Build and maintain modular backend architectures supporting multiple SaaS platforms. Develop seamless integrations with external APIs including CRMs, payment gateways, AI models, and automation tools. Create real-time backend systems leveraging WebSockets, event queues, and messaging brokers to ensure responsive user experiences. Optimize API performance, database queries, and response times for large-scale, multi-tenant SaaS environments. Collaborate with AI engineers to integrate backend services with AI agents, large language model (LLM) pipelines, and automation workflows. Design and implement secure authentication and authorization mechanisms using OAuth2, JWT, and role-based access control (RBAC). Maintain high backend code quality by ensuring modularity, testability, and comprehensive documentation. Work closely with full-stack teams to deliver fully integrated, end-to-end SaaS products.

Required Qualifications
A Bachelor’s degree in Computer Science, Software Engineering, or a related field is essential. Candidates must have at least 2 years of professional backend development experience using Node.js, particularly with Express.js or Nest.js frameworks. Strong expertise in RESTful API design, JSON data exchange, and API integrations is required. Proficiency with relational databases such as PostgreSQL or MySQL, as well as NoSQL databases like MongoDB and Redis, is necessary. A solid understanding of scalable backend architecture and multi-tenant SaaS systems is critical. Experience with asynchronous processing, event-driven workflows, and message queues (e.g., RabbitMQ or Redis Queue) is expected. Familiarity with Git for version control and hands-on experience deploying backend services in production environments using Docker, Linux, and cloud platforms is required. Strong problem-solving skills, attention to system stability, debugging capabilities, and the ability to write clean, modular, testable, and maintainable code are essential. Candidates must be available to work full-time onsite at the Karachi office.

Preferred Qualifications and Benefits
Preferred candidates will have experience integrating LLM AI models such as OpenAI, Claude, or OpenRouter, and familiarity with AI agent orchestration frameworks like LangChain, CrewAI, or Autogen. Knowledge of real-time streaming, WebSocket architectures, and live SaaS dashboards is a plus. Experience with SaaS billing systems, subscription management, and enterprise user management will be advantageous. Python backend development experience using FastAPI or Flask is considered a bonus. Exposure to serverless architectures such as AWS Lambda or Google Cloud Functions and familiarity with modern CI/CD deployment pipelines are also preferred.

Hubaix offers a competitive salary up to PKR 80,000 per month, commensurate with experience and skills. Additional benefits include performance-based bonuses, paid leaves including public holidays, and annual salary reviews with opportunities for growth and promotion. The role provides full onsite collaboration with daily team interaction and mentorship. Employees gain hands-on experience working on real-world AI-integrated SaaS platforms across various industries and the chance to learn from experienced AI SaaS product builders and technical architects.

This position is ideal for backend developers passionate about SaaS architectures, API engineering, and AI-powered platforms, seeking to contribute to cutting-edge enterprise solutions in a collaborative and growth-oriented environment.