Work centers on implementing well-defined features and fixing bugs under supervision. Juniors write RESTful API endpoints, connect to databases with ORMs (Sequelize, Mongoose), and maintain code quality with unit tests (Jest, Mocha). They also assist in debugging, documenting endpoints, and learning about asynchronous programming in Node.js (Promises, async/await). Familiarity with Git, Postman, and CI/CD basics is developed, with the focus on building clean, testable code and understanding back-end fundamentals.

Semi-senior developers independently manage back-end modules, ensuring scalability and security. They design API structures, integrate third-party services (payment gateways, authentication providers), and optimize database queries. Responsibilities include configuring Docker containers for local development, writing integration tests, and contributing to CI/CD pipelines. At this stage, performance profiling tools and cloud deployment (AWS Lambda, Azure Functions, or Kubernetes) become standard, along with mentoring juniors in best practices.

Senior developers lead technical direction within Node.js projects. They design microservices architectures, implement advanced caching (Redis, Memcached), and manage event-driven systems with queues like RabbitMQ or Kafka. Senior responsibilities include enforcing security standards (OWASP, JWT handling, OAuth2 flows), scaling applications for high traffic, and conducting in-depth code reviews. They mentor team members, set coding standards, and evaluate frameworks (NestJS, Express, Fastify) to guide project decisions. Strong collaboration with DevOps and front-end leads is critical at this level.

The managerial role balances strategic planning with technical oversight. Node.js Development Managers oversee multiple back-end teams, define architecture roadmaps, and align development priorities with business goals. They coordinate with product managers on feature delivery, manage vendor and cloud service contracts, and set performance KPIs for applications. A key part of the role is driving adoption of emerging technologies, ensuring cost-efficient infrastructure, and cultivating engineering excellence through training and process improvements. By combining leadership with deep technical insight, managers ensure Node.js platforms remain secure, scalable, and business-aligned.