Senior Full-Stack Developer

Jellyfish Technologies · Uttar pradesh, India

Role Purpose Own end-to-end feature development across the stack, with complete responsibility for implementation, automated testing, code quality, and production reliability.

Key Responsibilities

Develop and deliver end-to-end features using React and Firebase Functions.

Write, maintain, and improve unit and integration tests using Jest and React Testing Library.

Participate actively in code reviews and follow the standard of two reviewers per pull request.

Debug and resolve production incidents, identifying root causes and implementing reliable fixes.

Collaborate closely with the Product Manager to define clear and testable acceptance criteria. Contribute to engineering best practices, maintainability, and overall product quality.

Technical Requirements

5+ years of experience in web development.

3+ years of hands-on experience with React and Node.js.

Strong TypeScript development experience.

Hands-on experience with Firebase and Firestore.

Experience working with Google Cloud Platform (GCP).

Familiarity with Firebase Emulators for local development and testing.

Demonstrable experience writing and maintaining automated tests.

Strong understanding of unit and integration testing practices. Quality & Engineering Mindset

Treat testing as an integral part of development rather than a separate QA activity.

Follow a test-first or TDD-oriented approach where appropriate.

Prioritize meaningful, high-value tests that protect critical business functionality.

Understand the value of code coverage while avoiding arbitrary coverage targets without business or technical value. Interview Signals / What We Look For

Clearly explains their approach to testing and demonstrates a test-first mindset or practical TDD experience.

Can share real examples of defects identified through automated tests before production deployment. Understands the difference between meaningful test coverage and simply increasing a coverage percentage.

Demonstrates strong ownership of feature quality, debugging, and production reliability.

Ideal Candidate A hands-on full-stack engineer who takes ownership from requirements and acceptance criteria through development, testing, code review, deployment, and production support. The ideal candidate combines strong React/Node.js skills with a strong quality mindset and practical experience building reliable applications on Firebase and GCP.