Full Stack Developer interview questions & mock practice
What interview questions are asked for a Full Stack Developer?
A Full Stack Developer interview in 2026 runs across 4 rounds — frontend round, backend round, full-stack machine coding, system design & deployment. Below are the most-asked Full Stack Developer interview questions and a focused prep plan. Rehearse every answer out loud with the free timed practice below before the real one.
- JavaScript
- React
- Node.js
- SQL
- REST APIs
- Git
- Deployment
Free interview practice · Full Stack Developer
Practise your Full Stack Developer interview now — free
Step through the 12 most-asked Full Stack Developer questions one at a time, under a timer, just like the real thing. Jot your answer, then reveal what a strong answer covers. No signup needed to practise.
The Full Stack Developer interview process
End-to-end web engineering — frontend, backend, databases and deployment — for startups and product teams that want one engineer to own a feature.
1. Frontend round
JavaScript, React and UI fundamentals.
2. Backend round
API design, databases and server-side logic.
3. Full-stack machine coding
Build a small end-to-end feature (form → API → DB).
4. System design & deployment
Architecture, hosting, CI/CD and trade-offs.
Most-asked Full Stack Developer interview questions
12 of the questions Full Stack Developer candidates are asked most often in India. Practise answering each one out loud in the timed practice above.
- 1. Walk me through what happens from a user clicking a button to data being saved in the database.
- 2. How do you handle authentication and sessions in a full-stack app (JWT vs cookies)?
- 3. Explain CORS and how you fix a CORS error.
- 4. How do you structure a REST API for a CRUD application?
- 5. What is the difference between client-side and server-side rendering?
- 6. How do you prevent SQL injection and XSS in your app?
- 7. Explain state management on the frontend — when do you reach for a library?
- 8. How would you optimise a slow-loading web page end to end?
- 9. What is the difference between SQL and NoSQL, and when would you pick each for a project?
- 10. How do you handle environment variables and secrets across environments?
- 11. Describe your deployment pipeline from commit to production.
- 12. Tell me about a full-stack feature you built end to end.
How to prepare for your Full Stack Developer interview
Be genuinely comfortable on both sides — interviewers probe the half they suspect you're weaker on.
Practice one end-to-end machine-coding task: a form that hits an API and persists to a database, with validation.
Know the request lifecycle cold: browser → DNS → server → DB → response → render.
Understand auth thoroughly: JWT vs sessions, refresh tokens, password hashing and CORS.
Have a deployable side project on GitHub you can walk through, including CI/CD and hosting choices.
Practise other roles
- Software Engineer
- Frontend Developer
- Backend Developer
- Data Analyst
- Data Scientist
- Product Manager
- DevOps Engineer
- Java Developer
- Python Developer
- UI/UX Designer
- Sales / Business Development
- Digital Marketing
- HR / Recruiter
- Accountant
- Customer Support
- Data Engineer
- Machine Learning Engineer
- QA / Test Engineer
- Android Developer
- iOS Developer
- Business Analyst
- Project Manager
- Scrum Master
- SQL Developer
- React Developer
- Node.js Developer
- Cloud Engineer (AWS)
- Cybersecurity Analyst
- Network Engineer
- Database Administrator
- SEO Specialist
- Content Writer
- Graphic Designer
- Sales Executive
- Business Development Manager
- Operations Manager
- Financial Analyst
- Chartered Accountant
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- Technical Support Engineer
- Civil Engineer
- PHP Developer
- .NET Developer
- Golang Developer
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- Salesforce Developer
- Site Reliability Engineer (SRE)
- Embedded Systems Engineer
- WordPress Developer
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- Power BI Developer
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- Relationship Manager (Banking)
- Branch Manager
- Area Sales Manager
- Investment Banking Analyst
- Tax Consultant
- Supply Chain Manager
- Executive Assistant
- Data Entry Operator
- Telecaller / Telesales Executive
- Retail Store Manager
- Vue.js Developer
- Ruby on Rails Developer
- Kotlin Developer
- iOS Swift Developer
- React Native Developer
- Azure Cloud Engineer
- GCP Cloud Engineer
- DevSecOps Engineer
- Platform Engineer
- MLOps Engineer
- Data Warehouse Engineer
- Solution Architect
- Automation Test Engineer (Selenium)
- Manual Test Engineer
- Performance Test Engineer
- IT Support Engineer
- System Administrator
- Cloud Security Engineer
- Penetration Tester (Ethical Hacker)
- SOC Analyst
- Business Intelligence Analyst
- QA Lead
- Informatica Developer
- Mainframe Developer
- Production Engineer
- Quality Engineer (QA/QC)
- Design Engineer (Mechanical)
- Maintenance Engineer
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- Piping Engineer
- HVAC Engineer
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- Site Engineer (Civil)
- Safety Officer (HSE)
- CNC Programmer
- Quantity Surveyor
- Staff Nurse
- Pharmacist
- Medical Representative
- Lab Technician
- Physiotherapist
- Radiology Technician
- Dietitian / Nutritionist
- Clinical Research Associate
- Hospital Administrator
- Medical Coder
- Biomedical Engineer
- Microbiologist
- Business Development Executive
- Key Account Manager
- Marketing Manager
- Brand Manager
- Product Marketing Manager
- Content Marketing Manager
- Social Media Manager
- Performance Marketing Specialist
- Financial Advisor
- Credit Analyst
- Auditor (Statutory/Internal)
- Company Secretary (CS)
- School Teacher
- College Professor / Lecturer
- Primary School Teacher
- Customer Service Representative
- Back Office Executive
- Operations Executive
- Logistics Coordinator
- Procurement Executive
- HR Manager
- Recruiter / Talent Acquisition
- Training Manager
- UI Designer
Full Stack Developer interview — FAQs
What questions are asked in a Full Stack Developer interview?
Common Full Stack Developer interview questions include: Walk me through what happens from a user clicking a button to data being saved in the database. How do you handle authentication and sessions in a full-stack app (JWT vs cookies)? Explain CORS and how you fix a CORS error. How do you structure a REST API for a CRUD application? Interviews usually run across 4 rounds — Frontend round, Backend round, Full-stack machine coding, System design & deployment. Practise them with the free timed practice on this page.
How many rounds are in a Full Stack Developer interview?
A typical Full Stack Developer interview has 4 rounds: Frontend round (JavaScript, React and UI fundamentals.); Backend round (API design, databases and server-side logic.); Full-stack machine coding (Build a small end-to-end feature (form → API → DB).); System design & deployment (Architecture, hosting, CI/CD and trade-offs.).
How do I prepare for a Full Stack Developer interview?
To prepare for a Full Stack Developer interview: Be genuinely comfortable on both sides — interviewers probe the half they suspect you're weaker on. Practice one end-to-end machine-coding task: a form that hits an API and persists to a database, with validation. Know the request lifecycle cold: browser → DNS → server → DB → response → render. Then rehearse every question out loud with the timed practice on this page before the real thing.
What skills do I need for a Full Stack Developer role?
Core Full Stack Developer skills tested in interviews include JavaScript, React, Node.js, SQL, REST APIs, Git, Deployment. OnJob shows you exactly which of these skills stand between you and a 100% match on every live Full Stack Developer job.
Is the Full Stack Developer mock interview practice free?
Yes. The questions, the answer guidance and the timed practice on this page are free and need no signup. With a free OnJob account you can also take timed role tests and free certification tests. Personalised AI role and skill tests are part of the paid plans.
Ace your Full Stack Developer interview
Rehearse every Full Stack Developer question out loud on this page, then sign in to take a timed role test or a free certification in the OnJob practice hub.
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