What Is the Machine Coding Round in Frontend Interviews?

What Is the Machine Coding Round in Frontend Interviews?

The machine coding round is a 90-minute round where you build a UI component or small app from scratch. It is one of the most common rounds in frontend interviews at top companies.

What You Get

• A problem statement describing a UI component or app to build.
• 90 minutes to complete it.
• Access to a code editor (sometimes with internet, sometimes without).
• You build in HTML, CSS, and JavaScript (vanilla or React, depending on the company).

What They Evaluate

1. Functionality: does the component work as specified?
2. Code quality: is it clean, modular, readable?
3. Edge cases: did you handle empty states, errors, and boundary conditions?
4. UI/UX: does it look good and feel right?
5. Approach: how did you structure the code and solve the problem?

Common Questions

• OTP input component with auto-focus.
• Progress bar with animations.
• Autocomplete search bar with debounce.
• Pagination component.
• Multi-step tab form.
• File explorer (tree view).
• Food ordering app with cart and filters.
• Image carousel.
• Accordion.
• Modal/dialog.

How to Crack It

1. Read the problem twice (5 minutes).
2. Clarify requirements with the interviewer.
3. Plan the structure (HTML, state, events) (5-10 minutes).
4. Build core functionality first (40-50 minutes).
5. Handle edge cases (10-20 minutes).
6. Add basic CSS for a polished look (10 minutes).
7. Test with examples (5-10 minutes).

Time Management

• 0-10 min: read, clarify, plan.
• 10-60 min: build core.
• 60-80 min: edge cases and features.
• 80-90 min: test and polish.

The Takeaway

The machine coding round is a 90-minute build-a-UI round. They evaluate functionality, code quality, edge cases, UI/UX, and approach. Practice common questions (OTP, autocomplete, pagination, food ordering app). Read carefully, plan, build core first, handle edge cases, add CSS, and test. Time management is key.