Design
Online Survey / Form Builder
Design a form-building platform (like Google Forms) supporting custom questions, conditional logic, and response analytics.
This is a Low-Level Design (LLD) problem. New to LLD vs HLD? Start here.
01 - Why interviewers ask this
Conditional branching logic is the crux here — interviewers check whether your design evaluates rules cleanly instead of hardcoding "if question 3 then show question 5" logic.
02 - Where this system exists in the real world
You interact with this design every day.
Google Forms / Typeform-style form builders
Customer feedback and NPS survey tools
HR/onboarding intake form systems
03 - What you'll master
Solve this once. Know it forever.
Model multiple question types via Strategy
Implement conditional/branching logic between questions
Design incremental analytics aggregation
04 - What you'll design
6 functional · 2 non-functional requirements.
Build a form with multiple question types (text, multiple-choice, rating, date)
5 more requirements inside
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05 - Companies that ask this
You may face this exact question in your next interview.
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