Interview Q&A / System Design
System Design interview questions
Caching, scaling, databases and classic design problems for beginners.
Prefer rapid revision? Practise System Design short interview answers →
- What is the difference between offset and cursor pagination?
Offset pagination uses page number and size (LIMIT 20 OFFSET 40), which is simple but slow on deep pages and shifts when rows change. Cursor pagination continues after the last item seen, so it stays fast and stable.
BeginnerQuick answer1 min read - Why is returning a total count with every page expensive, and what are the alternatives?
COUNT(*) over a large filtered table scans many rows on every request. Alternatives are returning only has_next, using approximate counts, caching the count, or showing 'more than 1,000' instead of an exact total.
IntermediateQuick answer1 min read