Top 3 Inp Interview Questions
Browse 3 real-world technical and behavioral interview questions about Inp. Review scenarios, edge cases, and architectural best practices.
INP went from 150ms to 400ms the week a marketing tag was added. Marketing says the script is async and cannot be the cause. How do you prove it either way and fix it?
Async controls when a script downloads, not what it does to the main thread once it executes, so an async tag can still block interaction handling. Prove it with field data attributed to the interaction: INP breaks into input delay, processing and presentation, and each points elsewhere. Then move the work off the critical path.
How do you resolve unacceptable INP degradation caused by massive, synchronous JavaScript execution blocking the main thread?
Evaluate the candidate's understanding of the JavaScript event loop, rendering pipeline, and modern techniques for yielding to the main thread to improve INP. Use this frontend answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects performance to the point an interviewer is testing.
Field data says your page has an INP of 400 ms. How do you find the cause and fix it?
Split the interaction into input delay, processing time and presentation delay, then attribute a real interaction from the field rather than guessing. Most of the budget is usually spent before your handler runs or after it returns, so yielding and cutting rendering cost beats optimising the handler.