How would you prevent XSS in a React app that must render user HTML?
PICTURE THIS: BROWSER VS ATTACKER
Simple meaning
I run the HTML through a sanitizer with an allowlist of tags and no script, iframe, or event handlers.
WHY — Security instead of guessing?
Why interviewers care about Security:
question about Security.
trade-offs, and what you would actually do on a Frontend project - not buzzwords.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1I run the HTML
through a sanitizer with an allowlist of tags and no script, iframe, or event handlers.
- 2I still set a
tight CSP as defense in depth.
- 3Markdown with a sanitizing
renderer is safer than dumping CMS HTML raw.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
I run the HTML through a sanitizer with an allowlist of tags and no script, iframe, or event handlers. I still set a tight CSP as defense in depth.