HTML pulled from a server response or a scraper usually arrives as one dense line, hard to read. Here's why re-indenting it helps.
What's invisible without indentation
An unclosed <div>, or a stray <p> sitting inside a </table> where it doesn't belong, is extremely hard to spot in a single dense line of HTML. Indenting by tag hierarchy makes exactly which tag sits inside which visually obvious.
Common use cases
This is a big help when analyzing HTML pulled from scraping another site, debugging minified server-rendered output, or reviewing an inline-style-heavy HTML block like an email template.
What to check afterward
Indentation is just a visual cleanup โ actually verifying that tags are properly paired or that there are no duplicate ids still needs a dedicated HTML validation tool.