What it is
A byte-order mark or stray invisible characters at the start of a file can disrupt parsing, push output before the head, or break scripts. Files should be clean UTF-8 without a BOM. Hidden characters corrupt markup. Can break parsing/JSON-LD. Strip BOM/invisibles.
Why does bom/invisible characters matter for AI search?
Can break parsing/JSON-LD.
How do you fix it?
Strip BOM/invisibles.
How do you find it on your site?
- Check source files for a BOM or invisible characters, especially at the start.
- Re-save files as UTF-8 without BOM.
- Strip stray zero-width or control characters.
- Re-validate the document.
Which ranking and citation factors does it touch?
A BOM or invisible characters can corrupt parsing and output. Clean encoding keeps the document well-formed.
What is the impact?
Low. Inferred.
What is the evidence?
Clean markup parses reliably. Google Search Central, Structured data general guidelines
Frequently asked questions about bom/invisible characters
What does "BOM/invisible characters" mean?
Hidden characters corrupt markup.
How do you fix bOM/invisible characters?
Strip BOM/invisibles.