Shopify: "The alt value exceeds the maximum limit of 512 characters."
Image alt text is capped at 512 characters and rejected hard above it — while SEO title and description have no ceiling at all.
What you are seeing
The import is refused and the message names alt text, not the product it belongs to.
The alt value exceeds the maximum limit of 512 characters.
Why it happens
Alt text is the one text field in the product CSV we found a hard ceiling on. 513 characters is refused outright. This surprises people because the fields that LOOK like they should be capped are not: we stored a 5,000-character SEO description and a 71-character SEO title verbatim, with no error and no truncation.
Alt text this long is almost always generated — a description pasted into the alt column by a supplier feed or a bulk-edit script, rather than written for a screen reader.
How to fix it
- Find the offending rows before you upload: sort or filter your Image Alt Text column by length and look at anything over 512 characters.
- Truncate to something that describes the image. Alt text is for someone who cannot see the picture; a paragraph of marketing copy is failing them as well as failing the import.
- If the alt column was filled from your description column by mistake, clear it entirely rather than truncating — an empty alt is better than 512 characters of the wrong thing.
Where this came from
We broke a real Shopify store on purpose to answer these questions, and kept what it said. Nothing on this page is quoted from documentation.
- SEO title and description are stored verbatim: 71 characters came back as 71, and 5000 came back as 5000 — no error, no truncation, no ceiling found at all. Image alt text is the opposite: 513 characters is a hard rejection.
What we did not measure. We tested 71, 512 and 513 characters. We did not test every field in the CSV for a ceiling, so this page says what alt text does and does not claim anything about columns we did not probe.
Observed 2026-09-04. The store this was measured on has since been deleted, so these answers are an archive rather than something we re-run — we would rather tell you the date than imply it is checked continuously.
Check your file before you upload it
The Pre-Flight Report reads your supplier file and names every blocker, with the row it is on, before you go near an importer. It is free, it needs no account, and it does not send your file to a model.