Overview

Sellers uploading product information to Amazon may encounter error 99057 when a field in their feed exceeds the byte‑size limit set for that attribute. The issue appears during flat‑file or API feed processing and can halt updates to the offending attribute. Resolving the problem promptly prevents delays in listing creation and keeps product pages complete.

Key Points

• Trigger condition — The error fires when any attribute value in a submitted feed is longer than the maximum byte length allowed for that field.
• Partial acceptance — Amazon discards only the oversized entry; all other correctly sized fields continue to process normally.
• Byte vs. character count — Characters such as “é”, “ü”, or Chinese glyphs consume multiple bytes, so a string that looks short may still breach the limit.
• Attribute‑specific caps — Each catalog attribute—title, bullet, description, search term, etc.—has its own ceiling that varies by product category.
• No health penalty — The error does not affect account health metrics, but it can leave listings with missing or outdated information.

How the Validation Works

1. Feed ingestion — When a seller submits a flat file, SP‑API feed, or third‑party generated upload, Amazon’s ingestion engine parses each row and maps columns to catalog attributes. Example: a row for ASIN B012345678 includes a “BulletPoint1” column with 350 characters.
2. Byte‑length check — The system converts each field to UTF‑8 and measures the resulting byte count, comparing it against the predefined limit for that attribute. Example: the “BulletPoint1” limit for the “Home & Kitchen” category is 250 bytes; the 350‑character string translates to 312 bytes, exceeding the cap.
3. Error flagging — If the byte count surpasses the threshold, Amazon logs error 99057, records the attribute name and its maximum byte allowance, and omits the offending value from the update. Example: the feed report shows “BulletPoint1 – exceeds 250‑byte limit (312 bytes provided).”