Overview

Error 90177 is a product listing validation error that occurs when a value submitted for a specific attribute does not conform to Amazon's required formatting pattern. This error prevents sellers from creating or updating listings until the offending attribute value is corrected. Understanding how pattern constraints work can help sellers resolve this issue quickly and avoid repeated feed rejections.

Key Points / What Sellers Need to Know

• Pattern constraint violation - Amazon enforces specific formatting rules (patterns) for certain listing attributes, and Error 90177 fires when a submitted value fails to match the expected format.
• Attribute-specific - The error message identifies which attribute triggered the violation and which pattern rule was broken, making it easier to pinpoint the problem.
• Common in bulk uploads - This error frequently appears when sellers use flat files or feed submissions where manual data entry can introduce formatting mistakes.
• Blocking error - Listings will not be created or updated until the attribute value is corrected to match the required pattern.

How Pattern Constraints Work

Amazon assigns formatting patterns to many listing attributes to ensure data consistency across its catalog. These patterns are essentially rules that define what characters, lengths, and structures are acceptable for a given field. For example, a UPC field might require exactly 12 numeric digits, or a color attribute might prohibit special characters. When a seller submits a value that violates one of these rules, the system rejects the submission and returns Error 90177 along with the attribute name and the pattern it was expected to follow. The error message template reads: "Value does meet pattern constraint for attribute '{attribute_name}'. Should not match the pattern '{pattern}'." This tells the seller exactly which field to fix and what formatting rule to reference.

Common Causes and Examples

Several situations frequently trigger this error. Submitting letters in a numeric-only field — such as including dashes in a GTIN or EAN code — is a typical cause. Extra whitespace, special characters, or incorrect casing in fields with strict formatting can also trip the validation. Sellers working with flat file uploads often encounter this error when copying data from spreadsheets that introduce hidden characters or formatting artifacts. Another common scenario involves submitting values that exceed the maximum allowed length for an attribute, or using a format that belongs to a different marketplace (for instance, submitting a European VAT number format in a US-specific field).