Overview

Amazon Seller Central returns error 18028 when a bulk upload—whether a flat‑file feed or an XML submission—contains missing mandatory fields or data that does not match the required format. The error blocks the feed, preventing catalog or order updates, so sellers who rely on batch processing must resolve it quickly to keep operations flowing.

Key Points

• Root cause — The system flags the submission when any required element is absent or when a value fails validation against Amazon’s schema.
• Affected processes — Error 18028 can appear during inventory uploads, price updates, order acknowledgments, or any other bulk operation that uses Seller Central’s feed tools.
• File‑type dependency — Flat‑file templates (tab‑delimited text) and XML feeds each have distinct sets of required columns or elements, so the same mistake may surface in different formats.
• Typical trigger — A missing SKU, an empty price field, or a date entered as “MM/DD/YYYY” instead of the ISO‑8601 format will immediately cause the error.
• Resolution path — Comparing the submitted file against the official template or XSD schema usually reveals the exact field that needs correction, allowing a single re‑upload to clear the batch.

How Error 18028 Is Triggered

1. Submission intake — When a seller uploads a feed, Amazon’s validation engine reads every row or XML node and maps it to the internal data model. Example: a 5,000‑row inventory file is loaded into a temporary staging table.
2. Field verification — The engine checks each column or element against a list of mandatory attributes defined for that feed type. Example: the “price” column must contain a numeric value with two decimal places; a blank entry fails this rule.
3. Format enforcement — Values are examined for correct data types, length limits, and accepted enumerations. Example: a “condition_type” field that contains “newish” instead of the allowed “new”, “used”, or “refurbished” triggers a failure.