How ListLoco Quality Gates Work

ListLoco applies a set of deterministic, testable quality gates to every localized Amazon DE product listing. This page explains which official sources each gate is based on, what it checks, and how it is maintained.

Official Sources

Each gate is derived from publicly available policy and regulatory documentation. The current sources are:

• Amazon DE Seller Central — Amazon Germany's listing style guidelines, title character limits, and restricted-term policies. ListLoco tracks the guidelines published at sell.amazon.de and Seller Central help pages.
• EU General Product Safety Regulation (EU) 2023/988 — EUR-Lex — The GPSR requires product listings sold in EU markets to include manufacturer information, EU Responsible Person details, and safety information in the local language.

Quality Gates

All gate thresholds and rule sets are defined in the ListLoco rules module (src/rules/amazon-de.js) and gate configuration (src/config/gates.js). These are the single source of truth — the values below are descriptions, not duplicates.

Title character limit

Checks whether the localized title exceeds the character limit for the Amazon DE marketplace. The limit is defined in src/rules/amazon-de.js under titleMaxLength. See the Amazon DE Listing Rules Reference for the current value. Titles that exceed the limit are flagged as violations before the response is returned.

Banned and restricted words

Scans the localized title and description for terms that Amazon DE disallows in product listings. The list is maintained in src/rules/amazon-de.js under bannedWords. Categories currently covered include superlatives and ranking claims, absolute claims, and health and medical efficacy terms. See the rules reference for the current term set (22 terms as of last review).

Required attributes

Verifies that mandatory listing fields are present in the output. The required fields are defined in src/rules/amazon-de.js under requiredAttributes. A missing field triggers a required-attributes violation in the API response.

Model number and unit preservation

Detects numeric values, model numbers (e.g. AB-1200), and measurement units (e.g. kg, m) in the source text and verifies they appear unchanged in the localized output. A mangled or dropped model number is a hard failure regardless of how small the change is lexically. Implemented in src/gates/preservation.js.

Back-translation divergence

Re-translates the localized output back to the source language using the same dictionary, then measures lexical divergence between the round-trip result and the original source. If divergence exceeds the threshold in src/config/gates.js (BACK_TRANSLATION_DIVERGENCE_THRESHOLD), the gate flags the listing. The preservation check also runs independently on the back-translated result, so a mangled model number blocks the listing regardless of the overall lexical score. This means the threshold is never tuned upward to mask a preservation failure.

How These Gates Differ from Machine Translation

Generic machine translation produces fluent text but does not enforce marketplace rules. A listing translated without rule enforcement may produce garantiert or Bestseller in the output — both restricted terms on Amazon DE. A number like 8.5 kg may be reformatted or dropped during translation.

ListLoco's gates run after translation and block output that violates the rule set, ensuring that what reaches the marketplace matches what the rules require. For a side-by-side comparison, see DeepL and Google Translate vs ListLoco for Amazon DE.

How the Gates Relate to EU GPSR

EU GPSR (Regulation (EU) 2023/988) requires product listings on EU marketplaces to include the manufacturer's name and address, EU Responsible Person details, and product safety information in the local language. The required-attributes gate verifies that these structured fields are present in the API output. Populating the fields with accurate content is the seller's responsibility.

Coverage and Maintenance

The rule set covers Amazon DE English-to-German product listing localization. Rules are reviewed when Amazon publishes updated listing guidelines or when Seller Central documentation changes. The update cadence depends on how frequently Amazon modifies its published policies.

All gates are deterministic and covered by automated tests in test/ (run with node --test). A gate change requires a test update before it can be merged.

Last reviewed: 2026-06-28 · Coverage: Amazon DE, English → German