This page aggregates measured, corroborated evidence: donors' iPhones recorded apps contacting this domain, every claim below was reported by separate accepted donations and published under a human verdict (later rows for an approved app inherit its verdict). A contact is a measurement, not an accusation — it does not show what data was sent.
gdx-api-mobileapps.costco.com
classified as first-party · 2
What our research panel found AI-drafted · human-reviewed
We ask several independent AI models the same question and publish their answers separately — cross-vendor agreement is evidence against fabrication, and disagreement is worth seeing. 3 of 3 models answered, overall confidence high. A human reviewed this domain's claims before anything here published.
Anthropic Claude — first-party
gdx-api-mobileapps.costco.com is a subdomain of costco.com, the app publisher's own domain, and the naming suggests a backend API endpoint serving the mobile apps, so it is first-party infrastructure. First-party API contact is inherent to app function and consistent with the declared collection of app interactions and diagnostics; I have no evidence it constitutes an undeclared data flow, though the specific data sent to this endpoint cannot be determined from the domain name alone.
OpenAI — first-party
The domain is under costco.com and is most likely a Costco first-party mobile API endpoint. The provided label declares several relevant app interaction, diagnostics, and browsing-related data categories, so the contact alone does not establish an undisclosed flow.
Google Gemini — first-party
The domain gdx-api-mobileapps.costco.com is a first-party subdomain owned and operated by Costco Wholesale for mobile app functionality. Standard first-party API communication does not inherently indicate undisclosed tracking or data sharing.
Apps measured contacting this domain
| App | Label gap | Donations | Contacts | Seen |
|---|---|---|---|---|
| Costco Wholesale | — | 4 | 24 | 2026-07-28 → 2026-07-29 |
The corpus grows one report at a time: donate your App Privacy Report — anonymous by design.
Think something here is wrong?
Evidence and research improve when people push back. Tell us what to re-check — a misattributed domain, an outdated classification, a claim about your own app — and a human will review it. Responses can take up to 30 days.