Data provenance, limits and privacy

Where metadata comes from

The DOI API retrieves a record from Crossref and returns a smaller structured result. AUN is an intermediary, not the publisher or a registration agency. The source URL and retrieval timestamp identify where and when metadata was retrieved; retrieval time is not publication time.

What the hash proves

The response includes a SHA-256 hash of the retrieved source bytes. It can support byte-level integrity comparisons. It does not establish that the metadata is correct, the paper is authentic or its scientific conclusions are valid. Provider responses can change between retrievals.

Coverage and retractions

Only Crossref records are covered. A DOI registered elsewhere can be absent. Reported update metadata may be incomplete. Missing updates do not establish that a paper has not been retracted. Consult the publisher and appropriate authoritative records for critical decisions.

Operational metrics

The application records API status, completion or interruption, backend response duration and whether a request was marked as an internal test. These metric events do not include the DOI, request URL, IP address, user agent or private test token. Unmarked traffic is not automatically a human visitor or an AI agent.

The DOI is transmitted to Crossref for execution. The site uses Vercel hosting and a Hostinger backend; infrastructure providers may retain their own operational logs independently. Application metrics use the server journal and its retention policy. This page does not promise that all infrastructure logs are anonymous.

Availability

The API remains a free research preview with shared limits and no uptime guarantee. It does not require a persistent database of lookup results or an account. No paid checkout is active.