TDM-Reservation header

Definition: Text and data mining (TDM) is automated analysis of digital text and data to produce information such as patterns. TDM-Reservation is an HTTP response header that signals whether the rights holder reserves TDM rights for the returned web resource.

As of 17 October 2026, the W3C-hosted TDM Reservation Protocol report, dated 10 May 2024, specifies this header. It is a Community Group report, outside the W3C Standards Track.

Key facts

• The protocol report places tdm-reservation in the response to a GET or HEAD request, with an optional tdm-policy header.
• Article 4(3) of Directive (EU) 2019/790 makes the mining exception conditional on rights holders having left the relevant use unreserved, and identifies machine-readable means for publicly available online content.
• The Community Group's September 2025 meeting notes explain that a reservation can accompany a policy describing how mining rights may be obtained.

What do the values mean?

The report's reservation property definition specifies a boolean value, expressed as a digit:

• 1 means TDM rights are reserved. A linked policy may explain how to obtain authorization from the rights holder.
• 0 means TDM rights are not reserved. In the protocol, the mining software can proceed without contacting the rights holder about that reservation.

Other values are protocol errors. The software must treat the property as unset. The literal value unset therefore describes a processing state; the defined header values remain 0 and 1.

What does the header look like?

The report's HTTP response examples include a reservation accompanied by a policy URL. These header lines reproduce that combination:

tdm-reservation: 1
tdm-policy: https://provider.com/policies/policy.json

A TDM policy describes the mining licences available from a rights holder. The policy header is optional, so a reservation can also appear alone. For a reservation value of 0, the report says mining software should leave any accompanying policy unprocessed.

The example concerns the resource returned in that response. The same header mechanism works independently of the resource's content format; the report also illustrates a reservation on an image response.

How is the effective reservation checked?

The report's processing priority rules require mining software to check the site's /.well-known/tdmrep.json file before scraping. A reservation supplied in an HTTP response overrides values obtained from that file. Embedded TDM metadata in the fetched HTML, EPUB or PDF resource then overrides earlier values.

At each step, absent properties leave existing values in place. Consequently, a response without the header can still have a reservation supplied through another protocol mechanism. The report recommends using only one technique.

For a website review, this order provides a concrete checklist: inspect the resource's GET or HEAD response, then compare its headers with the site file and any embedded TDM metadata. Reading the response header alone can miss a later override.

Related terms

• TDM Reservation Protocol
• TDM-Policy header
• tdmrep.json
• When can a rights holder reserve commercial text mining rights?

FAQ

Does a reservation prevent all scientific research mining?

Article 4(4) of Directive (EU) 2019/790 preserves the application of Article 3. That separate exception concerns scientific research mining by research organisations and cultural heritage institutions with lawful access.

Can I use true instead of 1?

The protocol's value definition specifies 1 and 0. If you send true, it falls under the rule for other values: a protocol error processed as an unset reservation.

Sources

1. W3C Community Group, "TDM Reservation Protocol (TDMRep)", 10 May 2024
2. European Parliament and Council, "Directive (EU) 2019/790", 17 April 2019
3. W3C Community Group, "Notes, September 30th, 2025", 1 October 2025

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