Memento - Time Travel for the Web

Memento wants to make it as straightforward to access the Web of the past as it is to access the current Web.

To facilitate that, the Memento protocol was specified in RFC 7089. A more gentle entry point is provided by the Introduction to Memento. In essence, the Memento protocol adds a time dimension to HTTP. Inspired by HTTP content negotiation, the protocol introduces the notion of datetime negotiation to allow a client to request a version of a resource as it existed at a specified time in the past. The protocol is supported by all major web archives, including the Internet Archive. As described in Resource Versioning and Memento, it also neatly aligns with a common pattern for versioning web resources, like the one used by wikis. But no major wikis have implemented support for the protocol yet, and that's unfortunate because, otherwise, with a Memento-savvy client, one would be able to seamlessly navigate across web archives and resource versioning systems. Basically navigating the web as if it were 1999.

The Memento protocol resulted from a collaboration between the (no longer existing) Prototyping Team of the Research Library of the Los Alamos National Laboratory and the Web Science and Digital Library Research Group of the Computer Science Department of Old Dominion University. The work was supported by funding from the Library of Congress and the Andrew W. Mellon Foundation.

This website launched in 2019 and was operated and funded by the Research Library of the Los Alamos National Laboratory. As a result of a managerial decision, the site was taken down towards the end of 2025. The current static site, brought online in 2026, contains resources resurrected from the original site that provide information about the Memento "Time Travel for the Web" protocol and related work. It is operated on a volunteer basis and is hosted as Github Pages. The site used to provide two services that were necessarily discontinued as a result of the forced migration:

• The Time Travel service was a Memento aggregator that allowed searching across a wide range of public web archives, providing both a user interface and an API. It operated between 2015 and 2025 as an official service of the Research Library of the Los Alamos National Laboratory. The paper Routing Memento Requests Using Binary Classifiers provides some technical background about its design and operation.
• The Robust Links service created annotated links compliant with the Robust Links specification, providing both a user interface and an API. The paper Robustifying Links To Combat Reference Rot describes the service and compares it to other attempts to combat reference rot.

The site also provided access to the What Did It Look Like? service operated by the Web Science and Digital Library Research Group of Old Dominion University. It allowed nominating a URL of interest via Twitter and would return a list of Mementos over the years for that URL, retrieved from various web archives. The service was discontinued around 2021.

Some originators of the protocol are still lurking around on the Memento Development Group mailing list. So, if you feel like picking up the thread, post your ideas and questions there.