The HTTP Framework for Time-Based Access to Resource States, also known as the Memento framework, is a method of denoting and obtaining historical revisions of HTTP resources, such as a web pages or files accessible by URL. Development of the framework was initiated as a project of the United States National Digital Information Infrastructure and Preservation Program (NDIIPP). It was funded with the aim of making Web-archived content more easily discoverable and accessible to the public.
The Memento project announced the shutdown of its hosted TimeTravel service on 5 September 2025.
Technical description
Memento is defined in RFC 7089: HTTP Framework for Time-Based Access to Resource States -- Memento as an implementation of the time dimension of content negotiation.Berners Lee, Tim. "Web Architecture: Generic Resources". World Wide Web Consortium (W3C). 1996. http://www.w3.org/DesignIssues/Generic HTTP accomplishes negotiation of content using headers that allow clients and servers to find content that the user desires.
+ Dimensions of Content Negotiation Provided by HTTP Request Header Response Header Dimension Examples Reference Accept Content-Typemedia type of the representation, can include character set text/html; charset=utf-8 text/plain image/png (obsoletes ) Accept-Language Content-Languagelanguage of the representation en-US, en cs (obsoletes ) Accept-Encoding Content-Encodingmedium, typically compression, that the content has been encoded with compress gzip deflate (obsoletes ) Accept-Datetime Memento-Datetimetime of the representation Fri, 15 Aug 2014 13:43:03 GMT
The header provided by HTTPRFC 7232: Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests does not necessarily reflect when a particular version of a web page came into existence. Also, the header may not exist in some cases. To provide more information, the header has been introduced to indicate when a specific representation of a web page was observed on the web.Nelson, Michael L. "2010-11-05: Memento-Datetime is not Last-Modified". Web Science and Digital Libraries Research Group. November 5, 2010. http://ws-dl.blogspot.com/2010/11/2010-11-05-memento-datetime-is-not-last.html
Usage
Copies of page can be found by simply navigating, in a web browser, to a link formatted, replacing urltoarchive with the full URL of the page desired.
JSON description of a Memento: http://timetravel.mementoweb.org/api/json/YYYY/urltoarchive http://timetravel.mementoweb.org/api/json/YYYYMM/urltoarchive http://timetravel.mementoweb.org/api/json/YYYYMMDD/urltoarchive http://timetravel.mementoweb.org/api/json/YYYYMMDDHH/urltoarchive http://timetravel.mementoweb.org/api/json/YYYYMMDDHHMM/urltoarchive Or redirect to a Memento with a datetime that is close to a desired datetime: http://timetravel.mementoweb.org/memento/YYYY/urltoarchive http://timetravel.mementoweb.org/memento/YYYYMM/urltoarchive http://timetravel.mementoweb.org/memento/YYYYMMDD/urltoarchive http://timetravel.mementoweb.org/memento/YYYYMMDDHH/urltoarchive http://timetravel.mementoweb.org/memento/YYYYMMDDHHMM/urltoarchive
References
External links Memento Project The When of the Web - Extensive information about the proposal and experiment is available in the November 2009 paper Memento: Time Travel for the Web http://lanlsource.lanl.gov/hello http://www.cdlib.org/cdlinfo/2010/02/04/web-archive-discovery-memento-implementation-meeting/