ISO 28500:2017 specifies the WARC file format:

- to store both the payload content and control information from mainstream Internet application layer protocols, such as the HTTP, DNS, and FTP;

- to store arbitrary metadata linked to other stored data (e.g. subject classifier, discovered language, encoding);

- to support data compression and maintain data record integrity;

- to store all control information from the harvesting protocol (e.g. request headers), not just response information;

- to store the results of data transformations linked to other stored data;

- to store a duplicate detection event linked to other stored data (to reduce storage in the presence of identical or substantially similar resources);

- to be extended without disruption to existing functionality;

- to support handling of overly long records by truncation or segmentation, where desired.