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WARCs, screenshots, and PDFs: what's the difference?

Jamie Hoyle

In the digital era, web archiving has become an essential aspect of preserving your digital communications for presentation to regulators and legal teams. Whilst archive formats such as website screenshots and PDFs have been used for a long time, they lack the ability to capture the interactivity of web pages. In turn, this could mean that you are missing vital information from your marketing and compliance preservation operations. This is where the WARC file format and MirrorWeb's dynamic replay capability come in.

The WARC File Format

The WARC (Web ARChive) file format is a container format for storing web pages, associated metadata, and multimedia content. Unlike website screenshots and PDFs, every asset collected as part of a WARC is time-stamped and immutable, meaning that it cannot be altered. This ensures that all captured content remains authentic and accurate. WARC is an ISO standard, and contains all the information required to prove regulatory compliance. For more information on the WARC file format and how it meets regulatory compliance requirements, access Deloitte’s report on the WARC format here.

The MirrorWeb Difference

MirrorWeb's dynamic capture and replay capabilities use the WARC file format to capture and preserve webpages. This technology provides a more comprehensive and accurate representation of a website, capturing everything from media content to APIs, thus providing a complete snapshot of the website at a particular time. With MirrorWeb, users can access archived websites and interact with them as if they were accessing the live site. This is a significant improvement over website screenshots and PDFs, which only provide a static view of a website. We can then prove compliance to regulators and legal teams through granting direct access to the web archives, providing our comprehensive set of logs and reports, or by generating a signed and timestamped PDF of the individual page that requires archiving.

Comparison to Website Screenshots and PDFs

Website screenshots and PDFs are still widely used for web archiving, but they have limitations. Website screenshots only capture what is visible on the screen at a particular moment, and they do not capture any dynamic content such as pop-ups, accordion content, and animations. PDFs, on the other hand, capture a static version of the website, but still do not capture any interactive content. With modern websites often containing dropdowns and accordions, these limitations make website screenshots and PDFs less effective for web archiving than the WARC file format and MirrorWeb's dynamic website capture capabilities.


Web archiving is an essential aspect of preserving your organization’s history, and the WARC file format provides the most comprehensive and accurate way of achieving this. Our capture and replay capabilities capture the dynamic nature of web pages, providing a complete snapshot of the website at a particular time. This is a significant improvement over website screenshots and PDFs, making web archiving more effective and reliable.

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