SingleFile

SingleFile is an open-source browser extension that saves a complete web page — including all styles, images, fonts, and scripts — into a single self-contained HTML file. For OSINT investigators, digital forensics professionals, and researchers who need to preserve web evidence in a portable, verifiable format, SingleFile provides one of the most complete and self-contained page capture options available.

Unlike standard browser save functions that create a folder of separate files (HTML plus a directory of assets) or PDF exports that lose interactivity, SingleFile embeds all page resources directly into a single HTML file using data URIs. This makes the saved page truly portable — the single file opens in any browser without depending on any external servers, CDNs, or linked assets that might change or disappear over time.

For evidence preservation, the self-contained nature of SingleFile captures is significant: a standard HTML save might reference images stored externally, meaning the "saved" page is incomplete if those servers go offline or the content changes. SingleFile captures everything inline, creating an accurate snapshot of exactly what was visible at capture time.

SingleFile works across all major browsers (Chrome, Firefox, Edge, Safari) via extension, and a command-line version is available for automated or server-side capture workflows. The CLI version enables integration into investigation workflows, allowing batch capture of multiple URLs programmatically.

The captures produced by SingleFile preserve the visual layout and interactive elements more faithfully than PDF exports, which can misrender complex layouts. Social media profiles, interactive dashboards, and complex web applications often look correct in SingleFile captures but render poorly in PDF.

For additional evidentiary support, SingleFile captures can be supplemented with hash values (calculated before and after storage) and timestamped using tools like Hunchly or verified timestamp services. While SingleFile itself doesn't embed cryptographic verification, the output file can be hashed and notarized using separate tools.

Installation is available through each browser's extension marketplace. The command-line tool is available via npm: run "npm install -g single-file-cli" for server-side capture capabilities.

Pair SingleFile with Hunchly or Webrecorder for investigations requiring comprehensive, audit-grade web content preservation.