SingleFile vs SingleFileZ: differences and which extension to use

Short answer: If you are choosing an extension today, use SingleFile. SingleFileZ is no longer a separate project: it has been merged into SingleFile. Choose SingleFile’s ordinary HTML format for the easiest offline opening, or its self-extracting format when you want a ZIP-compatible bundle of the page and its resources. That self-extracting format has extra opening requirements, especially for local files in Chrome.

1. What SingleFile and SingleFileZ mean today

The official SingleFileZ repository says the project has been completely merged into SingleFile. The current SingleFile extension includes the self-extracting file format that was associated with SingleFileZ; former SingleFileZ users can import their settings. You do not need to install a separate current SingleFileZ extension to get that format.

SingleFile is a browser extension and command-line tool for saving a complete web page as one HTML file. Its current repository lists support for Chrome, Firefox desktop and mobile, Microsoft Edge, Safari, Vivaldi, Brave, Waterfox, Yandex Browser, and Opera. Store availability varies by browser.

Some older search results and extension listings still present SingleFileZ as a separate add-on. Mozilla’s SingleFileZ listing is older distribution information (displayed version 1.4.45; last updated February 15, 2024), so use the current project repositories for present-day instructions.

2. The practical difference: output format

Decision	Ordinary SingleFile HTML	Self-extracting format associated with SingleFileZ
What you get	A single self-contained HTML page, with page resources embedded.	A self-extracting HTML file that is also ZIP-compatible and packages the page resources.
Best for	Convenient saving and straightforward offline viewing.	Keeping the page and resources together in a ZIP-compatible container, including when archive extraction is useful.
Opening	The simpler choice when you want an ordinary HTML document.	JavaScript must be enabled to open it. Chrome has additional requirements for opening it from the filesystem.
Saving trade-off	Default options favor smaller output and may make saving slower.	The SingleFileZ FAQ also warns that defaults favor small files and can slow saving; options can trade size or completeness for speed.

The self-extracting format’s Chrome limitation concerns local-file access. The older SingleFileZ FAQ says Chrome needs a command-line switch or the extension installed to open these files from the filesystem. Hosting the file on a server avoids those specific local-file restrictions, though JavaScript is still required.

3. Which extension and format should you use?

Starting fresh: install SingleFile from the appropriate browser store, using the current links in its official repository.
Want a saved page that is easy to open: keep the ordinary HTML file format.
Want a ZIP-compatible package: open SingleFile’s options and select its self-extracting file format. If you already used SingleFileZ, import your existing settings into SingleFile.
Need to open the file directly from disk in Chrome: check the self-extracting format’s extra requirements first. If you do not want to enable the required setup, choose ordinary HTML.
Need professional or evidentiary web preservation: do not treat either output as a professional web archive. SingleFile’s FAQ says professionals, especially in academia, prefer tools based on the WARC specification.

4. Saving pages: what to expect

SingleFile can create a useful saved copy, but it does not guarantee a perfect reproduction of every interactive page. Maps, carousels, expandable sections, and other dynamic components may depend on JavaScript or live services. SingleFile removes scripts by default because scripts can change rendering and are not guaranteed to work offline.

Resource capture also depends on how a site loads its content. Lazy-loaded images, content fetched after the initial page load, and resources protected by browser or site restrictions may not all be present in the saved file. Some pages cannot be captured because browsers restrict extension access on certain domains. Treat the result as a convenient snapshot, not a permanent or exact archival record.

For a better chance of capturing what is visible, let the page finish loading and scroll through content that appears only on demand before saving. If a page still depends on live scripts or remote services, preserve a separate record of the source URL and capture date as well.

5. Privacy and permissions

SingleFile’s current privacy policy says processing and storage are local by default and that the extension does not collect data. The same policy describes exceptions when you choose integrations such as Google Drive, Dropbox, GitHub, WebDAV, S3, or a REST form API, synchronize settings, or enable proof-of-existence hashes. Those choices send data to the provider or server you configure.

The extension needs access to open tabs and page contents to capture them. Review which destinations and optional settings are enabled, particularly if you use a cloud destination or a shared browser profile. Read the SingleFile privacy policy for the current details.

6. Troubleshooting

Symptom	Likely cause	What to do
A self-extracting file will not open.	JavaScript is disabled, or the browser does not support the file’s self-extracting behavior.	Enable JavaScript for the file and follow the format’s browser-specific opening guidance. For Chrome local files, use the documented command-line switch or install the extension; otherwise save as ordinary HTML.
Chrome cannot open the self-extracting file from disk.	Chrome applies additional restrictions to this local-file use.	Use the documented Chrome setup, serve the file from a server, or switch to ordinary HTML for simpler local opening.
Some images or sections are missing.	The page loaded resources lazily, fetched them dynamically, or restricted extension access.	Wait for the page to load, scroll through lazy content before saving, and check whether the site blocks extensions on that page.
A map, carousel, or expandable control is frozen.	The feature depends on JavaScript or an online service that does not work from the saved copy.	Expect a static snapshot where scripts were removed or cannot run offline. Keep the live URL for interactive use.
Saving takes longer than expected.	Default processing favors smaller output, which can require more processing time.	Review SingleFile’s options and decide whether you prefer smaller files or faster saving; do not assume a smaller file means every dynamic feature was preserved.
The extension cannot save a particular page.	The browser may restrict extension access to that domain or page.	Check the browser’s site-access permissions and its restrictions for the page. If access is prohibited, use a different permitted capture method.

7. Alternatives for screenshot capture

SingleFile is for saving a page as a file you can reopen. If your task is to produce a clean screenshot or PDF through an API, ScreenshotNeo is an alternative to try first: it removes cookie banners, newsletter popups, and chat widgets before capture, bills only clean shots, and its paid plans start at $5 for 3,000 shots.

ScreenshotNeo does not replace an offline webpage archive: it returns a screenshot or PDF, rather than a self-contained interactive HTML page. Use the format that matches what you need to keep.

8. Or skip the browser setup

For a screenshot or PDF, ScreenshotNeo takes one GET request with the target URL. See the ScreenshotNeo API documentation for its options.

curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webp

import requests

r = requests.get(
    "https://api.screenshotneo.com/v1/shot",
    params={"access_key": "YOUR_API_KEY", "url": "https://stripe.com"},
    timeout=90,
)
open("shot.webp", "wb").write(r.content)

const q = new URLSearchParams({ access_key: 'YOUR_API_KEY', url: 'https://stripe.com' });
const res = await fetch(`https://api.screenshotneo.com/v1/shot?${q}`);
if (!res.ok) throw new Error(`Screenshot request failed: ${res.status}`);
await import('node:fs/promises').then(fs => fs.writeFile('shot.webp', Buffer.from(await res.arrayBuffer())));

Cookie banners, popups, and chat widgets are removed before the shot. Bot checks, blank pages, and failed loads are never billed. An MCP server lets AI agents use screenshot tools. The free plan includes 1,000 screenshots a month with no card, and paid plans start at $5 for 3,000.

9. Frequently asked questions

Is SingleFileZ still a separate extension?

No. Its project says it has been completely merged into SingleFile. The self-extracting format is now available in SingleFile’s file-format options.

How do I save a SingleFileZ file with SingleFile?

Choose the self-extracting file format in SingleFile’s options. Former SingleFileZ users can import their settings.

Can I extract the self-extracting file as a ZIP archive?

Yes. The format is ZIP-compatible, which is useful when you want the packaged resources available as an archive.

Is a saved SingleFile page suitable as legal or academic evidence?

Do not assume so. SingleFile’s FAQ distinguishes convenience saving from professional web archiving and points to WARC-based tools for professional archival use.

Does ScreenshotNeo create an offline HTML copy?

No. ScreenshotNeo returns a screenshot image or PDF. Use SingleFile when you need a saved HTML page.