Safari storage quota accuracy

[joshkel]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Storage_API/Storage_quotas_and_eviction_criteria

What specific section or headline is this issue about?

How much data can be stored? -> Safari

What information was incorrect, unhelpful, or incomplete?

I believe that the information on Safari's limits may be inaccurate.

Relevant portions from MDN:

Starting with macOS 14 and iOS 17, Safari allots up to around 20% of the total disk space for each origin. If the user has saved it as a web app on the Home Screen or the Dock, this limit is increased to up to 60% of the disk size...

Safari also enforces an overall quota that stored data across all origins cannot grow beyond: 80% of disk size for each browser and web app, and 15% of disk size for each non-browser app that displays web content.

This change was made as part of #28510.

What did you expect to see?

According to https://www.webkit.org/blog/14403/updates-to-storage-policy/:

• For a browser app, the origin quota is up to 60% of the total disk space.
• For other apps, the origin quota is up to 15% of the total disk space.

An app is a browser app if it can be set as default browser.

I understand this to mean that a "browser app" is Chrome, Firefox, etc. I assume that "other apps" therefore refers to embedded WebViews in any other app.

The overall quota is the storage limit of all origins...

• For a browser app, overall quota is up to 80% of the total disk space.
• For other apps, overall quota is up to 20% of the total disk space.

When a web app is running standalone (as Home Screen Web App on iOS or Web App added to dock on macOS), it has the same origin quota and overall quota as when it is opened in a browser app.

I understand this to mean that Apple uses "browser app" to refer to native iOS apps like Safari, Chrome, or Firefox, and "web app" to mean websites running standalone (PWA-style).

If my understanding is correct, there are two discrepancies between this article and MDN:

• MDN seems to state the numbers backwards (60/15 - 80/20 versus 60/20 - 80/15).
• MDN understands this to be a distinction between websites running standalone (PWA-style) and websites running in a browser, while I understand the WebKit article to describe a distinction between websites running in a browser and websites running in non-browser apps' WebViews.

Do you have any supporting links, references, or citations?

https://www.webkit.org/blog/14403/updates-to-storage-policy/

#28510 references this WebKit article, which makes me wonder if either it or I am misunderstanding the article.

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/api/storage_api/storage_quotas_and_eviction_criteria
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/Storage_API/Storage_quotas_and_eviction_criteria
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md
• Last commit: 4d929bb
• Document last modified: 2025-03-13T12:48:23.000Z