Outlook Web Inbox Count

A lightweight browser extension that adds the total number of items next to the Inbox label in Outlook Web, so you can see at a glance how many emails are sitting in your inbox without having to open the folder.

By default Outlook Web only shows the unread count; this extension adds the total item count alongside it.

Install

• Chrome / Edge / Brave: Chrome Web Store listing
• Firefox: load as a temporary add-on via about:debugging (the extension is Manifest v3 and includes a browser_specific_settings.gecko entry).

The extension runs on:

• https://outlook.office.com/*
• https://outlook.office365.com/*
• https://outlook.cloud.microsoft/* (the current domain as of 2026)

How it works

A content script (content.js) watches the Outlook Web DOM and the page title for the inbox item count, then injects a small span next to the Inbox label showing the number. It uses:

• A MutationObserver (scoped to title and data-folder-name attribute changes) to react to navigation and refresh events.
• Multiple fallback selectors and regex patterns to cope with different Outlook Web versions and locales.
• A 1-second throttle and a 15-second periodic safety check to keep CPU usage low.

If the count cannot be determined, the extension shows (-) in grey rather than nothing, so it is clear the extension is running.

Development

The extension is three files plus icons - no build step is needed.

1. Clone the repo.
2. In Chrome, go to chrome://extensions, enable Developer mode, and click Load unpacked. Select the project directory.
3. Open Outlook Web and check the DevTools console for log lines starting with Outlook Inbox Count Extension.

When a new Outlook Web version breaks detection, the most likely places to look are findInboxElement() and findTotalItems() in content.js - the selector and regex lists there are the extension's knowledge of how Outlook Web renders the inbox label and count.

Releasing

The release process is automated via publish.sh, which builds the zip from manifest.json, uploads it to the Chrome Web Store, and submits it for review. The routine workflow is:

1. Bump version in manifest.json and add a changelog entry in the header of content.js.
2. Run ./publish.sh.

See PUBLISHING.md for the full reference, including the one-time OAuth setup and troubleshooting.

Project layout

manifest.json     Chrome extension manifest (v3)
content.js        Content script - all the logic lives here
icon16/64/128.png Extension icons
publish.sh        Build + upload + publish automation
PUBLISHING.md     Chrome Web Store release process reference
.env              Credentials for publish.sh (gitignored)

Author

Giorgio Gilestro - https://lab.gilest.ro