Inbox Search Is Now Available on Microsoft AppSource

Inbox Search — a free Outlook add-in that uses on-device AI for fast, semantic email search — has been approved by Microsoft and is now live on AppSource. You can install it today from the marketplace or from within Outlook.

What is Inbox Search?

Inbox Search is an Outlook add-in that builds a local fingerprint index of every email in your primary mailbox. It combines semantic AI embeddings with TF-IDF keyword matching to let you find emails by meaning — not just exact words.

Search "budget discussion from last quarter" and get results even if none of your emails contain that exact phrase. Search a specific name or project code and it surfaces the exact match first. Both approaches work together in a single query.

What makes it different

• On-device AI. The AI model runs entirely in your browser via Transformers.js and WebAssembly. No email content is ever sent to a server. There is no cloud processing, no tenant admin grant required, and no enterprise license needed.
• Hybrid search. Combines semantic understanding with precise keyword matching. Natural language queries and exact term searches both work — in the same search box.
• Fast results. Returns results in under 500ms for a mailbox of 10,000 emails. Results appear as you type and are ranked by relevance.
• Searches all folders. Inbox, Sent, Drafts, subfolders — everything in your primary mailbox is indexed and searchable from one place.
• Zero configuration. Install it, sign in with your Microsoft account, and start searching. The index builds automatically in the background.

How to install

There are two ways to get Inbox Search:

• From AppSource: Visit the Inbox Search listing on Microsoft AppSource and click "Get it now."
• From within Outlook: Click the "Get Add-ins" or "Add-ins" button in your Outlook ribbon, search for "Inbox Search," and install it directly.

Inbox Search works with Outlook on the web, new Outlook for Windows, and classic Outlook for Windows and Mac. It requires a Microsoft 365 or personal Microsoft account.

What happens after install

When you first open Inbox Search, it downloads a small AI model (~34 MB, one-time) and begins indexing your mailbox in the background. You can start searching right away — results improve as the index builds. The entire index is stored locally in your browser's storage and is deleted if you uninstall the add-in.

Privacy by design

Inbox Search was built with a simple rule: your email content never leaves your device. The only network calls are to Microsoft Graph (to read your emails for indexing) and to download the AI model on first run. There are no analytics, no tracking cookies, and no account creation. Read the full privacy policy for details.