Get Sendasta Running in Minutes
Installing just for yourself takes about 3 minutes. Rolling it out to your whole team takes about 5 — no AppSource approval, no end-user action needed.
Install Sendasta for yourself
Takes about 3 minutes. No admin access required — works on Outlook web and desktop.
Download sendasta-manifest.xmlSmall XML file — your browser will save it to your Downloads folder
Download the Sendasta manifest file
Click the download button above to save sendasta-manifest.xml to your computer. You'll need this file in the next step.
Open Outlook on the web
Go to outlook.office.com and sign in with your Microsoft 365 account. (Desktop Outlook also works — the steps are the same.)
Open the Add-ins manager
Click the Apps icon in the Outlook toolbar, then click "Get add-ins". This opens the "Add-ins for Outlook" window.
Upload the manifest file
In the left pane, select "My add-ins". Scroll to the bottom to find "Custom Add-ins". Click "Add a custom add-in" → "Add from file", then select the sendasta-manifest.xml file you downloaded.
Confirm the installation
Outlook will show a confirmation prompt — click "Yes" to confirm. Sendasta appears immediately in your compose toolbar. Open a new email to see it.
Deploy to your entire organization
As an IT administrator, you can roll Sendasta out to your whole Microsoft 365 organization in minutes — no end-user action needed.
Open the Exchange Admin Center
Navigate to admin.exchange.microsoft.com and sign in with your Microsoft 365 administrator account.
Go to Organization > Add-ins
In the left navigation, expand "Organization" and select "Add-ins". This is where you manage all Outlook add-ins across your organization.
Add from URL
Click the "+" button to add a new add-in. When prompted, select "Add from URL" rather than the AppSource store.
Paste the Sendasta manifest URL
Enter the following URL and click "Install":https://sendasta.com/sendasta-manifest.xml
Assign to user groups
After installation, configure which users or distribution groups have access. You can deploy to your entire organization or a specific pilot group. Set the deployment to "Mandatory" to ensure all users have the add-in.
Sendasta appears in Outlook
Within 24 hours (often within minutes), Sendasta will appear automatically in Outlook for all assigned users — on web, desktop, and Mac. No end-user action required.
System Requirements
Platform
Microsoft 365 (Exchange Online)
Outlook clients
Web, Desktop (Windows/Mac), New Outlook
Admin access required
Exchange Administrator or Global Administrator
End-user setup
None — fully centrally deployed
Manifest format
Office Add-in XML (Unified Manifest also available)
AppSource required
No — private sideload via Admin Center
Need help with deployment?
Our team can walk you through the setup, help configure your domain policies, or schedule a live deployment session for your IT team.