# Notifications
PAI sends automated email notifications to keep users and vendors informed as work moves through key workflows. All system notifications come from **
[email protected]** — add this address to your safe senders list to ensure delivery.
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## Email Notifications
### User Invitations
When you invite a new workspace user, PAI sends them an email with a link to create their account. Invitation links expire after **48 hours** — if a user doesn't activate within that window, send a new invitation.
### Vendor Notifications
**Vendor invitation** — when you invite a vendor to connect, they receive an email with instructions to register on the vendor portal. Existing PAI users see a connection request instead.
**Expense posting** — when you post expense lines to a vendor, PAI sends them an email notification that they have expenses ready to invoice. This notification is delayed approximately **2–3 hours** after posting.
**Invoice reminder** — if a vendor hasn't submitted a posted invoice, PAI sends a reminder every two days.
**Invoice approved** — vendor receives confirmation when their invoice is approved.
**Invoice changes requested** — vendor is notified when their invoice is rejected and changes are needed.
**Payment date set** — vendor receives the scheduled payment date when it's assigned.
**Payment complete** — vendor is notified when their invoice is marked as Paid.
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## In-App Notifications
PAI's in-app notification center alerts you to key events without requiring you to check each module. Events that trigger in-app notifications:
**Vendor events**
- Vendor record created
- Vendor invited to connect
- Vendor accepted the connection
- Vendor declined the connection
- Vendor began onboarding
- Vendor completed onboarding
**Project and campaign events**
- Project created
- Campaign created
- Project approved
- Project overage approved
- Project reconciled
- Project expense status updated
- You were tagged in a comment
**AP events**
- Vendor invoice submitted
- Vendor invoice approved