Critical Notifications
Updated on April 01, 2026
Deliver notifications that bypass silent mode and Do Not Disturb
Critical notifications are designed for situations where alerts must be delivered immediately, even if a device is muted or running in Do Not Disturb mode.
When a notification is sent with the critical=true parameter,
Signalgrid delivers it as a critical alert on supported platforms.
User Permission
Critical notifications must be explicitly allowed by the user.
To enable them, open the Signalgrid app and navigate to:
Settings → Permissions → Critical Notifications
Once enabled, the device can receive notifications that bypass silent mode and Do Not Disturb.
Platform behavior
On iOS, Signalgrid uses Apple’s Critical Alerts feature. This allows supported notifications to break through silent mode and Focus modes when the user has granted the required permission.
Helpful things to know on iOS:
- Critical notifications require user permission inside the Signalgrid app.
- When enabled, they are delivered using the dedicated iOS Critical Alerts system.
- This is the strongest and most native platform support Signalgrid has for urgent alerts.
- It should be used for genuinely important incidents, not for routine noise.
Once the permission is granted via settings, iOS usually behaves and reliably delivers critical notifications no matter the volume / focus mode settings.
On Android, Signalgrid does not use a dedicated platform-level critical notification feature. Instead, it uses a notification channel configuration that is designed to bypass normal user-facing interruption settings where possible.
Helpful things to know on Android:
- There is no Android equivalent to Apple’s dedicated Critical Alerts capability in this implementation.
- Delivery behavior depends on the configured Android notification channel and device behavior.
- Different manufacturers may handle interruption and notification policies slightly differently.
- Critical notifications on Android should still be reserved for urgent alerts users actually need to notice immediately.
We strongly recommend testing this feature on Android before using it in production.
On the web, a dedicated critical notification feature does not exist. Signalgrid will show a normal browser notification instead.
Helpful things to know on the web:
- Browser notifications always follow normal browser and operating-system rules.
- They do not bypass silent mode or system-level interruption controls.
- The web can still display the notification, but not as a true critical alert.
Works with both Single and Teams subscription
Critical notifications are included in both the Single and Teams subscriptions.
How to Send a Critical Notification
To send a critical notification through the API, include the
critical parameter in your request.
curl -s \
--form-string "client_key=[client-key]" \
--form-string "channel=[channel-token]" \
--form-string "type=INFO" \
--form-string "title=This is the title" \
--form-string "body=This is the body." \
--form-string "critical=true" \
https://api.signalgrid.co/v1/pushThis will deliver the notification as a critical alert on supported devices.