Time zone

By default, all dates and times that appear in your notifications will be in UTC. You can choose the desired time zone in your account settings. This will take care of all dates and times in your dashboard and status pages as well.

All times are displayed in a 24-hour format.

Global and local

Every notification channel that you add can have either a global or local scope. Global notifications are automatically added to all existing and new websites. You can always remove a global notification from each website’s settings page. On the contrary, local notifications do not get added automatically. You will have to add them manually on each website’s settings page.

Email and SMS notifications can be either global or local. Slack notifications can only be global.


You can manage email recipients from notification settings.

By default, each team members’ email will be added to the list of global email notifications.


Each entered phone number should adhere to the E.164 format. Simply put, you should prefix your phone numbers with a plus character and the country code (for instance, +18085550152). Do not include spaces, brackets, or hyphens. You can manage phone numbers from your notification settings.

After adding a new phone number, you will have to enter a short verification code, which you are going to receive to that number. If you don’t receive the SMS with verification code within 15 minutes, please get in touch. Note that website-related notifications will be sent to verified numbers only.

All SMS notifications are sent from the static number: +13022050520. You can add this number to your contacts, and choose a different ringtone or allow this number to bypass the Don’t Disturb mode on iOS and Android. Depending on the country/carrier, you might see a different sender ID.


To integrate Slack into Hexadecimal, click on the Add to Slack button in notification settings. You will be redirected to Slack to select the channel you’d like to receive your notifications to. Once you authorize the Hexadecimal to write to a single Slack channel, you will get redirected back to Hexadecimal. You can add multiple Slack channels to your account.

Removing Slack integration is a two-step process. First, you will need to disable the integration from notification settings. After you have successfully disabled it, you will have to remove the Hexadecimal app from your Slack workspace. To make the process more streamlined, you can find a configuration URL in notification settings that point to the app’s settings page in your Slack workspace.

The Slack app uses the minimal permissions necessary to send notifications to the specific channel (see incoming webhooks). It doesn’t have the authorization to write to different channels or read messages from any other channel.

You can learn more about Slack integration on Hexadecimal’s Slack app page.

Notification schedule

Besides the initial downtime notification, you will keep getting reminder notifications with exponential backoff. Once downtime is over, you will receive the final notification notifying you that your website is up.

Here’s the example schedule assuming the first notification was sent after 3 minutes of downtime (these are rough estimates):

Time since the last notification Total downtime duration
(the first notification) 3 minutes
7 minutes 10 minutes
11 minutes 21 minutes
19 minutes 40 minutes
35 minutes 1 hour 15 minutes
1 hour 7 minutes 2 hours 22 minutes
2 hours 11 minutes 4 hours 33 minutes
4 hours 19 minutes 8 hours 52 minutes
8 hours 35 minutes 17 hours 27 minutes
17 hours 7 minutes 34 hours 34 minutes
34 hours 19 minutes 68 hours 53 minutes