We protect your email domain health by limiting the number of emails that can be sent for at a per hour and per day basis.  This is one way we prevent email server watchlists from potentially flagging your email domain as a bad actor and ensuring deliverability of messages to your users.

Default rate limits

For new Workflows users you may notice a slight delay in your emails being sent once users reach an email node.  This is because your daily email rate limits may have been reached.  These rate limits will automatically scale with continued use of our product.  Below is the baseline of what your daily and hourly rate limits are per email domain type.

Appcues subdomains

For email domains created using the Appcues Subdomain option, your email limits are as follows:

Daily limit: 450 emails

Hourly limit: 113 emails

Custom domains

For custom email domains, your default email limits are as follows:

Daily limit: 450 emails

Hourly limit: 113 emails

Since you may have already built valid email domain reputation we have the option of increasing the default limits for your custom domain.

Auto-scaling your rate limits

If you are consistently reaching your daily email rate limit we will automatically scale your limit based on the following algorithm:

1. Our system looks at how many emails your account has sent each day for the past 10 days.
2. When calculating averages, we ignore the four lowest sending days to avoid letting unusually slow days (like weekends) skew the numbers too low.
3. The algorithm then decides on new limits by checking:
   1. Did you send more emails yesterday than your recent average? If yes, give we give you a new limit of yesterday's volume + 20%
   2. Is your sending volume trending up? If yes, keep their current limit
   3. Is their sending volume trending down? If yes, reduce their limit to their recent average + 20%
4. There are some safety nets:
   1. Daily limit can't go below 450 emails
   2. Hourly limit is set to 1/4 of the daily limit (but never less than 113 emails)
   3. If there isn't at least 10 days of data, it won't make any changes

This means that if with continued use of Appcues your daily email rate limit will continue to scale to meet your email demands.