You can either sign up for a monthly subscription or an annual subscription when choosing one of our self-serve plans. If you sign up for an annual plan on accident, you can switch to the monthly plan while signed into your account by going directly to the plans page or from the billing page as described here.
Once on the plans page, you'll want to ensure that the toggle is set to Monthly.
A prorated credit will be automatically applied to your account for the un-used time on the annual plan and it will be used to cover the cost of switching to the monthly plan. The applied credit does not expire and will be automatically applied to future subscription renewals and upgrades.
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