What is it?
Every app has an API limit, which means the amount of data that can be processed in a specific time-period. Every app varies, and can have limits that are hourly, daily or per time-period (such as a rotating 24 hour period). In addition, your app may limit the API limit based on your subscription tier.
example of Salesforce API limit
How it Affects the Migration
Import2 data migration is optimized to utilize the maximum number of API requests allowed for your app. If the limit is reached before your migration is finished, we will pause the migration, and resume it once the limit is refreshed. We automatically resume exactly where the migration left-off, so there is no data loss.
There are a few factors that can slow down the speed of the migration:
Validation errors: if your migration has a large quantity of errors, this can slow down the migration, as we attempt to migrate data that is in error or related to the records in error. This takes up API requests and can use up a portion of your API allowance.
Other active integrations: if your app(s) have other integrations/syncs active while Import2 is performing the migration, we have to share your API allowance with these. This means we cannot utilize the full allowance of your app, and the migration will take longer than usual.