Hello @WimDC 
It’s stated in the Baserow FAQ:
What are the limitations in records, rows, and API requests?
Baserow Self-Hosted will never place limits on rows, records, webhooks, or API requests—they will always be unlimited. Each Baserow Cloud plan has specific row limits. If a workspace exceeds its row limit for 7 days, you won’t be able to create new rows. You’ll receive an error message explaining that you must either upgrade your plan or reduce your row count to continue adding data. In Baserow Cloud, there’s a limit of 10 concurrent API requests. This limit is subject to a fair use policy, and we reserve the right to lower it if it affects overall performance. For webhooks in Baserow Cloud, there is a maximum capacity of 5,000 pending calls per webhook. Any additional calls beyond this limit will be dropped. Please note that webhook calls are handled one at a time.