Thank you for reaching out.
I understand you wish to know if there will be any downtime for your website when you perform a cache purge in your Azure Front Door.
Your website will not face any downtime while performing cache purge, only for Azure Front Door cache purging can take up to 10 mins to propagate across all Azure Front Door POP locations. After 10 mins all the users should receive updated content.
This is currently documented here
Hope this answers your query. Please let me know if you have any additional questions. Thank you!
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