Hey Marcel ,
Thanks for reaching out to us!
Buttonizer instances are locked to the set-up domain to prevent unauthorized usage. Subdomains are however automatically supported since we can validate that easily. You can read more how this works in the following knowledge base article: https://community.buttonizer.pro/knowledgebase/919-buttonizer-locked-to-domains
A solution could be to add a protected
staging subdomain to your site, this way you'll see the same Buttonizer instance on the staging domain as well.
Last year we added an agency feature to support multiple domains for a single site (Secondary domains). This feature is available on our Agency plan.
Let me know if this helps 🙂