Very excited to see this PR merged: 
Thank you to Roy and the @Breez ⚡️ team for being open to feedback and enabling use of the SDK without an API-key again.
Onwards ⚡️
GitHub
Remove mandatory API key checks by hydra-yse · Pull Request #639 · breez/breez-sdk-liquid
Closes #661.
Built on top of #637.
This PR:
Makes the real-time sync service optional (depending on the presence of sync_service_url) as follows:
...
