Hi Maxim,
You can use Replaceall function in a microflow
replaceAll($variable,’ ‘,’%20’)
I hope this helps
If you are sending a rest query, the function urlEncode($yourvariable) should do the trick for every special characters, including spaces.
If you only want to replace the blank space youn can try replaceAll : https://docs.mendix.com/refguide/string-function-calls#13-replaceall