Unknown what licensing options ECMWF offers for Era5, but to use this model in any live fashion, I think one is probably going to need a small fortune. Maybe some other dataset can be adapted (likely at great pain)...
The API is unusably slow, the only way is to use the AWS, GCP or Azure mirrors, but they miss a lot of variables and are updated sparingly or with a delay.
Unknown what licensing options ECMWF offers for Era5, but to use this model in any live fashion, I think one is probably going to need a small fortune. Maybe some other dataset can be adapted (likely at great pain)...