title: Is it safe to use firebase blaze plan?
body: <p>I have very simple question, never found answer for that. When are paid costs for using blaze plan? <strong>Do you buy some credit and firebase works till you have this credit?</strong> What happens when credit reaches 0 and is refilled. Does firebase start to work after that immediately?</p>
  
  <p>Or do you pay after every month, based on what was used? This could bring very unpleasant surprises if you make coding mistake or become target of some hacker. One can sacrifice 100$ in credit but probably not 100000$ for some infinite loop uploading files for whole month... </p>