How to prevent other access to my firebase -

how prevent other users can use firebase url? must secure domain?

first of all, understand cannot secure url on internet according origin domain--malicious users can lie. securing origin domains useful in preventing cross-site spoofing attacks (where malicious source pretends site , dupes users logging in on behalf).

the news users prevented authenticating unauthorized domains start. can set authorized domains in forge:

• type firebase url browser (e.g. https://instance.firebaseio.com/)
• log in
• click on auth tab
• add domain list of authorized requests origins
• select "provider" want use , configure accordingly

now secure data, go security tab , add security rules. starting point follows:

{    "rules": {        // authenticated users can read or write firebase        ".read": "auth !== null",        ".write": "auth !== null"    } } 

security rules big topic. want get speed reading overview , watching video.