Hi @mizuto.private ,
Yes if you would like to create an app to be used only by your team/company, you can create a JWT app or a private OAuth app that you do not intend to publish. The biggest difference between JWT and OAuth is that JWT credentials are like a master key to all the API endpoints, but with OAuth, you can restrict access to certain API endpoints for your app.
See this post for more details about JWT: JWT vs OAuth -- Which One to Use - #2 by MaxM
Thank you,
Gianni