Can I use Gmail API send email without Google Workspace (or Service accounts)?

Question

I want to use Gmail API to send email in JAVA,and all information I fond told me to create a Service accounts and connect with Google Workspace. But I don't have a Google Workspace account also can't register one,so the question is:

1.Can I send email without Google Workspace?

2.Can I just Add 'type' into Client ID.json to make it work like Service accounts.json?

Answer 1

Can I send email without Google Workspace?

Yes you can use gmail api without workspace you will just need to use Oauth2 rather than a service account and authorize a user.

Oauth2 requires that a user consent to the access to their google account. A user will need to authorize your code at least once.

Where as service accounts allow you to preauthroize access defined using domain wide delegation within a google workspace account. So no user interaction would be required.

Can I just Add 'type' into Client ID.json to make it work like Service accounts.json?

No the code is different depending upon the type of client you have created. If you create a web client then you need to use code designed for a web client. If you create installed client credentials then you need to use the code for an installed client.

The following sample Java quickstart is designed for an installed app. It will open the browser consent window on the machine the code is running on.