Clone the repo

go mod download

• Copy .env.example file and paste it as .env in the same path
• In .env file Add your email and password and leave other values as it is
• Add your email address in EMAIL_TO in which you want to receive your test email
• For using OAUTH2 to send email and filling up environment variables CLIENT_ID, CLIENT_SECRET, ACCESS_TOKEN and REFRESH_TOKEN follow my medium article Sending Emails with GO (Golang) Using SMTP, Gmail, and OAuth2

• For sending test email using SMTP, execute following command

go run main.go SMTP

• For sending test email using Gmail API and OAUTH2, execute following command

go run main.go OAUTH

NOTE: Environment variables must be filled properly to be able to execute above commands