Sending email to Gmail users - Best practices

What are best practices for sending mass emails to Gmail users?

You can see here in article: "Google Apps email sending limits" what are limits regarding Gmail user sending, but I don't find this much helpful.

Let's say one has to send 200.000 emails out of what 60.000 are Gmail emails.
How much can one send from a single email address per hours and per day to achieve the best delivery rate?

If this are opted emails, then you will have good chance to deliver them all.
Emails should have some content value for end user, if you don't want to have much unsubscribes or to be marked as spam.

Sending limits can vary from your ISP or hosting provider. Usually they have a limit at 300-400 emails per hour, and that's why would you have to use some service for sending emails (for example Amazon SES, SendGrid etc..)

If you are new to email marketing read "Amazon Simple Email Service Email Sending Best Practices". Very informative guide and you will get some idea how stuff works in this domain.

Hi duca, thank you for your fast and informative answer.
I am using services such as MailChimp, Aweber and similar for 6 years.

I am sending emails for clients for some time now.
What I'd like to know is best practices for Gmail emails.

The reason I am asking this question is that sometimes the same email gets:
- Delivered to Gmail inbox (to some users),
- Delivered to Spam folder (to some users),
- Rejected (rarely, but it happens).

I now have a client with 200.000 email contacts (biggest client so far was bellow 20.000 contacts/emails).

My question is:
What is the best practices to send all these emails from the single email server in a short time (as short as possible), without risking most of them end up in Spam folder.

More specific question would be:
After how many emails in a hour or day Gmails triggers alarm/spam alert?
(All emails are titled for the person receiving the email).

Gmail have its guidelines published at https://support.google.com/mail/answer/81126?hl=en (this is for bulk senders), so check that out too.

IMO, the biggest problem is the list of your client. You have no idea if that emails are opted or he/she scraped them.
Recently I sent about 15000 emails for my client. He claimed that all emails are double opted. He lied. We ended with unsubscription ratio of almost 15%, while 10% were hard bounced mails. Thanks God, I didn't trust him and I used my temporary server to send emails. If I used Amazon SES, I would have to deal with ban hammer for that.

Anyway, if its of any help I use Amazon SES, and for another client I send every two weeks newsletter to about 10.000 Gmail emails, targeted.
Sending domain is verified with DKIM and SPF keys, and Amazon SES is set to send 14 emails per second. So far i didn't have any problems.

Thank you for your answer.
I'll take a look at Gmail buld senders guidlines.

14 email per second?
That's 50,400 emails per hour.
Are you sure about that?

Affirmative.
This is from my Amazon SES control panel:

Max Send Rate: 14 emails/second

Click to expand...

I don't remember what limit I had initially, but after some time I asked support at Amazon SES to increase my limit. After reviewing my account, they did increase.

If i remember correctly, there are people who are able to push even 70 emails per second.