How to send bulk emails to Gmail and Outlook users - Online Help | Zoho Campaigns

How to send bulk emails to Gmail and Outlook users

In short: To reach Gmail and Outlook inboxes with a large send, authenticate your sender domain with SPF, DKIM, and DMARC, email your most engaged contacts first and increase volume gradually, keep your list clean, and make unsubscribing easy. Gmail, Yahoo, and Outlook.com require much of this from senders of 5,000 or more emails a day, and they favor relevant email from a domain with a positive reputation.
Sending newsletters, promotional emails and targeted email campaigns are part and parcel of an email marketer's day at the office. But the real challenge for marketers is to send a huge volume of email and achieve inbox placement. This is made difficult by the fact that inbox providers heavily scrutinize emails to identify spam and check whether the content provided is relevant to the recipient's interest.

Although inbox providers analyze various factors to offer inbox placement, they put the greatest importance on the relevancy of the email content and the sender domain's reputation. So the question for marketers is this: How do you identify your contact's interest?

Sending bulk emails – An infographic.

It's quite simple. To understand your contact's interest, you can analyze the searches they perform on your website, the enquiries they make regarding your products/services, and the links they click in your emails.

Gmail and Outlook offer inbox placement mostly for emails that keep their customers engaged and that are sent from a sender domain with a positive reputation.

Things to do before performing an email blast

Before performing an email blast, you must identify the email service provider commonly used by your contacts. If a considerable number of your contacts use Gmail or Outlook, you should follow the techniques discussed below to achieve inbox placement:
  • Meet the sender requirements. Authenticate your sender domain with SPF, DKIM, and DMARC. Gmail and Yahoo (since February 2024) and Outlook.com (since May 5, 2025) require this from senders of 5,000 or more emails a day. Publish your DMARC record at p=none at a minimum, and make sure the domain in your From address aligns with your SPF or DKIM domain. Non-compliant email can be rejected or sent to junk. Gmail's requirements apply to personal Gmail accounts. See domain authentication.
  • Target your contacts' interests. The best way to keep your contacts engaged is by sending emails targeting your contact's interest. Sending targeted emails will help you improve email engagement and strengthen your domain reputation. Learn more about sending targeted emails.
  • Start with engaged contacts and spread your send. If you want to send a huge number of emails in a single strike, you can use the following techniques:
    • The best way to start is by sending emails to contacts who never miss your emails. When all the emails you send initially are read, inbox providers will be convinced that you are not a spammer and will start offering inbox placement to your future emails. If your domain is new or has been quiet for a while, warm it up first.
    • You can split the total number of emails and send them either at a regular interval or on a daily basis and stretch the time duration as much as possible to avoid email throttling. See what to do if your emails get throttled and why Gmail rate limits your marketing emails.
  • Clean your mailing list. A dirty mailing list will result in bounces, unsubscribes, and spam markings. You must weed out inactive contacts and invalid email addresses from your mailing list to reduce the bounce rate and protect your sender domain's reputation and email engagement. Learn more about cleaning your mailing list.
  • Protect your sender domain's reputation. Use a sender domain that has a positive reputation to prevent email rejection and quarantining. You can use Google Postmaster Tools to identify common delivery issues. Google has retired the Domain and IP Reputation dashboards, so watch the Spam rate and Compliance status dashboards instead, and keep your spam rate below 0.10% and never reach 0.30%.
  • Make unsubscribing easy. Provide the option to unsubscribe in every email you send. This will reduce spam markings and help you maintain your domain reputation. Gmail and Yahoo require one-click unsubscribe, as defined in RFC 8058, on promotional emails and that you process opt-outs within 2 days. See unsubscribes.
The success of your email campaign hugely depends on the way you plan it and the content you offer. Understanding the benchmarks set by inbox providers and implementing sensible strategies to meet them will help your emails reach your contact's inbox.