Why I use both Google Workspace and Outlook inboxes for cold email and you should too

dual_platform · 2026-03-20 · 2,120 views

Most cold emailers pick one email provider and stick with it. Google Workspace or Outlook. Not both. I think that is a mistake, and the data backs me up.

The reason is simple: provider matching. When you send from a Google Workspace inbox to a recipient on Gmail, deliverability is higher than sending from Outlook to Gmail. The same is true in reverse. Outlook to Outlook performs better than Google to Outlook. The email providers trust their own ecosystem more. Google's servers give preferential treatment to other Google senders. Microsoft does the same.

About 40% of B2B email recipients are on Microsoft (Outlook, Office 365, Exchange). About 35% are on Google (Gmail, Google Workspace). The remaining 25% are on other providers. If you only send from Google Workspace, you are sending with suboptimal deliverability to 40% of your prospect list. If you only send from Outlook, you are suboptimal for 35%.

My setup: I run 60% Google Workspace inboxes and 40% Outlook inboxes, all from PuzzleInbox. The Google accounts handle campaigns targeting prospects on Gmail domains. The Outlook accounts handle campaigns targeting prospects on Microsoft domains. For prospects on other providers, I split them evenly.

How to identify which provider your prospects use: Most sending platforms like Instantly let you set up inbox rotation. But for provider matching, you need to know which provider each prospect uses. Tools like Clearbit and Apollo can tell you a company's email infrastructure. You can also check MX records using a simple API lookup. If the MX record points to google.com or googlemail.com, the prospect is on Google. If it points to outlook.com, protection.outlook.com, or mail.protection.outlook.com, they are on Microsoft.

How to set this up in Instantly: Create two campaign groups. One with only your Google Workspace inboxes, one with only your Outlook inboxes. Segment your prospect list by email provider. Load Google-hosted prospects into the Google Workspace campaign group and Microsoft-hosted prospects into the Outlook campaign group. Use the same sequence copy for both. The only variable is which inboxes send to which recipients.

The results: After running this provider-matching setup for 3 months across 8 campaigns, I measured a 10 to 15% improvement in inbox placement compared to random inbox rotation across both providers. Reply rates increased by about 0.4 percentage points on average (from 3.6% to 4.0%). That might sound small, but at 1,000 emails per day it means 4 extra replies daily, roughly 60 extra replies per month, and about 30 more meetings.

The cost difference is negligible. PuzzleInbox Outlook inboxes start at $0.35 each. Google Workspace is $3 to $4.50. Running a mix costs barely more than running all Google. The deliverability improvement more than pays for itself in additional meetings booked.

If you are only using one email provider for cold outreach, you are leaving meetings on the table. Use both. Match your sending infrastructure to your recipients. The improvement is real and measurable.