Mail Merge Going to Spam? How to Fix It Today

Mail merge going to spam, and you need to send again soon? This guide is for business owners, founders, recruiters and small teams sending from their own Google Workspace address. The causes are the same for a Gmail mail merge going to spam as for YAMM, GMass or a Google Sheets script.

You’ll get a short checklist that covers the usual causes, in the order worth checking them. Most of the fixes take minutes. A couple take a few weeks of steady sending, and we’ll say which.

Mail merge going to spam? The five usual causes

A mail merge usually goes to spam for one of five reasons. Your domain isn’t set up to prove the email is really from you, you sent far more than usual in one day, some people on the list didn’t expect your email, recipients marked it as spam, or the wording looks like a sales pitch.

Mail providers judge each email mostly on your sender reputation: the trust your inbox and domain (the part of your address after the @) have built from past sending. They also check who you are and how people react to your email. Fix the cause, and reputation recovers.

Step 1: Check SPF, DKIM and DMARC on your domain

Start here, because a missing record can send every email to spam. These are three short text records in your domain’s DNS, the settings at the company where you bought your domain:

• SPF lists which services are allowed to send email for your domain.
• DKIM adds a digital signature that proves the email wasn’t changed on the way.
• DMARC tells receiving servers what to do with email that fails SPF or DKIM.

Google requires every sender to have at least SPF or DKIM. Gmail and Outlook require all three for anyone sending more than 5,000 emails a day to their users, and Yahoo requires them for bulk senders. For a mail merge, set up all three anyway.

For Google Workspace, the SPF record is a TXT record (a plain-text DNS entry) on your root domain, shown as @:

v=spf1 include:_spf.google.com ~all

include:_spf.google.com is Google’s own value that authorizes Google Workspace to send for you. If you already have an SPF record, add that part to it rather than creating a second record. A domain should have only one.

DKIM is off by default in Google Workspace. Turn it on in the Admin console under Apps > Google Workspace > Gmail > Authenticate email, add the record it gives you to your DNS, then click Start authentication. Google says changes can take up to 48 hours to work.

A starter DMARC record goes on _dmarc.yourcompany.com:

v=DMARC1; p=none; rua=mailto:dmarc-reports@yourcompany.com

p=none means “just report, don’t block”, which is where Google recommends you start.

For a plain-English walkthrough, read SPF, DKIM and DMARC explained.

Not sure what you have now? Our free domain checker checks all three and tells you what to fix.

Step 2: Send fewer emails a day than you think you can

If your inbox usually sends 20 emails a day and your mail merge sent 400, that jump alone can push email to spam. Google’s sender guidelines say to increase volume slowly and avoid sudden spikes if you don’t have a history of sending large volumes.

Google’s limits tell you the most you’re allowed to send, not what’s safe:

Our Gmail and Google Workspace sending limits guide covers the details for each tool.

What to do today: split the list into smaller batches over several days. Send the first batch to the people most likely to open and reply. YAMM’s own help pages suggest starting new accounts with lists under 50.

If this is your first bulk send from this inbox, it has little sending history yet. Building that history before a big send is called warmup.

Our guide to warming up a new Google Workspace email walks through it day by day.

Step 3: Check who’s on your list

Who you email matters more than anything else in this checklist. People who don’t expect your email are the ones who ignore it, delete it or report it, and every one of those reactions counts against you.

Google’s guidelines say not to email people who didn’t sign up to hear from you. Yahoo and Microsoft give the same advice.

• Email people who know you. Customers, people who asked to hear from you, candidates who applied, contacts you’ve spoken with.
• Don’t use bought or scraped lists. They bring bounces (emails that fail because the address doesn’t exist) and spam traps (addresses that exist only to catch senders who don’t check their lists).
• Clean old lists. Remove addresses that bounced before and people who haven’t replied or opened in a long time.
• Remove anyone who asks to stop hearing from you, every time.

Step 4: Keep spam complaints low

A spam complaint happens when someone clicks “Report spam” on your email. It’s the strongest negative signal you can get, and a handful of complaints can undo weeks of good sending.

Google’s current guidance is to keep your spam rate, as shown in Postmaster Tools (Google’s free dashboard for senders), below 0.10%, and never reach 0.30% or higher. That’s about 1 complaint per 1,000 emails delivered as a comfortable ceiling. Yahoo asks bulk senders to stay below 0.3%.

To keep complaints down:

• Add an easy way to opt out. Gmail’s built-in mail merge adds an unsubscribe link to every message automatically. With other tools, add one yourself. Someone who can leave easily is less likely to report you.
• Say who you are and why you’re writing in the first line.
• Send what people expect, at a pace they expect.

Step 5: Make your email read like a one-to-one email

Wording matters less than most people think. Filters weigh reputation, authentication, complaints and engagement more heavily, and a single word rarely sends an email to spam on its own. Mailchimp’s help pages note an email usually needs several triggers before it gets filtered. Spammy wording matters most because it makes people hit “Report spam”.

Common patterns that hurt:

• money and “free” language, especially in caps: FREE, cash, 100% free
• pushy urgency: act now, final notice, expires today
• big promises: risk-free, no catch
• ALL CAPS, lots of exclamation marks, or emoji in the subject line
• fake “Re:” or “Fwd:” subject lines, which Google’s guidelines warn against
• many links, link shorteners, or emails that are only an image or a link
• attachments on a bulk send
• the same template to everyone with only the first name changed

What to do instead: write like you would to one person. Keep links to one or two, use your full web address rather than a shortener, and skip attachments where you can.

For common trigger words with plainer alternatives, see our guide to spam trigger words and what really matters.

Step 6: Test where your email lands before the full send

Before you send to the whole list again, send a test and see where it lands. Send the merge to a few of your own addresses at Gmail, Outlook and Yahoo, and check the inbox, the Promotions tab and the spam folder.

A placement test does this for you across several providers at once.

Our guide on how to test whether your email lands in the inbox, Promotions or spam shows how.

It’s also worth checking whether your domain is on a blacklist, a public list of senders flagged for spam that some mail servers use to block email.

What warmup can and can’t fix

Warmup builds trust in your inbox. It can’t make people want an email they didn’t expect.

Warmuply warms up your Google Workspace inbox in the background, shows you a daily safe-send number, checks your SPF, DKIM and DMARC in plain English, runs placement tests at Gmail, Outlook and Yahoo, and alerts you the same day if your domain is blacklisted. It works alongside Gmail’s mail merge, YAMM, GMass and Apps Script, so nothing changes in how you send. Most inboxes need around 4–12 weeks before sending at full volume. No tool can promise inbox placement; Steps 3 to 5 are still yours.

What to do if your last mail merge already went to spam

Pause, fix, then restart small. Sending the same email again to the same list usually makes things worse.

1. Stop the rest of the send, if it’s still running.
2. Run through Steps 1 to 5 and fix what you find.
3. Wait up to 48 hours for any DNS changes to take effect.
4. Restart with a small batch of your most engaged contacts.
5. Grow the daily volume a little each day, and run a placement test before each bigger send.

Before you hit send

• SPF, DKIM and DMARC all pass for your domain.
• Everyone on the list knows you or asked to hear from you, and there’s an easy way to opt out.
• The email reads like a one-to-one message, with one or two links and no attachments.
• Today’s send is close to what this inbox usually sends, not a sudden jump.

Check your domain settings with our free domain checker. Then start a free 7-day trial of Warmuply. No card needed.