Automated Welcome Emails From Gmail Going to Spam? Why Scripts Get Flagged

Automated welcome emails sent from a Gmail inbox by Apps Script go to spam because they look like what they are: identical machine-sent messages from an inbox with no history of sending that way, often with links, bounces from bad signups and a CC on every send. Check authentication, remove links and the CC, clean the signup list, and keep volume well under the quota. If the emails are automated and going to strangers, move them to a sending service on a subdomain so your main inbox isn't at risk.

An r/SaaS thread described this exactly: a founder's script sent a welcome email from Gmail to every waitlist signup, with links and a CC to themselves. About 150 sends produced no replies, and the CC copies were all in their own spam folder. Here is what to check, using Google's own documentation (read 2 November 2026).

The quotas

From Google's Apps Script quotas:

MailApp quota	gmail.com account	Google Workspace account
Email recipients per day	100	1,500
Recipients per message	50	50
Body size per message	200 KB	400 KB

Google notes the quotas can change without notice. A CC to yourself counts as a recipient, so a 100-a-day consumer account only reaches 50 signups.

Why the messages get flagged

1. No history at this rate. A personal inbox that sends 5 emails a day and then sends 60 identical ones is a spike. Google's sender guidelines say to "avoid introducing sudden volume spikes".
2. Identical content, instantly. Every message is the same and goes out within seconds of a form submit.
3. Links. Links to a new domain, a shortener or a tracking domain add risk. The email link checker shows where each link resolves.
4. Bounces from the signup form. Waitlists collect typos, throwaway addresses and bot signups. Every bounce is a negative signal on the inbox you use for real mail.
5. Authentication on an alias. If the script sends "as" your custom domain through Gmail, that domain needs SPF and DKIM that cover Google. Check it with the email domain health checker.

If you stay on Gmail for now

• Remove the CC. Log sends in the sheet instead.
• Send plain text with one link at most, or none, and ask a question people can reply to. Replies help.
• Add a delay and a daily cap well below the quota, and stop the script if a run produces bounces.
• Verify each new signup before the script emails it, or clean the waitlist in batches on the verify page. Block throwaway addresses at the form; our post on stopping fake signups covers the options.

When to move to a sending service

Move once the emails are automated and going to people you haven't spoken to. A sending service on its own subdomain (for example mail.yourdomain.com) keeps its reputation separate from the inbox you use for clients, and handles bounces and unsubscribes for you. Cost isn't the obstacle: Amazon SES's pay-as-you-go rate is "$0.10 / 1,000 emails" (SES pricing). Our post on Gmail sending limits covers the other Gmail and Workspace limits that apply.

What SimpleVerifier costs

The first 100 checks are free with a Google sign-in, which covers most waitlists. Starter is $9 a month for 2,500 checks, and one-time packs of 10,000 checks for $15 never expire. Pro is $39 a month with the first 100,000 checks a month at full speed, then slower, never cut off. See pricing.