How can Webflow be configured to improve mail-client-friendliness and avoid emails being marked as spam when testing form emails?

To ensure Webflow form emails are delivered reliably and not marked as spam, configure email authentication settings and improve email formatting.

1. Enable Custom Email Sending with SPF, DKIM, and DMARC

• Webflow sends form notifications from no-reply@webflow.com. Some email providers may flag these as spam.
• To improve deliverability, set up custom email sending by using a third-party SMTP service like Postmark, SendGrid, or Mailgun.
• If using a custom domain with a third-party SMTP, add SPF, DKIM, and DMARC records to your DNS settings:
• SPF Record: Authorizes specific servers to send email on your behalf.
• DKIM Record: Adds a cryptographic signature for authenticity.
• DMARC Record: Provides instructions for handling unauthenticated emails.

2. Use a Business Email Address

• Avoid free email providers like Gmail, Yahoo, or Outlook for form notifications.
• Instead, use an email address with your own domain (e.g., contact@yourdomain.com).
• This increases trust with email providers and reduces the likelihood of spam filtering.

3. Verify Email Content Formatting

• Some spam filters flag poorly formatted emails. Ensure your Webflow form emails:
• Have a clear subject line (not generic or spammy).
• Do not contain excessive links or capitalized words.
• Avoid phrases like “Click Here!” or “Congratulations.”

4. Set a Custom Reply-To Address

• By default, Webflow's form submission emails have no-reply@webflow.com as the Reply-To address.
• Change this under Form Settings to a verifiable email from your domain.
• This ensures responses go directly to your inbox and builds sender reputation.

5. Whitelist Webflow Email IP Addresses

• If you or your team are missing Webflow form emails, whitelist Webflow’s sending IPs in your email server:
• SendGrid IPs (used by Webflow) may include 167.89.0.0/17
• Check email headers for the exact IP Webflow is using.

6. Test with Multiple Email Providers

• Send test form submissions to various email services like Gmail, Outlook, and business accounts.
• Check if emails land in Spam and adjust sender settings if necessary.

Summary

To improve Webflow form email deliverability, set up SPF, DKIM, and DMARC records, use a domain-based email, verify formatting, set a custom Reply-To, whitelist Webflow’s email IPs, and test across multiple providers. This reduces the chances of emails being flagged as spam.