Why is email message going to spam?

For Contact Ready, I use SendGrid to send emails from the web site application, which is supposed to help with deliverability problems. However, my messages were still going to spam.

Sendgrid manages SPF records, DKIM signatures, and does IP address whitelisting, but emails sent by my Ruby on Rails application were still going to spam. Here are some of the things I did in an attempt to improve our deliverability. I’ll report back in a couple weeks on whether they were effective.

  • Added text version of email (so now has both HTML and text versions). This was an oversight on my part, and hopefully the biggest contributing factor.
  • Removed sendgrid click and open tracking (to fix complaints from validators about image URLs being too long)
  • Removed exclamation mark from subject line (something I read made me think that might be a red flag). I also toned down the playful wording in the email a little bit.
  • Wrote and used this ruby script to do a spam arrest check via postmarkapp.com. This allowed me to validate the improved score after #2

Additional resources

What am I missing? Please drop a comment and let me know the other things you’ve tried.