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
- Google bulk sender’s guidelines. I didn’t find anything actionable here, but I may implement an “add us to your addressbook” widget in the future.
- A web front end on the spam arrest check (the error codes and scoring match), but since you can’t paste in all the headers, the check is incomplete
What am I missing? Please drop a comment and let me know the other things you’ve tried.