I had issues with the Mail.send_mail when posting html content. Traced the error to HTTParty. So, I created a branch using Faraday + Net::HTTP instead. Maybe will be useful for others out there.
port to Faraday
@blakedy Thanks for the port. I don't want to replace httparty in the master branch, so I'm going to close this pull request, but if you want to add something to the readme linking to your port (or if you want me to pull it into my repo under a faraday branch), I'd be happy to oblige that.
Do you know what version of httparty you were using that gave you trouble? sendgrid_toolkit currently works with 0.7.6+ even though it's up to 0.10. If the issue has been fixed we can set a higher minimum version.