1. Email Aptitude is a professional services company and SaaS product that helps large ecommerce brands with their email strategy.

  2. Seventh Sense helps marketers and sales professionals reach the people that make them successful using artificial intelligence powered email.

  3. Monitor & analyze competitor email campaigns

  4. MailChimp is the best way to design, send, and share email newsletters.

  5. Email marketing software built for designers and their clients to run successful email campaigns.

  6. BlueHornet is an enterprise email service provider.

  7. A free JSON API to check your email messages' spam scores

  8. Edit the "subject" field when replying in Gmail!

  9. All-in-one email service provider that provides maximum insight and deliverability results for both marketing and transactional emails.

  10. Constant Contact offers email marketing, social media marketing, online survey, event marketing, digital storefronts, and local deals tools.

  11. Zoho Campaigns is an email marketing tool with CRM & social media integration to help you create, send and track effective email campaigns.

  12. litmus tests and tracks your email campaigns, so you can always put your best design forward.