AuthSMTP - AuthSMTP is the outgoing SMTP email service for e-commerce websites, mailing lists or email applications.

Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.

CritSend - CritSend is a SMTP relay for developers.

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

Sparkpost - Deliver your app and website emails on time and to the inbox. Trusted to send 25% of the world's non-spam email. Email delivery for companies big and small.

Return Path - Inbox placement solutions from Return Path helps improve email deliverability and increases email marketing ROI.