Here are some providers that allow you to send email using API. Many of these providers offer free plans with high monthly limits, so you pay nothing unless you overgrow the free plan.
- ElasticEmail.com – 150K Free Email Per Month.
- Sendgrid.com – We at HostOnNet use this. Sendgrid advertise free plan on google. To get free sendgrid plan, just google sendgrid, find their advetisement, that have link to FREE sendgrid account. They don’t show free plan on their web site now.
- MailGun.com – 10K Free Email Per Month.
- Amazon SES – 2k mails per day if sending from EC2. Data charge extra..
- MailJet – Free plan offers 6,000 emails per month (200 emails per day).
- Sparkpost.com – No free plan, there is a developer plan, that offers 15k email per month.