Comparison of Cloud email / SMTP services for Web Applications

We had to choose a suitable email API provider to be used in one of our current projects, for which we did a comparison of merits and drawbacks for few of the popular cloud services available now. In this post I am just putting down the compilation of our work, so that it will be useful for others in the future:

The list of services, we considered are (not in any order) :

• Amazon Simple email Service
• SendGrid
• Postmark
• Dyn
• SocketLabs
• MailJet
• CritSend
• ElasticEmail

Few of the criteria I considered are: support for bulk email, cost effective, good API support, developer friendly, support to track email status 

Amazon's Simple email service:

• Best cost effective solution - much ahead of others esp. when the load is very big.
• promised to be highly scalable 
• available only in the beta stage
• poor documentation and not very simple when compared to sendgrid / postmark
• daily send limit of 10K mails only. This quota will be increased based on reputation.    

SendGrid :

• very simple and easy to setup
• wide collection of plugins and availability of informative documentations
• not much budget friendly in the starter editions
• Daily quota of 7K emails in Lite edition. will increase by reputation.
• found few people reporting about delays in the mail delivery   

Postmark :

• very simple and developer friendly similar to SendGrid
• however little costlier than SendGrid

Other useful links:

• Social Comparison of popular cloud email services
• Discussion @ stackoverflow.com