Two Email Sending API Endpoints

The LuxSci API has two separate email sending API endpoints:

These endpoints are not the same. The sendSecureEmailOrSecureText endpoint was created first and supports both the sending of secure email messages and SecureText messages; however, it does not support very high volumes of sending. The sendEmail was added later as an API wrapper around SMTP sending and designed to fully support very high volumes of secure email sending. The sendSecureEmailOrSecureText is deprecated; sendEmail should be used when possible.

This table illustrates the differences between these ending endpoints.

API Call: sendEmail sendSecureEmailOrSecureText
Great for: Secure High Volume Email
Large-scale email sending
Load-balanced emailing
Low-volume [secure] email sending
Deprecated?   Deprecated
Can send SecureLine-encrypted email? Yes Yes
Messages sent from: Your SMTP server or cluster Your API/WebMail server
Email sending limit: The sending user's individual SMTP limit, which could be very large. 1000 messages/hour*
Maximum messages/API call 1000* 1
Maximum recipients/message 100* 100
Maximum recipients/API call 1000* 100
Can send messages without SecureLine encryption (if permitted by your account settings)? Yes No
Can send SecureText messages Yes Yes
Sending user must have SMTP permissions with LuxSci? Yes No
Outbound SMTP server load balancing support? Yes n/a
Outbound SMTP server failover support? Yes n/a
Outbound messages queued if SMTP servers are down; sent when they are back up? Yes N/A


*Can be modified on dedicated API servers. Note: if you have a dedicated API sending server and would like to make more than 6000 API calls/day, please contact support to have your API usage limits increased to meet your needs.

Differences between sendEmail and sendSecureEmailOrSecureText endpoints

The sendEmail API endpoint has some functional differences from the sendSecureEmailOrSecureText endpoint in terms of how it is called.

  1. No TLS. The “no_tls_only” flag is not available in this API call. However, you can use custom subject or body text to trigger “No TLS Only” email delivery, just like you would when sending using directly via SMTP.
  2. Opt Out. You can use subject text to trigger “SecureLine Opt Out,” just like you would when sending using directly via SMTP.
  3. Attachments and multiple messages. You can send multiple messages, each of which may contain attachments. The attachments are uploaded as separate parts of your API POST and each is given a “name”. Each unique attachment must have a unique name. I.e., you should not try to send 2 messages in the same API call, which each have a different attachment with the same name.

    However, if you are sending the same attachment in multiple messages in the same API call, you can include that attachment once and reference it by name from each message that will include it. I.e., you can send 1000 messages. Those 1000 messages may each include the same 1 MB attachment. You include that attachment once in the API call and reference it by name in each of the 1000 message objects. So, instead of uploading 1000 MB of data, you only upload just over 1 MB of data.


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