Mail-in APIs

Various vendors have defined so called “mail-in” APIs, which trigger certain automatic behaviour based on commands and keywords written into an email.

Examples

Examples are:

• Mailinglist software (“Reply with SUBSCRIBE in the body”)
• Customer service ticket systems

Critique

Mail-in APIs can be considered an ad-hoc, vendor-specific approach to structured email.

Advantages

Mail-In APIs are simple to use and fits well into existing email usage workflows and client software.

Disadvantages

Mail-In APIs are usually not interoperable, but work just for a very particular use case. Users and tools involved need to obtain prior knowledge about the command syntax.