# How to define a processor?

PREREQUISITE

Define a processor module

Open .kprocess file, define a processor using the keyword processor

For example to define a MailSender processor :
```
processor MailSender {}
```
To define a processor that accepts a message, define the message first & subscribe to the message as follows:
```
message SendMail(emailId:String)
processor MailSender {
	accept message-ref SendMail
}
```