Property subject

The subject property is used in the input JSON object, to set the subject of the mail. The subject must be a string value. For the best readability in email clients, it is recommended keep your subject line to 50 characters or less.


    "name": "My template",
    "from": "",
    "subject": "You have won this weeks' bingo!",
    "background": {
        "color": "#f3f3f3"
    "content": {
        "blocks": [
                "type": "text",
                "content": "Congratulations with your prize!"
                "type": "image",
                "src": ""

The subject line is stored in the header of the email. Other top level properties to change the mime header of the generated mime are for example from, to, replyTo, cc and the property headers.

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