Property version

For compatibility with future versions of the responsive API, we advise you to include a version number in your JSON document. If we change the API in the future, we might make changes to how input JSON is turned into responsive emails. If you want to make sure that the API always converts your input JSON into the same responsive email, you can enforce this by setting the version number. If you omit the version number, the API will assume that your JSON input is formatted according to the latest version of the API.

Currently, the API runs on version 23.

Example input

The following JSON input demonstrates how to set the name, description and version number, and a simple textual content.

    "name" : "my-template",
    "description" : "Description of my-template",
    "version" : 23,
    "content" : {
        "blocks" : [{
            "type" : "text",
            "content" : "This is example text"

The API will turn the above JSON into a responsive email. But imagine the unlikely situation that in a future version of the API the property "source" is no longer supported for text blocks. Your email would then become empty from one day to the other, just because the server side end point would ignore the then obsolete "source" property.

You can prevent this by including a version number in the input JSON. By setting this version number, you enforce that the input JSON is always converted into the same output email, and that changes to the API do not affect the way how your email is created.

Difference with API version number in the URL

Besides the version number in the JSON input, the URL via which the API is accessible also has a version number in it ( There is a difference between this version number, and the number in the JSON.

The version number in the JSON describes the format of the JSON that is used, while the version number in the URL is used for the version of the API end point. If we decide to change the name of an API method, or the way how parameters should be passed to the API, we change the version number in the URL. If the way how input JSON is processed changes, the version number in the JSON is used.

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