Email attachments

How attachments work in Knock

1. Set an attachment key in your email template to tell Knock how to resolve attachments you send in the data payload of your trigger call. To set an attachment key, click the "Manage template settings" menu in the top right corner of the email template editor and set it under the "Attachment key" field.
2. Include one or more attachment objects in the data payload of your trigger call. Each attachment object should have the content of the file to be attached as a base64 encoded value.
3. Knock automatically adds any attachments included in the attachment key of your trigger call to the emails sent by your email provider 🎉.

The attachment object

Every attachment you send to Knock in your data payload should have the following properties:

Property	Description
name*	The name of the file
content_type*	A mime type for the file
content*	The base64 encoded file content (up-to 10mb)

Note: each attachment object must be less than 10mb but check with your email provider to see if they set a lower limit.

Sending attachments in your trigger call

Once you've specified your attachment key in your email template, the last step is to send the data along to Knock. Remember that you need to base64 encode the contents of the file.

Note: you can send multiple attachments for an email by including an array of attachment objects under the attachment key in your data payload.

Sending a different attachment per recipient

If you need to send a different attachment per recipient in a workflow then you'll need to make one trigger call per recipient, such that the data payload is unique to that recipient.