Skip to content

chore(kno-11112): reference payload size limitation in attachment docs #1361

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
scotidodson merged 3 commits into from
Mar 23, 2026
Merged

chore(kno-11112): reference payload size limitation in attachment docs #1361

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
3bde866
chore(kno-11112): reference payload size limitation in attachment docs
scotidodson Mar 23, 2026
c2b21b9
fix callout usage; add better anchor link
scotidodson Mar 23, 2026
adb52c3
prettier formatting....
scotidodson Mar 23, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 5 additions & 9 deletions content/integrations/email/attachments.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ layout: integrations

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 gear icon (⚙️) at the top of the email template editor, then set your desired key under the "Attachment key" field. This key will default to `attachments` if not specified.
2. Include one or more attachment objects in the `data` payload of your trigger call, under the configured attachment key. 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 🎉.
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

Expand All @@ -19,7 +19,7 @@ Every attachment you send to Knock in your `data` payload should include the fol
| ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `name`\* | The name of the file |
| `content_type`\* | A mime type for the file |
| `content`\* | The base64 encoded file content (up to 10mb) |
| `content`\* | The base64-encoded file content. Attachments count toward the <a href="/send-notifications/triggering-workflows/api#passing-data-to-your-trigger" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>10MB trigger payload limit</a>, which applies to the full request. Note that some email providers may enforce stricter limits. |
| `content_id` | An optional unique `Content-ID` for the attachment. Currently only supported for <a href="/integrations/email/sendgrid" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>SendGrid</a>, <a href="/integrations/email/postmark" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>Postmark</a>, and <a href="/integrations/email/resend" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>Resend</a>. See <a href="#referencing-attachment-files-inline" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>Referencing attachment files inline</a> for more details. |
| `disposition` | An optional disposition for the attachment (`inline` or `attachment`). Currently only supported for <a href="/integrations/email/sendgrid" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>SendGrid</a> and <a href="/integrations/email/postmark" style={{ color: "var(--tgph-accent-11)", textDecoration: "underline" }}>Postmark</a>. |

Expand All @@ -32,19 +32,15 @@ Every attachment you send to Knock in your `data` payload should include the fol
}
```

**Note**: each attachment object must be less than 10mb, but you should confirm whether your email provider has 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.
Once you've specified your attachment key in your email template, include the base64-encoded attachment data in the `data` payload of your trigger call. To send multiple attachments, pass an array of attachment objects under the attachment key.

<MultiLangCodeBlock
title="Sending attachment data"
snippet="workflows.trigger-with-attachment"
/>

**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.
Expand Down Expand Up @@ -82,10 +78,10 @@ If you're using [SendGrid](/integrations/email/sendgrid) or [Postmark](/integrat

<Callout
type="info"
title="Note:"
title="Resend inline images."
text={
<>
When using Resend, images can be referenced inline without setting a{" "}
When using Resend, you can reference images inline without setting a{" "}
<code>disposition</code> property on the attachment object.
</>
}
Expand Down
Loading