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Create a transactional email draft

POST
/api/v3/transactionals/actions/draft
curl --request POST \
--url https://api.tryletterhead.com/api/v3/transactionals/actions/draft \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data '{ "api": true, "channel": "an-example-channel", "subject": "Your password reset link", "html": "<!DOCTYPE html><html><body><h1>Reset your password</h1></body></html>", "tags": [ "password-reset" ] }'

Creates a transactional email draft (a private, tagged Letter) without sending it.

Authorization: Bearer token (company-level API key). The caller must be a company administrator for the channel’s owning company.

Feature flags: Requires both companyAudienceSending and transactionalEmail to be enabled.

Note: Recipient fields (to, toName, substitutionData) are ignored when drafting — only channel, subject, html, and tags are used. They may be sent (and are validated if present) but have no effect until the draft is sent.

Success: 201 Createditems.uniqueId is the created draft Letter’s id.

Media type application/json
object
api

Required. Set to true to authenticate with an API key.

boolean
channel

The channel you are drafting under (used for sender identity). Channel slug.

string
subject

The email subject. Max 191 chars; must contain a non-whitespace character.

string
html

The full HTML body of the email. Bring your own HTML.

string
tags

Transactional type tags, used for metric rollups. Required: 1-20 items, each 60 chars or fewer. Trimmed and de-duplicated case-insensitively.

Array<string>
Example
{
"api": true,
"channel": "an-example-channel",
"subject": "Your password reset link",
"html": "<!DOCTYPE html><html><body><h1>Reset your password</h1></body></html>",
"tags": [
"password-reset"
]
}

201 Created

Media type application/json
object
items
object
uniqueId
string
message
string
total
integer
Example
{
"items": {
"uniqueId": "6cuswtvr7p"
},
"message": "Transactional email draft created.",
"total": 0
}

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