Send a letter immediately
const url = 'https://api.tryletterhead.com/api/v3/letters/example/actions/send-now';const options = { method: 'POST', headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'}, body: '{"api":true,"channel":"an-example-channel","segment":0,"subject":"Who doesn\'t love a good movie?"}'};
try { const response = await fetch(url, options); const data = await response.json(); console.log(data);} catch (error) { console.error(error);}curl --request POST \ --url https://api.tryletterhead.com/api/v3/letters/example/actions/send-now \ --header 'Authorization: Bearer <token>' \ --header 'Content-Type: application/json' \ --data '{ "api": true, "channel": "an-example-channel", "segment": 0, "subject": "Who doesn'\''t love a good movie?" }'Send an already-drafted letter right away: its publication date is stamped at the current instant and the send is queued directly, bypassing the normal scheduling lead time. Use this when you want the letter to go out as soon as the request succeeds, rather than at a scheduled time.
A/B test letters are rejected — send those through the normal scheduling flow instead.
Authorizations
Section titled “Authorizations ”Parameters
Section titled “ Parameters ”Path Parameters
Section titled “Path Parameters ”The letter’s unique identifier — an alphanumeric string around ten characters, e.g. ludctamgd6.
Request Body required
Section titled “Request Body required ”object
Required. Set to true to authenticate with an API key.
The channel’s slug.
The integer identifier of your target segment, which is either all or a subset of your target channel.
(optional) Override the letter’s subject line for this send.
Example
{ "api": true, "channel": "an-example-channel", "segment": 0, "subject": "Who doesn't love a good movie?"}Responses
Section titled “ Responses ”The letter is being sent
object
object
Example
{ "items": { "uniqueId": "ludctamgd6", "publicationDate": "2026-05-06 05:53:05" }, "message": "Your letter is being sent now.", "total": 0}Still can’t find what you need? Contact support.