Run preflight agents on a letter

POST

/api/v3/letters/{letterUuid}/agents/actions/run-preflight

curl --request POST \
  --url https://api.tryletterhead.com/api/v3/letters/example/agents/actions/run-preflight \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form api=true

• Production

Provided you have any preflight agents, this endpoint allows you to trigger them. The newsletter must be in a preflight status - that is, scheduling - for the agents to actually run.

v3 endpoints expect a company API key.

Authorizations

• bearerAuth

Parameters

Path Parameters

letterUuid

required

string

The letter’s unique identifier — an alphanumeric string around ten characters, e.g. ludctamgd6.

Request Body ^required

Media type multipart/form-data

object

api

required

When set to true, this endpoint will accept authorization with your API Key.

string

Example

true

Responses

201

Trigger Preflight Agents

Media type application/json

object

items

object

uniqueId

string

agentUniqueId

string

resourceType

integer

resourceUniqueId

string

status

integer

summary

string

nullable

validationCode

integer

dispatchedAt

string

nullable

startedAt

string

nullable

completedAt

string

nullable

judgments

Array<object>

object

createdAt

string

updatedAt

string

message

string

total

integer

Example

{
  "items": {
    "uniqueId": "vq5rnof1op",
    "agentUniqueId": "8vbkbo1yqz",
    "resourceType": 0,
    "resourceUniqueId": "35f725edbi",
    "status": 0,
    "summary": null,
    "validationCode": 200,
    "dispatchedAt": null,
    "startedAt": null,
    "completedAt": null,
    "judgments": [],
    "createdAt": "2026-03-26 15:02:52",
    "updatedAt": "2026-03-26 15:02:52"
  },
  "message": "",
  "total": 10
}