Get an SMS campaign's non-delivery breakdown

GET

/api/v3/channels/{channelSlug}/letters/{letterUniqueId}/sms/delivery-errors

const url = 'https://api.tryletterhead.com/api/v3/channels/example/letters/example/sms/delivery-errors?api=true';
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}

curl --request GET \
  --url 'https://api.tryletterhead.com/api/v3/channels/example/letters/example/sms/delivery-errors?api=true' \
  --header 'Authorization: Bearer <token>'

One SMS campaign’s non-delivery breakdown for the campaign report’s delivery-errors card: the classes of failure and how many recipients each hit, most-affected first. Counts only — no recipient identity ever appears in the response.

This endpoint is gated behind an internal feature flag that is not yet enabled for any tenant. While it’s off, the endpoint returns an empty list.

v3 endpoints expect a company API key.

Authorizations

bearerAuth

Parameters

Path Parameters

channelSlug

required

string

The newsletter’s channel identifier (slug).

letterUniqueId

required

string

Unique id of the SMS campaign (letter).

Query Parameters

api

required

boolean

Required. Set to true.

Responses

200

200 OK

application/json

object

items

Array<object>

object

category

string

errorCode

string

affectedRecipients

integer

message

string

total

integer

Example

{
  "items": [
    {
      "category": "carrier_rejected",
      "errorCode": "30007",
      "affectedRecipients": 12
    }
  ],
  "message": "Ok",
  "total": 1
}

404

404 Not Found — channelSlug doesn’t match a channel this company owns, the letter isn’t found on this channel, or the letter isn’t an SMS campaign.

application/json

object

data

Array<object>

object

items

Array<object>

object

message

string

total

integer

Example

{
  "data": [],
  "items": [],
  "message": "Letter is not found on this channel.",
  "total": 0
}

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