API Reference

Letters

Query and retrieve letters processed by ComplyPost. Letters include full classification data — sender, client, priority, category, summary, and any extracted deadlines.

GET/lettersBearer token

List letters with pagination and filtering.

Query parameters

Parameter	Type	Description
status	string	Filter by status: pending, confirmed, sent, bounced
clientId	string	Filter letters for a specific client
priority	string	Filter by priority: critical, high, medium, low
from	ISO 8601 date	Start date filter
to	ISO 8601 date	End date filter
page	integer	Page number (default: 1)
limit	integer	Results per page (default: 20, max: 100)

GET/letters/:idBearer token

Get a single letter with full classification data.

Example response

JSON

{
  "data": [
    {
      "id": "let_abc123",
      "batchId": "bat_xyz789",
      "status": "confirmed",
      "sender": "HMRC",
      "recipientCompany": "Johnson & Partners Ltd",
      "companyNumber": "12345678",
      "priority": "high",
      "category": "tax",
      "subject": "Self Assessment Tax Return Notice",
      "summary": "HMRC notice regarding the 2024/25 Self Assessment filing deadline.",
      "deadlines": ["2025-01-31"],
      "pages": 2,
      "receivedAt": "2025-01-15T10:30:00Z",
      "confirmedAt": "2025-01-15T10:45:00Z"
    }
  ],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 142,
    "totalPages": 8
  }
}

Related endpoints

GET/batchesList upload batches

GET/batches/:idGet batch details and processing progress

GET/clientsList clients

GET/calendarDeadlines extracted from letters

GET/auditImmutable audit trail

GET/analytics/overviewLetter processing statistics