Documents

Each proprietor needs three documents before a registration can be submitted:

`kind`	What it is
`means_of_id`	The proprietor’s paper NIN slip. CAC doesn’t accept other IDs or the digital NIN slip.
`passport`	A clear, recent passport photograph of the proprietor.
`signature`	The proprietor’s signature on plain paper.
`supporting_document`	Optional. A professional certificate, when a name check says `requires_certificate`.

Upload each as multipart form data. Files can be up to 5 MB.

curl https://api.fastcac.com/v1/registrations/$REG_ID/documents \
  -H "Authorization: Bearer $FASTCAC_KEY" \
  -F kind=passport -F proprietor=0 -F file=@passport.jpg

string

required

means_of_id, passport, signature or supporting_document.

integer

default:"0"

The proprietor’s index in proprietors.

file

required

The document, at most 5 MB.

Response (201)

{
  "object": "document",
  "id": "doc_1f3vn4z6FzDYjcbdUYUVtK",
  "registration_id": "reg_5iLOZvP27DZ2zDQTjOzY1O",
  "proprietor": 0,
  "kind": "passport",
  "filename": "passport.jpg",
  "content_type": "image/jpeg",
  "size": 8,
  "status": "verified",
  "reason": null,
  "created_at": "2026-10-23T22:06:51Z"
}

Each upload is checked and comes back verified or rejected with a reason. A document.verified or document.rejected webhook follows. To replace a document, upload another of the same kind; the latest one counts.

Rejected (test mode, ?simulate=rejected)

{
  "object": "document",
  "id": "doc_4WXZ9tOUBC1o9hp6qkLXnB",
  "registration_id": "reg_2G3HOP060V7RRGlHZcehtP",
  "proprietor": 0,
  "kind": "passport",
  "filename": "passport.jpg",
  "content_type": "image/jpeg",
  "size": 8,
  "status": "rejected",
  "reason": "The image is too blurred to read. Upload a clearer photo.",
  "created_at": "2026-10-23T22:06:51Z"
}

A registration can’t be submitted until each proprietor’s latest document of every required kind is verified:

400

{
  "error": {
    "type": "invalid_request_error",
    "code": "registration_incomplete",
    "message": "Still needed: proprietors[0].documents.passport, proprietors[0].documents.signature.",
    "param": "proprietors[0].documents.passport",
    "request_id": "req_Zz1mlZtOn3SbpYf5CW7K3nvy"
  }
}

List a registration’s documents with GET /v1/registrations/{id}/documents.

Error `code`	Meaning
`file_too_large`	Over 5 MB.
`file_empty`	The file has no content.
`registration_locked`	The registration isn’t editable now.
`field_not_queried`	The registration is queried, and CAC didn’t ask about this document.

Get started

Registering a business

Webhooks

API basics

Going live