# Upload a KYC document

Uploads a KYC document for the customer via file upload (multipart/form-data).
The document type must match one of the types listed in the customer's kyc array
(e.g., ccmei, selfie, cnh). After upload, the document undergoes asynchronous review.
Track the result via the customer.kyc_updated webhook or by retrieving the customer
with GET /customers/{customer_id}.

Endpoint: POST /customers/{customer_id}/documents
Version: 2026-03-01
Security: bearerAuth

## Path parameters:

  - `customer_id` (string, required)
    Example: "cust_550e8400e29b41d4a716446655440000"

## Header parameters:

  - `Idempotency-Key` (string)
    Unique string for idempotent POST requests. Cached for 24 hours.

## Request fields (multipart/form-data):

  - `type` (string, required)
    KYC document type (e.g., ccmei, selfie, identity_card_front)

  - `file` (string, required)
    Document file (PDF, JPEG, or PNG)

## Response 201 fields (application/json):

  - `id` (string, required)

  - `type` (string, required)
    Document type
    Example: "ccmei"

  - `status` (string, required)
    Document status
    Enum: "submitted", "approved", "rejected"

  - `uploaded_at` (string, required)

  - `created_at` (string, required)

  - `updated_at` (string, required)

## Response 400 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)

## Response 401 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)

## Response 404 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)

## Response 422 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)

## Response 429 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)

## Response 500 fields (application/problem+json):

  - `type` (string, required)
    URI identifying the error type

  - `title` (string, required)
    Short, human-readable summary of the problem type

  - `status` (integer, required)
    HTTP status code

  - `detail` (string, required)
    Human-readable explanation specific to this occurrence

  - `instance` (string)
    URI identifying this specific occurrence

  - `code` (string)
    Machine-readable subtype code

  - `param` (string)
    The request parameter that caused the error

  - `errors` (array)
    Field-level validation errors

  - `errors.param` (string, required)

  - `errors.detail` (string, required)

  - `errors.code` (string)