Document file rules

Filename characters, size limits, accepted types, and upload error codes for End User Onboarding

Before storing a document, the Upload a document for an application endpoint validates the filename and file bytes.

For upload steps, see Upload documents.

Read limits from the schema

Each file field can set its own types and size. Retrieve the application schema (GET /v1/onboarding/partner/applications/{applicationId}/schema) and read x-fileUpload on the target field:

"genericFileUploadBusinessRegistration": {
  "x-fileUpload": {
    "acceptedTypes": ["application/pdf", "image/jpeg", "image/png"],
    "maxSizeMb": 10
  }
}

If x-fileUpload is absent, the API uses the defaults in the following tables.

Filename

The API keeps the last path component of fileName when it contains / or \, then trims spaces at each end before validating the remaining name. For example, folder/passport.pdf is stored as passport.pdf.

Rule	Value
Length	1 to 255 characters after path components are removed and spaces are trimmed
Characters	Letters, numbers, spaces, hyphens (-), underscores (_), dots (.), and parentheses (())
Example	Ownership Chart (1).pdf

Commas, quotes, and other punctuation outside the allowlist fail the character check if they remain in the filename.

File type

The API reads magic bytes in fileContent. It doesn’t trust the Content-Type header.

Known signatures are PDF, JPEG, PNG, ZIP (Office Open XML), and OLE2 (legacy Office). A file with no matching signature returns unrecognized_type.

Source	Accepted types
Field x-fileUpload.acceptedTypes	The types listed on that field
No x-fileUpload	application/pdf, image/jpeg, image/png

Office files (DOC, XLS, DOCX, XLSX) pass only when the field schema lists those types. The default list doesn’t include them.

File size

Source	Limit
Field x-fileUpload.maxSizeMb	That value in megabytes
No x-fileUpload	10 MB

A file over the limit returns too_large.

Error codes

The following checks normally return HTTP 400 with numeric code 181102. The body includes errors with field and code.

field	code	When
fileName	required	fileName is missing or blank
fileName	too_long	Name is longer than 255 characters
fileName	invalid	Name is empty after path components are removed
fileName	invalid_characters	Name has a character outside the allowlist
fileContent	required	fileContent is missing
fileContent	empty	File has zero bytes
fileContent	unrecognized_type	File bytes don’t match a known type
fileContent	not_accepted	Type isn’t in the field’s x-fileUpload.acceptedTypes
fileContent	too_large	File is larger than x-fileUpload.maxSizeMb (default 10 MB)