Special inputs

File upload (fileUpload)

Lets users attach files. The element stores file metadata in the form data and can upload to a server through a data source.

Property	What it does
Accepted types	Restrict extensions/MIME types per HTML accept rules (e.g. .pdf,image/*)
Max files	How many files may be attached; further uploads are blocked at the limit
Max file size (MB)	Oversized files are rejected before upload
Dropzone text	Caption of the drag-and-drop area — a short, action-clear call to action
Upload data source	Source that receives the file — a POST (or configured method) with FormData
Upload form field name	The FormData field name for the file (e.g. file)
Download data source / Delete data source	Sources for fetching and removing stored files; the file key is passed via the key field below
File key / name / size / type field	Field names in the server's file object (default: key, name, size, contentType)

Without an upload data source, the file never leaves the browser

Only local metadata (name/size/type) is kept as the field's value — the field can look "filled in" while your backend never receives the actual bytes. Set Upload data source whenever the file must be stored server-side.

A few things worth knowing before you brief your developer:

• Uploads are always sent as multipart/form-data with a single field (its name is Upload form field name) — never JSON, never base64. Any Request body template configured on the upload source is ignored; only {placeholders} in its URL are used.
• With Max files > 1, files upload as separate sequential requests, not one batch call.
• There's no upload progress percentage — only pending/ready/error per file — and no resumable/chunked upload.
• The field's value in the form result is whatever your endpoint's response contained (the File key / name / size / type field properties), never the file's bytes.

For the exact request/response JSON your backend must implement, see File upload requests in the developer docs.

Typical setup — CV upload:

• Name: cvFile, Accepted types: .pdf, Max size: 5 MB, Required: on.
• Upload data source: uploadDocument (a REST source configured by your developer).

Check with expressions:

visibleIf on "Continue" hint:  isEmpty({cvFile})
len({attachments}) > 0         → at least one file attached

Signature pad (signaturePad)

A draw area for a handwritten signature (mouse or touch). The value is the signature image data, stored under the element's name and submitted with the form.

Property	What it does
Pen / background color	Drawing style
Clear button	Lets the user retry
Required	Signature must be present before submit

Use it at the end of agreements together with a Single checkbox ("I confirm the data is correct").