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. Keep it short and say what to do
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, so 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 or 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").