Field Types & Coordinates

Field types

Type	Value filled by	Description
`signature`	Signer (draw or type)	Full signature image
`initial`	Signer (draw or type)	Initials only
`date`	System (auto)	Current date at time of signing — signer cannot edit
`text`	Signer	Free-form text input (up to 1000 chars)
`checkbox`	Signer	Boolean — check or uncheck

Coordinate system

All field positions use PDF points (1 point = 1/72 inch). The origin (0, 0) is the bottom-left corner of each page — this is the PDF standard, not a SignProof quirk.

┌──────────────────────────────┐ ← top of page (y = page height)
│                              │
│   ┌───────────────┐          │
│   │  field here   │          │
│   └───────────────┘          │
│   ↑                          │
│   (x=72, y=200)              │
│                              │
└──────────────────────────────┘ ← bottom of page (y = 0)

Common page sizes in points:

Page size	Width	Height
US Letter (8.5” × 11”)	612	792
A4 (210mm × 297mm)	595	842
Legal (8.5” × 14”)	612	1008

Field parameters

{
  "documentId": "doc_01HX...",
  "signerId": "sgn_01HX...",
  "type": "signature",
  "page": 1,
  "x": 72,
  "y": 72,
  "w": 200,
  "h": 60,
  "required": true
}

Parameter	Description
`page`	1-based page number
`x`	Left edge of the field in PDF points
`y`	Bottom edge of the field in PDF points
`w`	Width in PDF points
`h`	Height in PDF points
`required`	If `true`, signer cannot complete without filling this field

Converting screen coordinates to PDF coordinates

If you’re placing fields from a browser-rendered PDF, you need to convert screen pixels to PDF points. The formula accounts for the screen DPI and the PDF render scale:

function screenToPdf(
  screenX: number,
  screenY: number,
  screenPageHeight: number,
  renderScale: number    // e.g. 1.5 for 150% zoom
): { x: number; y: number } {
  const PDF_DPI = 72;
  const SCREEN_DPI = 96;

  // Convert screen pixels → PDF points
  const pdfX = (screenX / renderScale) * (PDF_DPI / SCREEN_DPI);

  // PDF y-axis is inverted (origin at bottom) — flip it
  const pdfY = ((screenPageHeight - screenY) / renderScale) * (PDF_DPI / SCREEN_DPI);

  return { x: Math.round(pdfX), y: Math.round(pdfY) };
}

The drag-drop field placer in the Console handles coordinate conversion for you. Use it to position fields visually without writing coordinate math.

Typical field sizes

These are sensible defaults — adjust to fit your document layout.

Field type	Recommended width	Recommended height
`signature`	180–250 pt	50–80 pt
`initial`	80–120 pt	40–60 pt
`date`	100–150 pt	20–30 pt
`text`	150–300 pt	20–30 pt
`checkbox`	16–20 pt	16–20 pt

Optional fields

Set required: false to make a field optional. The signer can complete it or leave it blank. At least one field per signer must be required (SignProof will reject an envelope where a signer has only optional fields).

Date format

date fields are auto-filled with the signing date in the format configured on your application (default: YYYY-MM-DD). The date is recorded at the moment the signer submits, in UTC.

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Guides

Field Types & Coordinates

Field types

Coordinate system

Field parameters

Converting screen coordinates to PDF coordinates

Typical field sizes

Optional fields

Date format

​Field types

​Coordinate system

​Field parameters

​Converting screen coordinates to PDF coordinates

​Typical field sizes

​Optional fields

​Date format

Field types

Coordinate system

Field parameters

Converting screen coordinates to PDF coordinates

Typical field sizes

Optional fields

Date format