Signature Block - Flex Forms

The Signature block gives respondents an interactive canvas (mouse, trackpad, or touch). The stroke is smoothed and stored as a compact SVG string in the submission payload — not as a separate upload file. Optional download (SVG / WebP) is for the respondent’s browser only; it does not write to your media disk.

Business Use Cases

Contract Agreements

Collect an embedded signature on NDAs, service agreements, or B2B contracts.

Delivery Confirmations

Allow customers to sign a tablet upon receiving a high-value shipment.

Waivers & Liability

Require an electronic signature before participation.

Configuration & Usage

Deploy to Canvas

Drag the Signature block from the Component Catalog onto the Canvas.

Style the Canvas

Adjust pen color, width, and optional guidelines to match your brand.

Enforce Validity

Raise Min Strokes so a single accidental tap cannot pass validation.

Technical Configuration Schemas

Canvas & Aesthetics
Validation Rules
Download (optional)

string

HEX ink color (e.g. #000000).

float

Stroke thickness.

string

Canvas background. Leave empty for transparent SVG.

boolean

default:"false"

Full-screen signing mode on small screens.

boolean

default:"false"

Smooth stroke paths for a more natural look.

string

Optional browser download format (svg or webp). Does not change what is stored in the submission.

string

Filename prefix for the optional download.

Data Payload Architecture

Unlike File Upload / Voice Note, signatures are not staged to disk. The answer is the SVG markup string inside the submission payload (same on webhooks and in the database).

{
  "submission_id": "sub_883",
  "data": {
    "liability_signature": "<svg xmlns=\"http://www.w3.org/2000/svg\" ...>...</svg>"
  }
}

[
    'liability_signature' => '<svg xmlns="http://www.w3.org/2000/svg" ...>...</svg>',
]

Best Practices & FAQs

Stroke Validation

Set Min Strokes to at least 2 so a single tap cannot pass as a signature.

PDF overlays

Transparent SVG (empty background) overlays cleanly onto contract lines in generated PDFs. A solid background color makes overlays harder.

Last modified on September 7, 2026

​Business Use Cases

Contract Agreements

Delivery Confirmations

Waivers & Liability

​Configuration & Usage

​Technical Configuration Schemas

​Data Payload Architecture

​Best Practices & FAQs

Business Use Cases

Configuration & Usage

Technical Configuration Schemas

Data Payload Architecture

Best Practices & FAQs