Accessibility

PDF/UA Auto-Tagging (Accessibility)

Converts a PDF into a PDF/UA-1 compliant document with proper structure tags for screen readers and assistive technologies.

How it works

Layout analysis — OCR and layout models identify structural elements: headings, paragraphs, lists, tables, and artifacts.
Semantic tagging — Elements are mapped to the PDF structure tree with correct roles and logical reading order.
Output — Returns the tagged PDF with embedded PDF/UA metadata.

Capabilities

Feature	Description
Heading detection	Assigns H1–H6 roles, handles multi-column layouts
List semantics	Recognizes ordered and unordered lists
Table structure	Tags tables with row, cell, and scope attributes
Reading order	Reflows content logically for assistive technologies
Annotation handling	Integrates comments and form widgets into the structure tree
Artifact cleanup	Marks decorative elements to be skipped by screen readers

The output meets PDF/UA-1 validation requirements for WCAG 2.2, ADA, and Section 508 compliance.

post/api/accessibility/autotag

Request

Base URL: http://localhost:5000
URL: http://localhost:5000/api/accessibility/autotag
Auth: one of:
- API key in header Authorization
- HTTP bearer

Headers

nutrient-pdf-passwordstring

The PDF document password.

The value can be either a plain-text password or a base64 encoded password in a form base64:<encoded-password>. Use the Base64 encoding if your password contains characters that are not allowed in HTTP header or would be otherwise mangled (e.g. trailing or leading spaces)

If the document is password protected, any operations performed on it require supplying a password.

Request body

passwordstring

The password for the input file. The nutrient-pdf-password header takes precedence if both are provided.

conformance'pdfua-1'

Example request

{
  "file": {
    "url": "https://remote-file-storage/input-file"
  }
}

Response

The PDF/UA-1 compliant document

Changes

No recorded changes to this operation across all 1 revision of this API.