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PDF Comment Markup

Draw review-style side comments, arrows, and highlight regions on PDF pages

Apply markup overlays to an existing PDF.

Includes:

  • Highlight boxes for review focus
  • Side comment boxes with connector arrows
  • Left/right note placement for editorial workflows

Example Results

2 examples

Right-Side Review Notes

Adds highlight and right-side comment callout to a draft PDF

comment-markup-example1.pdf View File
View input parameters
{ "inputPdf": "/Users/quyue/www/elysia-tools/public/samples/pdf/outline-bookmarks-example1.pdf", "markupsJson": "[{\"page\":1,\"kind\":\"highlight\",\"x\":14,\"y\":20,\"w\":45,\"h\":8,\"text\":\"Need stronger source\"},{\"page\":1,\"kind\":\"comment\",\"x\":20,\"y\":38,\"w\":34,\"h\":9,\"text\":\"Clarify this claim with data.\",\"side\":\"right\"}]", "highlightOpacity": 0.26, "noteOpacity": 0.95, "noteWidthRatio": 0.22 }

Left-Side Editorial Notes

Uses left-side note placement and lower highlight opacity

comment-markup-example2.pdf View File
View input parameters
{ "inputPdf": "/Users/quyue/www/elysia-tools/public/samples/pdf/outline-bookmarks-example2.pdf", "markupsJson": "[{\"page\":1,\"kind\":\"comment\",\"x\":16,\"y\":30,\"w\":26,\"h\":8,\"text\":\"Move this paragraph under Architecture.\",\"side\":\"left\"},{\"page\":1,\"kind\":\"highlight\",\"x\":18,\"y\":52,\"w\":38,\"h\":10}]", "highlightOpacity": 0.18, "noteOpacity": 0.86, "noteWidthRatio": 0.28 }

Click to upload file or drag and drop file here

Maximum file size: 120MB Supported formats: application/pdf

Key Facts

Category
Document Tools
Input Types
file, textarea, number
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

The PDF Comment Markup tool allows you to professionally annotate documents by applying highlight regions and side-positioned comment boxes with connector arrows, perfect for editorial and review workflows.

When to Use

  • •When you need to provide structured feedback on draft documents for colleagues or clients.
  • •When you want to highlight specific sections of a PDF while keeping the main text clean.
  • •When you need to organize editorial notes on either the left or right margins of a page.

How It Works

  • •Upload your target PDF document using the file input.
  • •Define your annotations in the Markups JSON field, specifying the page, markup type, coordinates, and text content.
  • •Adjust the opacity and width settings to ensure your comments are legible and visually aligned.
  • •Process the file to generate a new PDF with your review annotations permanently applied.

Use Cases

Academic peer review for marking up research papers with specific evidence requests.
Corporate document editing for providing clear, side-aligned feedback on policy drafts.
Legal contract review for highlighting clauses that require further clarification or revision.

Examples

1. Right-Side Review Notes

Background
A researcher is reviewing a draft paper and needs to request more data for a specific claim.
Problem
The reviewer needs to highlight the claim and add a clear, side-aligned comment without obscuring the text.
How to Use
Upload the PDF and define a highlight region and a right-side comment box in the JSON input.
Example Config
[{"page":1,"kind":"highlight","x":14,"y":20,"w":45,"h":8,"text":"Need stronger source"},{"page":1,"kind":"comment","x":20,"y":38,"w":34,"h":9,"text":"Clarify this claim with data.","side":"right"}]
Outcome
A PDF is generated with a subtle highlight over the claim and a professional comment box on the right margin.

2. Left-Side Editorial Notes

Background
An editor is restructuring a technical manual and needs to move paragraphs between sections.
Problem
The editor needs to leave instructions on the left margin to keep the right side clear for reading.
How to Use
Configure the JSON to place comments on the left side and apply a light highlight to the target paragraph.
Example Config
[{"page":1,"kind":"comment","x":16,"y":30,"w":26,"h":8,"text":"Move this paragraph under Architecture.","side":"left"},{"page":1,"kind":"highlight","x":18,"y":52,"w":38,"h":10}]
Outcome
The document is updated with clear editorial instructions on the left side, facilitating an easier restructuring process.

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FAQ

Can I place comments on both sides of the page?

Yes, you can specify 'left' or 'right' in the side property within your JSON configuration for each comment.

What file formats are supported?

This tool exclusively supports PDF files for both input and output.

How do I control the transparency of the highlights?

Use the Highlight Opacity slider to adjust the visibility of your highlighted regions between 0.08 and 0.6.

Is the markup permanent?

Yes, the tool generates a new PDF file with the annotations flattened into the document.

What happens if my JSON syntax is incorrect?

The tool requires valid JSON format; ensure all brackets and quotes are properly closed to avoid processing errors.

API Documentation

Request Endpoint

POST /en/api/tools/pdf-comment-markup

Request Parameters

Parameter Name Type Required Description
inputPdf file (Upload required) Yes -
markupsJson textarea Yes -
highlightOpacity number No -
noteOpacity number No -
noteWidthRatio number No -

File type parameters need to be uploaded first via POST /upload/pdf-comment-markup to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-pdf-comment-markup": {
      "name": "pdf-comment-markup",
      "description": "Draw review-style side comments, arrows, and highlight regions on PDF pages",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=pdf-comment-markup",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]