Compare PDFs

Page-level diff of two PDFs: which pages are identical, modified (with a unified text diff and similarity score), added or removed. Returns report.json, optionally with rendered diff images highlighting changed pixels.

Free on the API and MCP server — generous limits, files deleted within an hour, content never logged.

Server
This one runs on our servers — under the same privacy rules.
Files are virus-scanned before processing, stored encrypted, and deleted within 1 hour. Content is never logged. And it's free: 250 operations a day, every day, plus burst on spare capacity.

Compare PDFs needs server-grade machinery (heavy conversion, OCR or cryptography the browser can't do safely), so it runs through the REST API and the MCP server instead of an uploader. One free key drives both — get yours in about a minute.

REST API

curl -X POST https://api.pdfmcp.org/v1/jobs \
  -H "X-API-Key: pdfmcp_live_YOUR_KEY" \
  -F files=@your-file.pdf -F op=compare_pdfs -F include_diff_images=False

Submit → poll → download. Full walkthrough in the REST API quickstart guide.

MCP (for AI agents)

{
  "mcpServers": {
    "pdfmcp": {
      "url": "https://mcp.pdfmcp.org/mcp",
      "headers": {
        "X-API-Key": "pdfmcp_live_YOUR_KEY"
      }
    }
  }
}

Paste into Claude, Cursor, VS Code, ChatGPT and 9 more clients — setup guides for every major MCP client.

By using the API or MCP server you agree to the Terms of Service and Acceptable Use Policy. Files you send are deleted within an hour; see the Privacy Policy.

How compare pdfs works here

Page-level diff of two PDFs: which pages are identical, modified (with a unified text diff and similarity score), added or removed. Returns report.json, optionally with rendered diff images highlighting changed pixels. Server-side, the job passes the security inspection gauntlet first (antivirus, structural and active-content checks), runs in a sandboxed worker, and the result waits for you for exactly one hour.

People often pair this with ocr — searchable pdf and pdf info & metadata — same deal there: free, private, no sign-up.

Parameters

ParameterTypeDefaultDescription
include_diff_imagesbooleanoptionalFalse

FAQ

Is Compare PDFs free?

Yes — completely free, with no watermark, no sign-up and no trial clock. On the API/MCP side every key gets 250 guaranteed operations a day plus unlimited burst operations on spare capacity. See the pricing page for the full (short) policy.

What happens to my file?

You send it to the pdfmcp API/MCP server over HTTPS. It is virus-scanned and inspected before processing, stored in an encrypted temporary volume, and automatically deleted within 1 hour of the job finishing. We never log file content or file names.

Can I automate Compare PDFs with an AI agent or code?

Yes — the exact same operation is a tool on the pdfmcp MCP server (for Claude, Cursor, ChatGPT and other agents) and an endpoint on the REST API. One free key works for both; the guides walk you through setup in about a minute.

Are there limits?

Files up to 100 MB and 500 pages. Web tools are additionally bounded by your device's memory. The caps exist to stop abuse and keep the shared machine fair — they are not a paywall, and there is no paid tier to unlock.

Related tools

API · MCPOCR — searchable PDFMake a scanned PDF searchable: pages without a text layer are OCR'd with Tesseract and gain an invisible text layer; pages that already have text are passed through and reported as skipped.On-devicePDF info & metadataPage count, page sizes, metadata, encryption status as JSON.API · MCPExtract imagesPull all embedded images out of a PDF (ZIP, original formats).API · MCPExtract tables (JSON + CSV)Detect tables and return them as tables.json plus one CSV per table (ZIP).On-deviceExtract bookmarks / TOCReturn the document outline as JSON: level, title, target page.On-deviceExtract attachmentsPull all embedded file attachments out of the PDF (ZIP).

Browse the extract & ocr hub or the full tool index. Building something bigger? Read the features tour and the free usage policy.