selenium print page to PDF in headless chrome: how to do

TL;DR

Headless Chrome exposes page printing through the DevTools protocol, which selenium can reach with execute_cdp_cmd('Page.printToPDF', {...}); the command returns base64 PDF bytes you decode and write to a file. This bypasses the print dialog entirely, which is what you want in automation. Tune paperWidth, paperHeight, margins, and printBackground in the params to match what the feature under test expects.

The query

selenium print page to PDF in headless chrome: how to do

Use this when

• Testing a "download as PDF" or print-stylesheet feature
• Archiving rendered pages as PDFs in a pipeline
• Verifying PDF output without a human clicking print

Not for

• Headed-browser print dialog automation
• Generating PDFs outside a browser (use a PDF library)
• Firefox PDF printing

Steps

1. Ensure the driver is headless Chrome (CDP commands need a Chromium-based session) and the page is fully loaded. Expected output: driver.execute_cdp_cmd is available and the page render is complete.
2. Call Page.printToPDF via execute_cdp_cmd with your paper size and margin options; capture the returned base64 data. Expected output: a base64 string is returned without errors.
3. Decode the base64 payload and write it to a .pdf file, then open it to confirm content and layout. Expected output: a valid PDF file renders the page as expected.
4. Assert on the PDF in your test (file exists, non-trivial size, or text extraction matches key content). Expected output: the test verifies the PDF rather than just its existence.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_pFdqJ8-i47DFq5R02MPjug