Known Limitations
Chromium only
Section titled “Chromium only”Press.js currently supports Chromium only (via Playwright). Firefox and WebKit are not supported. This is because the pagination engine relies on Chromium-specific rendering behavior and PDF export.
No interactive content in PDF
Section titled “No interactive content in PDF”Interactive elements are not preserved in PDF output:
- Forms and input fields become static text
- Buttons lose their click behavior
- CSS animations and transitions are frozen at their final state
- JavaScript-driven interactions do not function
This is a fundamental constraint of the PDF format, not specific to Press.js.
Preview vs. production differences
Section titled “Preview vs. production differences”While the development preview is designed to match the CLI render output, some differences may occur:
- Your development browser may have extensions installed that alter page appearance
- The preview runs in your browser’s rendering engine; the CLI uses headless Chromium, which has slight differences in compositing
- Even with identical font files, text rendering varies by OS — macOS uses Core Text, Linux uses FreeType/Fontconfig, and Windows uses DirectWrite. These engines differ in glyph shaping, kerning, and metrics, which can affect pagination and layout
Large documents
Section titled “Large documents”Very large documents (100+ pages with dense content) may experience longer render times. The pagination engine iterates to resolve overflow, and each iteration requires re-measuring the page layout.