PDF Dark

What is PDF Dark?

PDF Dark is a free, browser-side tool for reading PDFs in dark mode or night mode. Drop a PDF, pick a theme, and read it on a dark background. The file never leaves the browser: no upload, no signup, and no install.

What PDF Dark does

Themes are Midnight, Sepia, Solarized, and OLED, with darkness and warmth sliders. Text and background go dark. Photos can keep their original colors, white screenshots and diagrams can be inverted to blend with the page, and bright colorful images can get a gentle dim. The Images toggle can force Original or Inverted. A download saves the dark theme into the file so it stays dark in other readers, including print. Scanned pages are treated as images and inverted uniformly, including handwriting and old yellowed scans. The OLED theme renders the background as pure black. There is no size limit. The conversion runs in the browser via a Web Worker.

Who PDF Dark is for

PDF Dark is for reading PDFs at night, on a phone, or in Chrome, Firefox, Safari, or Edge, including Safari on iPhone and iPad.

How PDF Dark works

Drag and drop a PDF, or click to browse. Pick Midnight, Sepia, Solarized, or OLED, then tune darkness and warmth. Page through with a keyboard, touch, or the page controls. To keep a file, invert the colors and download it. Print from that downloaded copy, because the colors are written into the file. Mozilla PDF.js renders the PDF. pdf-lib is used to stitch themed pages into a downloadable file. The dark-mode algorithm is per-pixel brightness mapping in a Web Worker.

Key features

• Midnight, Sepia, Solarized, and OLED, plus darkness and warmth sliders.
• Photos can keep original colors. The Images toggle can force Original or Inverted.
• 100% in the browser, with no upload, no signup, and no size limit.
• A downloaded dark PDF stays dark in other readers, and the print output is dark too.
• Scanned PDFs are inverted uniformly, including handwriting and yellowed scans.
• Open source under the MIT license.
• Safari on iOS can open a PDF on the page, with no app install.
• Sentry is activated only when something breaks, with content masked.

Facts from pdfdark.org, checked 14 October 2026

• Hosting is Vercel. Error monitoring is Sentry, and the replay masks content so it never captures the PDF.
• The about page says there is no paywall on the conversion. If hosting stops being free, a small ad on the landing page is the likely next step, never inside the PDF viewer.
• The codebase is on GitHub under the MIT license, including the brightness-mapping algorithm and the Sentry masking config.
• The about page says PDF Dark runs on free-tier hosting.

Written from PDF Dark's own website (Homepage, About). The maker can claim this listing to edit it.