Free, Private PDF Tools — Convert to Dark Mode in Seconds
DimlyPDF is a privacy-first PDF toolkit: convert PDF to dark mode, compress, merge, split, export pages as images, add page numbers, and rotate — all without uploading files to a server. Every tool runs locally in your browser using WebAssembly, so your documents never leave your device.
Popular tools
- Convert PDF to dark mode — rewrite a PDF to a true dark background with 4 themes; text and links stay selectable.
- Compress PDF — reduce file size by optimizing structure, with no blurry re-encoding.
- Merge PDF files — combine multiple PDFs into one, drag to reorder before merging.
- Split PDF — extract specific pages or page ranges into new files.
- PDF to JPG / PNG — export pages as high-resolution images, bundled as a ZIP.
- Add page numbers — stamp customizable page numbers in any position.
- Rotate PDF — fix page orientation 90, 180, or 270 degrees.
Why DimlyPDF?
- 100% private — files are never uploaded to a server.
- Runs entirely in your browser, powered by WebAssembly (MuPDF, pdf-lib, pdf.js).
- No account, no sign-up, and no usage caps beyond a 100 MB per-file limit.
- Works in Chrome, Firefox, Safari, and Edge on desktop and mobile.
- Always free.
Guides
- How to read PDFs at night without eye strain
- PDF dark mode vs blue light filters
- Why Windows dark mode does not apply to PDFs
- Firefox PDF viewer has no dark mode
Frequently asked questions
How do I convert a PDF to dark mode?
Open the PDF Dark Mode tool, upload your file, pick a theme (OLED Black, Midnight, Warm Sepia, or Dim Grey), and download. Text and links stay selectable — your file never leaves your browser.
Are my PDF files uploaded to a server?
Never. All DimlyPDF tools run locally in your browser using WebAssembly. Your documents stay on your device.
Is DimlyPDF really free?
Yes — every tool is free with no account, no credits, and no usage caps beyond the 100 MB per-file limit.
What PDF tools are available?
Dark mode conversion, compress, merge, split, PDF to JPG/PNG, add page numbers, and rotate pages — all in one private toolkit.
Why use DimlyPDF instead of other online PDF sites?
Most online PDF tools upload your files to their servers. DimlyPDF processes everything in-browser, so contracts, medical records, and personal documents stay private.
Does dark mode work for reading PDFs at night?
Yes. Converting to a true dark-mode PDF is more comfortable than screen filters alone — especially for long reading sessions.