Stamp, sign and check,
all your PDF work
right in the browser
No installation needed. Add a saved stamp or signature with one click, place O/X/V marks, draw freehand or add notes, then save one flattened PDF. Your files are processed only in the browser and are not uploaded to a server.
Windows 10/11 · Free · No installation needed— use the web app · View key features
Upload a PNG, then place it with one click
Save up to nine seals, signatures or approval stamps in your library and recall them instantly.
O/X/V marks, freehand pen and text
Place approvals, rejections, checks, drawings and comments anywhere on the PDF.
Processed only in your browser
Sensitive documents stay on your device and are never sent to an external server.
Everything you need to mark up a PDF,
together in one workspace
Open and save PDFs
Drag and drop a PDF or press Ctrl+O to open it, then use Ctrl+S to save. The File System Access API can also overwrite the file in its original location.
Drag and copy document text
Use the selection tool to drag over and copy text. Even fragmented PDF text is grouped cleanly by line or box.
Stamp and signature library
Upload stamp PNGs and signature images, then place them with one click. They are stored in IndexedDB for your next visit.
O/X/V check marks
Quickly add approval, rejection and check marks, then adjust their color, size and position.
Free-form text notes
Type comments, names and notes anywhere on the PDF. Korean text is embedded directly in the saved document.
Freehand drawing
P switches to the pen for freehand drawing. Fine-tune color and stroke width in 1 pt increments.
Full-screen presentation
Use the Presentation button in the Windows app or press F5 to start full screen from the current page. Navigate with the arrow keys, Page Up/Down, Space or the mouse wheel, and press Esc to exit.
Color, size and stroke width
Choose from five presets or pick a custom value. − / + adjust by 1 pt, while the slider handles larger changes.
Unlimited undo and redo
Ctrl+Z / Ctrl+Y for unlimited undo and redo. You can also readjust position, size and color after placing an annotation.
Save one flattened PDF
Flatten every annotation and save it as original-name_signed.pdf. The recipient can open it in any standard PDF viewer.
Page management · delete from the preview
Right-click the page you want to drop in the left preview and choose Delete page, or click the thumbnail and press Delete. Blank pages from a bad scan and duplicate cover sheets go away on the spot. Drag thumbnails to reorder, and rotate, merge or extract pages from the same row of buttons.
14 languages
Korean, English, Japanese, Chinese (Simplified and Traditional), Spanish, Portuguese, French, German, Russian, Vietnamese, Indonesian, Italian and Thai. Pick one during installation and change it any time in settings.
Finish your PDF markup in three steps
The workflow is simple enough for a first-time visitor to stamp, check, annotate and download a PDF in about 30 seconds.
Open a PDF
Drag a PDF into the window or click “Browse PDF files.”
- Drag-and-drop support
- Ctrl+O to open instantly
- Review multiple PDFs one after another
Stamp, check and add notes
Choose a tool from the sidebar or switch with a shortcut, then click or drag where you want to place it.
- Alt+1~9 to recall stamps 1–9
- O · X · V to add check marks
- P pen · T text note
Save one flattened PDF
Ctrl+S or the Save button creates a flattened PDF with every mark embedded.
_signedsuffix added automatically- Korean font embedded with NotoSansKR
- Opens in any standard PDF viewer
Keyboard shortcuts for faster approvals
Complete the main actions from the keyboard without moving the mouse through every repeated approval task.
Frequently asked questions
Is my PDF uploaded or stored on a server?
No. BLUE PDF runs entirely in your browser. PDFs and stamp images are not sent to an external server; they are handled only in browser memory and IndexedDB on your device, making it suitable for sensitive approval documents.
Can I use my saved stamps on another computer?
Stamps are currently stored in IndexedDB in the browser you are using. To use them on another computer or browser, upload the stamp PNG there once more.
Will Korean text notes break in the saved PDF?
No. NotoSansKR is embedded in the PDF so Korean text remains intact. The server must provide NotoSansKR-Regular.ttf and NotoSansKR-Bold.ttf; those font files are not needed if you use only Latin letters and numbers.
Does it work on mobile?
You can view PDFs and add simple marks in a mobile browser. For stamps, text and multi-page work that requires precise placement, we recommend a desktop or a tablet with a keyboard.
Which browsers are recommended, and is there a file-size limit?
Chrome, Edge and Whale 86+ can overwrite the original file through the File System Access API. Safari and Firefox save a new file instead. Since nothing is uploaded, the practical limit depends on browser memory: PDFs of several dozen megabytes usually work well, while files over 100 MB may render slowly depending on device performance.
Does the recipient also need BLUE PDF?
No. The saved file is a standard flattened PDF with every stamp, mark and note embedded. Recipients can open it in Acrobat Reader, a browser PDF viewer or any other standard PDF tool.
Start in your browser now
Install the Windows desktop app or launch the browser version instantly.
Windows 10/11 (64-bit) · Free · Ready after installation
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