# CorePDFTools

> Free, privacy-first PDF tools that run entirely in your web browser. Files are never uploaded to a server — all processing happens locally on the user's device. No sign-up, no daily limits, no watermarks.

CorePDFTools is a collection of client-side PDF utilities. Every operation (merging, splitting, compressing, converting, signing, protecting, OCR) is performed in-browser using JavaScript and WebAssembly. This makes it suitable for sensitive documents such as IDs, contracts and financial statements, which never leave the user's device.

## Tools
- [Merge PDF](https://corepdftools.com/merge.html): Combine multiple PDFs into one file in your browser.
- [Split PDF](https://corepdftools.com/split.html): Split a PDF by page range or extract every page.
- [Compress PDF](https://corepdftools.com/compress.html): Shrink PDF file size while keeping text sharp and selectable.
- [Compress PDF to 100KB](https://corepdftools.com/compress-to-100kb.html): Compress a PDF to an exact target size (100KB, 200KB, 300KB, 500KB) for exam and government portal uploads.
- [Rotate PDF](https://corepdftools.com/rotate.html): Rotate pages and save the rotation permanently.
- [Organize PDF Pages](https://corepdftools.com/organize.html): Reorder and delete pages visually.
- [JPG to PDF](https://corepdftools.com/jpg-to-pdf.html): Convert JPG/PNG images into a single PDF.
- [PDF to JPG](https://corepdftools.com/pdf-to-jpg.html): Convert each PDF page to a high-quality JPG image.
- [Protect PDF](https://corepdftools.com/protect.html): Password-protect and encrypt a PDF on your device.
- [Sign PDF](https://corepdftools.com/sign.html): Draw and place a signature on a PDF.
- [Watermark PDF](https://corepdftools.com/watermark.html): Add a text watermark across every page.
- [OCR PDF](https://corepdftools.com/ocr.html): Extract text from scanned PDFs using in-browser OCR.

## Key pages
- [How it works](https://corepdftools.com/how-it-works.html): Plain-language explanation of the in-browser processing model and the libraries used (pdf-lib, PDF.js, Tesseract).
- [FAQ](https://corepdftools.com/faq.html): Common questions about privacy, file uploads, compression quality and browser support.
- [Blog](https://corepdftools.com/blog/index.html): Guides on compressing PDFs to size limits, merging without quality loss, signing, and privacy.
- [Privacy Policy](https://corepdftools.com/privacy.html): Files are never uploaded; the site uses Google Analytics, AdSense and Adsterra with cookies.

## Key facts
- All processing is client-side; no file is ever uploaded.
- Free and unlimited; no account required.
- Compression downsamples embedded images while keeping text selectable; it never rasterizes text and never returns a file larger than the original.
- Works on desktop and mobile browsers (Chrome, Edge, Firefox, Safari).
- Contact: contactus@corepdftools.com

## Blog articles
- [How to Add a Watermark to a PDF](https://corepdftools.com/blog/add-watermark-to-pdf.html): Stamp text like CONFIDENTIAL or DRAFT across every page of a PDF, free and in your browser.
- [Are Online PDF Tools Safe? What to Check First](https://corepdftools.com/blog/are-online-pdf-tools-safe.html): What happens to your files when you use an online PDF tool, the real risks, and how to choose a private option.
- [How to Choose a Free PDF Tool (Without the Catches)](https://corepdftools.com/blog/best-free-pdf-tools.html): Free PDF tools vary widely. Here's what 'free' really means and how to avoid the common traps.
- [How to Combine Scanned Pages Into One PDF](https://corepdftools.com/blog/combine-scanned-pages-into-one-pdf.html): Turn separate scanned pages or images into a single, ordered PDF document.
- [How to Compress a PDF to 100KB (Free, No Upload)](https://corepdftools.com/blog/compress-pdf-to-100kb.html): Step-by-step guide to compress any PDF to under 100KB for exam and government form uploads — entirely in your browser, no files uploaded.
- [How to Compress a PDF to 200KB Online (Free)](https://corepdftools.com/blog/compress-pdf-to-200kb.html): Reduce any PDF to under 200KB for portal and form uploads, free and in your browser. No sign-up, no file uploads.
- [Compress PDF to 300KB Online — Free Step-by-Step](https://corepdftools.com/blog/compress-pdf-to-300kb.html): Get your PDF under 300KB for uploads while keeping it readable. Free, browser-based, nothing uploaded.
- [How to Compress a PDF to 500KB (Free Online Tool)](https://corepdftools.com/blog/compress-pdf-to-500kb.html): Reduce a PDF to under 500KB for email and upload limits, free and private in your browser.
- [How to Compress a PDF Without Losing Quality](https://corepdftools.com/blog/compress-pdf-without-losing-quality.html): Understand what really happens when you compress a PDF, and how to shrink files while keeping text sharp and selectable.
- [How to Compress a PDF Without Uploading It Anywhere](https://corepdftools.com/blog/compress-pdf-without-uploading.html): Why browser-based PDF compression keeps your files private, and how to shrink a PDF without sending it to a server.
- [How to Compress a Scanned PDF (Without Making It Unreadable)](https://corepdftools.com/blog/compress-scanned-pdf.html): Scanned PDFs are large because every page is an image. Here's how to shrink them while keeping the text legible.
- [How to Convert JPG Images to a PDF (Free)](https://corepdftools.com/blog/convert-jpg-to-pdf.html): Turn one or many JPG or PNG images into a single PDF, in order, free and in your browser.
- [How to Convert a PDF to JPG Images](https://corepdftools.com/blog/convert-pdf-to-jpg.html): Turn each page of a PDF into a high-quality JPG image, free and without uploading.
- [How to Delete Pages From a PDF](https://corepdftools.com/blog/delete-pages-from-pdf.html): Remove unwanted pages — blanks, extras, or sensitive pages — from a PDF for free.
- [How to Edit a PDF on Your Phone (Free)](https://corepdftools.com/blog/edit-pdf-on-phone.html): Merge, split, compress, and sign PDFs directly from your phone's browser — no app install needed.
- [How to Extract Specific Pages From a PDF](https://corepdftools.com/blog/extract-pages-from-pdf.html): Pull out just the pages you need from a PDF into a new file, free and in your browser.
- [What Does 'Flatten a PDF' Mean?](https://corepdftools.com/blog/flatten-pdf-explained.html): A plain-language explanation of flattening a PDF, why people do it, and when you need to.
- [How Converting a PDF to Grayscale Reduces Its Size](https://corepdftools.com/blog/grayscale-pdf-to-reduce-size.html): Why grayscale shrinks scanned and image PDFs, and when it's the right move for upload limits.
- [How to Merge PDF Files Online (Free, No Upload)](https://corepdftools.com/blog/how-to-merge-pdf-files.html): Combine several PDFs into one document for free, right in your browser. Reorder pages and keep everything private.
- [How to Rearrange and Delete PDF Pages](https://corepdftools.com/blog/how-to-rearrange-pdf-pages.html): Reorder, remove, and organize the pages of a PDF visually — free and private.
- [How to Rotate Pages in a PDF (and Save It)](https://corepdftools.com/blog/how-to-rotate-pdf.html): Permanently rotate sideways or upside-down PDF pages so they display correctly everywhere.
- [How to Sign a PDF Electronically (Free)](https://corepdftools.com/blog/how-to-sign-a-pdf.html): Add your signature to a PDF by drawing it and placing it on the page — free, private, no upload.
- [How to Remove a Password From a PDF You Own](https://corepdftools.com/blog/how-to-unlock-pdf.html): Remove a known password from a PDF so it opens without one — for files you have the password to.
- [How to Combine Multiple Images Into One PDF](https://corepdftools.com/blog/images-to-single-pdf.html): Merge several photos or scans into a single, ordered PDF document — free and private.
- [How to Merge PDF Files Without Losing Quality](https://corepdftools.com/blog/merge-pdf-without-losing-quality.html): Combine multiple PDFs into one without any quality loss. Learn what causes degradation and how to avoid it.
- [How to Extract Text From a Scanned PDF (OCR)](https://corepdftools.com/blog/ocr-scanned-pdf.html): Turn a scanned, image-only PDF into searchable, copyable text using OCR — free and in your browser.
- [How to Password-Protect a PDF (Free, In Your Browser)](https://corepdftools.com/blog/password-protect-pdf.html): Add a password to a PDF so only the right people can open it — encrypted locally, never uploaded.
- [Preparing PDF Documents for Government Job Applications](https://corepdftools.com/blog/pdf-for-government-job-application.html): A practical checklist for getting your certificates, photo, and signature into the right PDF size and format for government and exam portals.
- [How to Add Page Numbers to a PDF](https://corepdftools.com/blog/pdf-page-numbers.html): Add clear page numbers to a PDF for reports, contracts, and submissions.
- [PDF Upload Rejected for Being Too Large? Here's the Fix](https://corepdftools.com/blog/pdf-upload-rejected-too-large.html): What to do when a portal rejects your PDF for exceeding the size limit — practical fixes that actually work.
- [PDF or Image: Which Should You Upload to a Form?](https://corepdftools.com/blog/pdf-vs-image-which-to-upload.html): When a portal accepts both, here's how to decide between submitting a PDF and a JPG.
- [How to Reduce PDF File Size (5 Practical Ways)](https://corepdftools.com/blog/reduce-pdf-file-size.html): Five reliable ways to make a PDF smaller, from image downsampling to removing unused content — with the trade-offs explained.
- [How to Make a PDF Small Enough to Email](https://corepdftools.com/blog/reduce-pdf-for-email.html): Get past email attachment limits by shrinking your PDF the right way.
- [How to Scan Documents to PDF (Small and Clear)](https://corepdftools.com/blog/scan-to-pdf-tips.html): Settings and habits that produce scanned PDFs that are both legible and small enough to upload.
- [How to Split a PDF Into Multiple Files](https://corepdftools.com/blog/split-pdf-into-multiple-files.html): Extract specific pages or split a PDF into separate files, free and in your browser.
- [What Is a PDF, and Why Is It Everywhere?](https://corepdftools.com/blog/what-is-a-pdf.html): A beginner-friendly explanation of what PDF files are, why they look the same everywhere, and what makes them special.
- [Why Is My PDF So Large? (And How to Fix It)](https://corepdftools.com/blog/why-is-my-pdf-so-large.html): The common reasons PDFs balloon in size — high-res images, embedded fonts, scans — and how to fix each one.

## How the tools work (technical summary)
CorePDFTools uses pdf-lib (MIT) to read and write PDF object structures for merge, split, rotate, organize, watermark, sign and protect. PDF.js renders pages to a canvas for PDF-to-JPG and for the compressor's image handling. Tesseract performs OCR. The compressor locates embedded JPEG (DCTDecode) image streams, downsamples and re-encodes them, and writes them back in place, leaving text and vector content untouched. Password protection uses a PDF encryption routine applied before saving. All of this runs in the browser; there is no server-side processing.