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UploadFree

About UploadFree

UploadFree offers free tools for everyday file tasks. The tools run inside your web browser, so your files are processed on your own device instead of being uploaded to a server.

Available tools

  • Image Compressor — Reduce the file size of JPEG, PNG and WebP images in your browser, with optional resizing and batch ZIP download.
  • Image Converter — Convert JPEG, PNG and WebP images to another of these formats in your browser, one at a time or in a batch.
  • HEIC to JPG — Convert HEIC and HEIF still photos, such as iPhone photos, to JPG in your browser, in a batch with a ZIP download.
  • Image Resizer — Resize JPEG, PNG and WebP images to an exact size, to fit within a box, or by percentage, in your browser.
  • Image Cropper — Crop a JPEG, PNG or WebP image to any area or aspect ratio, with exact pixel values, in your browser.
  • Compress to Size — Get JPEG, PNG and WebP images under a file-size limit such as 100 KB or 1 MB, adjusting quality and size in your browser.
  • Watermark Images — Add a text or logo watermark to JPEG, PNG and WebP images, one position or repeated, in a batch in your browser.
  • Image Metadata Viewer & Remover — See the EXIF, GPS location, camera and other metadata in JPEG photos and remove it, in your browser.
  • Merge PDF — Combine several PDF files into one, in the order you choose, without uploading them.
  • Split PDF — Extract selected pages, save every page as its own PDF, or split by custom ranges, without uploading the file.
  • Organize PDF — Reorder, rotate and remove pages of a PDF with page previews, with undo, in your browser.
  • Images to PDF — Combine JPEG, PNG and WebP images into one PDF, one image per page, on A4, Letter or image-sized pages, in your browser.
  • PDF to Images — Turn all or selected pages of a PDF into JPG or PNG images at 72, 150 or 300 DPI, in your browser.
  • Compress PDF — Make scanned and image-heavy PDFs smaller by rebuilding the pages as compressed images, in your browser. The result is image-only.
  • Watermark PDF — Add a text watermark such as DRAFT or CONFIDENTIAL to all or selected PDF pages, as real text, in your browser.
  • Add Page Numbers — Add page numbers to all or selected PDF pages, as 1, Page 1 or Page 1 of N, in six positions, as real text in your browser.
  • Text Compare — Compare two texts line by line with changed words highlighted, side by side or unified, optionally ignoring case and whitespace, in your browser.
  • Word & Character Counter — Count words, characters with and without spaces, sentences, paragraphs and lines as you type, with an optional character goal, in your browser.
  • Text Cleaner — Clean plain text with options you choose: trim and collapse spaces, convert tabs, remove blank or duplicate lines, and set LF or CRLF line endings, in your browser.
  • Case Converter — Convert text to lowercase, UPPERCASE, Sentence case, Title Case or Toggle Case, or to camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE, in your browser.
  • JSON Formatter & Validator — Check JSON for errors with line and column, then format it with 2 spaces, 4 spaces or tabs, or minify it, keeping numbers and duplicate keys exactly as written, in your browser.
  • CSV ↔ JSON Converter — Convert CSV to a JSON array of objects with every value kept as text, or an array of flat JSON objects to CSV with spreadsheet formula protection, using comma, semicolon or tab delimiters, in your browser.
  • Base64 Encoder & Decoder — Encode text or a file as Base64 or Base64URL, or decode Base64 back to text or a downloadable file, in your browser.
  • URL Encoder & Decoder — Percent-encode or decode a URL component or a form value as UTF-8, with clear errors for malformed escapes, in your browser.
  • ZIP Extractor — Open a ZIP file in your browser, browse its folders, then download single files, selected files as a new ZIP, or everything, without uploading it.
  • Create ZIP — Put several files or a folder into one ZIP with Store, Balanced or Maximum compression, keeping every byte of each file, in your browser.
  • GZIP Compress & Extract — Compress one file into a .gz with a speed preset, or decompress a .gz file with its checksum verified, in your browser.
  • Audio Converter — Convert an MP3, WAV, M4A, Ogg or FLAC file to MP3, WAV or FLAC in your browser, with the real output settings shown and nothing uploaded.
  • Audio Trimmer — Keep one section of an audio file: set start and end times or drag handles on the waveform, preview the section, and save it as MP3 or WAV, in your browser.
  • Audio Volume Changer — Make an audio file louder or quieter by a set number of decibels, with a clipping warning and an optional limit to the available headroom, saved as MP3 or WAV in your browser.

How it works

The website is a set of static pages. When you open a tool, your browser downloads the code for that tool and runs it locally. For images, UploadFree uses the image decoders built into your browser (the Canvas and createImageBitmap APIs). Smaller PNG files can also be made by the tool’s own code, which reduces the number of colors in the image, also on your device. Heavy work runs in a background Web Worker where your browser supports one, so the page stays responsive, and files are processed a few at a time to keep memory use predictable.

JPEG, WebP and PNG files are encoded with MozJPEG, libwebp and OxiPNG, packaged for the web by the jSquash project as WebAssembly. They run on your device, are served from this site, and are loaded only when an image is saved in that format. If they can’t load, your browser’s built-in encoder is used instead.

PDFs are merged and split with the open-source pdf-lib library, which runs in a background Web Worker on your device. Files are read one at a time, and every PDF the tools create is a new document built from the original pages.

HEIC and HEIF photos are decoded with libheif-js, an open-source WebAssembly build of libheif and libde265, unless your browser can decode HEIC itself. It is loaded from this site, as a separate file, only when you convert a HEIC photo.

ZIP and GZIP files are read and written with the open-source fflate library (MIT licence), in a background Web Worker on your device. The ZIP file list is read from the archive’s own index without unpacking it, files are unpacked and checked one at a time, and the archive tools support Store and Deflate ZIP entries without passwords, single-file GZIP (including joined members) and no other archive formats.

Audio is decoded by your browser’s own audio decoders. WAV files are written directly; MP3 and FLAC files are written with the open-source Mediabunny library (MPL-2.0 licence) and its encoder extensions, which contain the LAME MP3 encoder (LGPL licence) and the libFLAC encoder (BSD licence) compiled to WebAssembly. The encoders run in a background Web Worker on your device and are loaded from this site only when you convert, trim or change the volume of audio. The audio tools open one MP3, WAV, M4A (AAC-LC), Ogg Vorbis or Opus, or FLAC file at a time, mono or stereo, and save MP3, WAV or FLAC.

Because processing depends on your browser, results can differ slightly between browsers. Some options are not available everywhere, for example in very old browsers without WebAssembly, and the tool will tell you when an option is not available rather than producing a different format.

What it does not do

  • It does not upload your files or keep copies of them.
  • It does not work without an internet connection on first visit; the pages and tool code must load first.
  • It does not keep image metadata such as camera details or GPS location in the files it creates. Photos are rotated according to their orientation tag and colors are converted to the standard sRGB color space (a HEIC photo’s embedded color profile is attached to its JPEG instead, where the photo has one).
  • It does not process animated images yet, and it tells you so instead of silently flattening them.
  • It does not open password-protected or encrypted PDFs, and it does not remove or bypass passwords.

Open-source software

The HEIC decoder, libheif-js (version 1.23.5, containing libheif and libde265), is free software licensed under the GNU Lesser General Public License, version 3. Its source code is available at the links above. It is used unmodified and is served as a separate file, so it can be replaced with another build.

The image encoders are packaged by jSquash (licensed under the Apache License 2.0): @jsquash/jpeg 1.6.0 containing MozJPEG (IJG and BSD-style licenses), @jsquash/webp 1.5.0 containing libwebp (BSD license), and @jsquash/oxipng 2.3.0 containing OxiPNG (MIT license). They are used unmodified and are served as separate files.

Text Compare uses jsdiff (diff 9.0.0), licensed under the BSD 3-Clause License.

The JSON Formatter & Validator uses jsonc-parser (jsonc-parser 3.3.1, by Microsoft), licensed under the MIT License. It reads where each value sits in your JSON; it does not run the text as code.

The CSV ↔ JSON Converter uses csv-parse (csv-parse 7.0.3, by Adaltas), licensed under the MIT License. It reads CSV text in your browser; it does not run it as code.

Cost

The tools are free to use. In the future the site may be supported by advertising, which would be kept separate from the tools themselves. See the privacy policy for what that would mean.