Why OneKit Studio is 100% free with no limits
OneKit Studio is a set of tools that run in the tab you already have open at onekitstudio.com. There is no account wall, no daily cap, and no “upgrade to merge a bigger file” prompt. If your laptop or phone can hold the document in memory, you can work on it.
That is also why it can stay free. Most converter sites rent servers, store uploads, and pay for bandwidth every time someone stitches a slide deck. Those bills turn into watermarks, email gates, and “3 files a day” limits. We never receive the file, so we never pay to store it. Chrome, Firefox, Safari, and Edge already know how to read images, allocate typed arrays, and draw to a canvas. We just point those engines at the document you picked.
You also skip the “please wait while we upload” pause. A 40 MB PDF does not travel across a network, sit in someone else’s bucket, and come back as a download. The File API reads it, pdf-lib works through the pages, and a Blob URL hands you the result. The only clock you wait on is your CPU, which on a decent laptop is often faster than a round trip to a far-away region.
Security is the same story. A server that never sees the bytes cannot leak them, mine them, or keep them after a breach. Draft contracts, scans, and unpublished work stay inside the tab. Close it and the in-memory copies go with it. That is a cleaner default than a privacy policy that promises deletion “within 24 hours.”
Unlimited use is not a slogan. We do not meter conversions because we do not host them. Refresh and start over as many times as you need.
Step-by-step guides for PDF, image, audio, video, data, and text tools
Merge PDF files
- Open PDF Tools and stay on Merger.
- Drop two or more PDFs onto the panel, or click it to browse. You should see a Ready card with the file name.
- Drag a file, or use the arrows, until the list matches the order you want.
- Hit Merge and download. Use Send output to if you want a watermark or a signature next.
Build a PDF from images
Switch to Image to PDF, add JPG or PNG files, and reorder them the same way. Each image becomes a page sized to the picture, so a poster does not get letterboxed onto a blank A4 sheet unless you resized it first. Other raster formats are drawn to a canvas and embedded as JPEG or PNG so the file stays valid.
Rotate, organize, watermark, sign, and redact
Rotate is the quick path: load one PDF, tap the page numbers, pick 90°, 180°, or 270°, and download. Unselected pages keep their current angle. Rotation adds to whatever the page already had, which is what you want when a scanner stored a landscape sheet as a rotated portrait.
Organize is the heavier editor. Thumbnails render after the file loads. Drag a page to move it, rotate a single sheet, or delete the blanks. Watermark stamps custom text on every page. Pick diagonal, center, header, footer, or a tiled pattern, then fade it with the opacity slider. Handy for drafts you are about to email.
Sign PDF lets you draw a signature on a pad or drop a PNG, then tap the page preview to place it. Size the stamp and download. Redact is for names, account numbers, and faces. Paint black boxes, then flatten. Marked pages become images so the old text cannot be highlighted or copied later.
Convert, crop, compress, strip EXIF, cut backgrounds, and make icons
Convert writes PNG, JPG, WEBP, or BMP. Leave max width and height blank to keep the original grid, or type a limit to shrink the long edge. Several files download as a ZIP. Compress encodes a live preview as you move quality from 1% to 100%. Drag the before and after slider before you save. JPG and WEBP honor the slider. PNG and BMP in the converter stay lossless.
Crop uses a drag box. Lock 1:1, 16:9, 4:5, or 9:16 for posts and stories, or leave it freehand. EXIF Privacy Stripper lists camera, GPS, and timestamp tags hiding in a JPEG. One click drops those headers. JPEG pixels stay as they were. Other formats get a clean re-encode so leftover text chunks do not ride along.
Background Remover isolates a person or product on a transparent PNG. The first run loads a model into this browser, then it is cached. Favicon Generator takes one logo and packs a ZIP with .ico plus 16, 32, 180, and 512 PNG icons, plus the HTML tags to paste in your site head. Color Picker is the practical way to grab HEX, RGB, and HSL: drop a photo and tap a pixel. On desktop Chrome you can also sample the screen.
JSON, CSV, diffs, keys, hashes, and encryption
Paste JSON or drop a .json file. An array of objects becomes rows. Nested objects flatten to dotted keys such as address.city. Download CSV, or Excel (.xlsx). Going the other way, CSV to JSON treats the first row as headers. Quoted commas stay intact.
Diff Checker sits next to those converters. Paste original and revised text side by side. Deletions show in red and additions in green, line by line. The key generator mints UUIDs, hex API keys, and passwords on this device. File Hasher writes MD5, SHA-256, and SHA-512 for any file you drop, useful when you want to confirm a download matches a published checksum. Encrypt / Decrypt locks text or a small file with a password and writes a .ok1 blob you can send over chat. The same password opens it.
Text, QR, Markdown, OCR, barcodes, and cleanup
The counter updates as you type: words, characters, characters without spaces, and sentences. Case buttons rewrite the field in place: uppercase, lowercase, Title Case, and camelCase. Base64 encode and decode use UTF-8, so non-English text round-trips instead of throwing on characters above 127.
QR Code Generator draws a square. Tint the ink and paper, then download a PNG. The scanner reads a code back from a photo. Markdown Live Editor is a split view: raw text on the left, formatted HTML on the right. OCR reads screenshots and the first page of a PDF into selectable text. Barcode Suite makes Code 128, UPC-A, and EAN-13 with color controls, and can scan a photo in Chromium. Text Cleaner strips duplicate lines, HTML tags, extra spaces, then sorts or turns a list into CSV.
Extract MP3, GIF, convert audio, trim, and shift pitch
Audio & Video uses FFmpeg in the tab. The encoder loads once, then MP4, MOV, and WEBM clips can drop their picture and save an MP3. GIF mode cuts a short loop, 10 frames a second, 480 pixels wide. Keep those clips brief so the browser does not run out of steam. Audio convert writes WAV, MP3, OGG, or AAC at 128, 192, or 320 kbps. The trimmer shows a player. Set start and end, then export the slice. Speed & Pitch is for transcribers and musicians: 0.25x to 2x, optional pitch lock, or a semitone shift, then an MP3 out. Stay near 100MB if you want it snappy. Bigger files still run on this machine. They just take longer.
Send output along, ZIP batches, and pin favorites
After a download, Send output to feeds the result into another tool so you do not re-upload. Several files can zip with optional rename rules (prefix, suffix, find and replace, numbering). Star a tool to pin it under the header. Recent activity keeps the last few outputs for a re-download in this session. Paste with Ctrl or Cmd+V. Press ? for the shortcut list.
Data privacy and security breakdown
Browsers isolate each site. JavaScript here can read files you pick, and that is it. It cannot roam the rest of your disk, peek at other tabs, or talk to a disk of ours. There is no upload endpoint. Open the Network panel while you convert something. You will not see the PDF leave the machine, because those bytes never go on the wire.
pdf-lib, Cropper.js, Diff.js, QRCode.js, PapaParse, SheetJS, FFmpeg, Tesseract, JSZip, and the background-removal model all run in this page. WebAssembly still has the same origin privileges as the script. It cannot open sockets your page could not open. Canvas encoding for images is origin-bound too. Object URLs created for downloads get revoked after the save prompt so large files do not hang around.
That local sandbox is why people handling GDPR, HIPAA, or internal data rules can use these tools without sending records to a third-party converter. GDPR’s minimization idea is met by never collecting the file. HIPAA transmission rules are not triggered by a process that never transmits electronic protected health information. Follow your own rules about where a browser tab may run. OneKit does not become a business associate by hosting the document, because it does not host the document.
Ads on the public site are a separate channel from file processing. If Google AdSense is present, it may set third-party cookies (including the DoubleClick / DART cookie) to serve and measure ads. Those cookies do not receive your PDFs, images, or pasted JSON. You can opt out of personalized ads in Google’s Ad Settings. Block cookies if you want. The converters still run.
We do not create accounts, so there is no password list to steal. Theme preference lives in localStorage on your device. The contact form confirms in the browser and can open your own mail client. It does not post messages to our servers. If you need a paper trail for a compliance review, treat the page itself as the audit: every transform is in the scripts your browser already downloaded.