JFDI Blog

Tag: privacy

  • Which online file tools upload your files? We checked six

    All six popular online file tools we checked upload your file to their servers to process it, and say so in their own documentation: Smallpdf, iLovePDF, Adobe Acrobat’s online tools, CloudConvert, Zamzar and remove.bg. They say they delete files after anything from about an hour to seven days. That’s not sinister, it’s how most of these services work, but it’s worth knowing before you drop in a payslip, a passport scan or a client’s contract. Tools that run in your browser, like JFDI, don’t upload anything.

    Use tools that don’t upload

    What each tool says

    We read each company’s own help, security or privacy pages in October 2026. Policies change, so follow the links for the current wording.

    ToolUploads your file?What it says about keeping itSource
    SmallpdfYes, to servers in IrelandFree tool usage: “Files deleted after 1 hour”Smallpdf
    iLovePDFYes“Completely deleted within 2 hours of upload”, or straight away with a Delete it now buttoniLovePDF
    Adobe Acrobat online toolsYes: “Acrobat online services upload your files to Adobe cloud storage”Signed in: kept in your account. Not signed in: deleted after an unspecified short periodAdobe
    CloudConvertYes, to servers in Germany, or the US for US users“Automatically deleted after 24 hours at the latest”, or straight away with the delete buttonCloudConvert
    ZamzarYesFor people without an account, kept “for no longer than 7 days following receipt”Zamzar
    remove.bgYesDeleted “at the latest about one hour after the upload”remove.bg

    All six are served over encrypted (HTTPS) connections, and several describe further security measures. None of this suggests they misuse files. The point is simply that, for a while, your file exists on a computer you don’t control.

    Why it can matter

    For a restaurant menu or a holiday photo, it probably doesn’t. It’s worth thinking twice when:

    • The file is about someone else. Customer lists, patient letters, HR documents and client contracts often come with legal duties. Many employers’ policies forbid putting them into unapproved online services.
    • The file is about you, in detail. Passports, bank statements, payslips and tax returns are exactly what identity thieves want.
    • The file is confidential before publication: results, a manuscript, a bid, an unannounced product.

    Any company storing files, even briefly, can suffer a data breach, a mistake or a legal demand. A file that never leaves your device can’t be caught up in any of those.

    How browser-only tools are different

    A browser-only tool sends you the program instead of asking you for the file. The page loads code into your browser, and your browser does the converting, compressing or editing on your own computer. When you click Download, the result is saved from your browser’s memory straight to your device. Our explainer on how browser-only tools work goes into the technology.

    That’s how every JFDI tool works: the PDF toolkit, file converter, image editor (including background removal), chart maker, map maker and QR code maker.

    Check any tool yourself in two minutes

    You don’t have to trust anyone’s privacy page, including ours. Your browser can show you every request a page makes.

    1. Open the tool in Chrome, Edge or Firefox.
    2. Press F12 (or right-click the page and choose Inspect) and open the Network tab.
    3. Tick Preserve log (Chrome and Edge) or Persist Logs (Firefox, in the settings cog), and clear the list with the 🚫 button.
    4. Use the tool as normal: add a file, convert it, download the result.
    5. Look at the list. Sort by Size or look for requests with the method POST or PUT. An upload shows up as a request whose size is roughly the size of your file, sent to the tool’s server.

    On a browser-only tool you’ll see the page fetch its own code (and, for some tools, a one-off download such as a font or an AI model), but nothing sent out that’s as big as your file. On an upload-based tool, you’ll see your file go.

    JFDI File Converter does not upload your files away from your device. All of the work is performed locally, in private.
    Some online file converter tools upload your files to their server - compromising your privacy.

    Do browser tools have downsides?

    Yes, a few:

    • Your device does the work, so very large files are faster on a computer than an old phone.
    • Nothing is saved for you. Close the tab and your work is gone unless you’ve downloaded it.
    • Some jobs need a server, such as OCR on scanned documents or converting formats browsers can’t read. Those services aren’t wrong to upload; just choose them deliberately.

    Related

  • How to redact a PDF properly (a black box isn’t enough)

    To redact a PDF properly, the hidden words have to be removed from the file, not just covered. A black rectangle, a black highlight or a white box drawn on top hides text from view, but the text is still there underneath, and anyone can select it, copy it and paste it somewhere else. Use a real redaction tool, then check the result before you send it.

    Redact a PDF

    The black box mistake keeps happening

    This isn’t a beginner’s error. It has caught out lawyers, government departments and newspapers for years:

    • January 2019: lawyers for Paul Manafort filed a document in his case with black bars over sensitive passages. A Guardian reporter found the text could be copied and pasted into a new document, revealing details about his contacts with Konstantin Kilimnik (Columbia Journalism Review).
    • 2014: redactions in a leaked CIA presentation published by The New York Times could be bypassed by highlighting and copying, exposing an NSA agent’s name.
    • 2011: a federal judge’s opinion in Apple v. Samsung had redacted passages that could be copied into a text document.
    • A 2011 study estimated that “thousands, and probably tens of thousands” of documents in the US federal courts’ PACER system had redaction failures.

    The last three are from the American Bar Association’s round-up of embarrassing redaction failures.

    Why covering doesn’t work

    A PDF isn’t a picture of a page. It’s a list of instructions: put these words here in this font, draw this shape there, place this image. When you draw a black box, you add one more instruction, draw a black rectangle, on top. The instruction that draws the words is untouched, so:

    • Copy and paste pulls the text from under the box.
    • Search finds it.
    • Screen readers read it aloud.
    • Text extraction by any program, including search engines, sees it.

    The same goes for black highlighting in Word before saving as PDF, and for white-out boxes.

    What proper redaction does

    Real redaction removes the content under the box from the file. In the JFDI PDF toolkit, the Redact tool works like this:

    1. Open the PDF in the toolkit and go to Edit & sign.
    2. Choose Redact (shortcut X) and drag over every name, number or passage that must go.
    3. Download. Each page with a redaction is rebuilt as a 200 dpi image with the black boxes burned in, so the hidden words no longer exist anywhere in the file.

    The trade-off: the rest of a redacted page can no longer be selected or searched, because the page is now a picture. Pages without redactions stay as normal text. Page numbers and watermarks are added afterwards, so they stay sharp.

    Nothing is uploaded at any point. The PDF is opened and rebuilt inside your browser, which is the point when the document is confidential.

    Don’t forget the hidden information

    Visible text isn’t the only thing that leaks. PDFs can carry:

    • Document details: the author’s name, the software used, creation and editing dates.
    • Editing history: some programs save changes by adding to the end of the file, so earlier versions of a page can still be inside.
    • Attachments, scripts and form data.
    • Text under scans: a scanned page that’s been through OCR has an invisible text layer behind the image.

    In the toolkit’s Finish tab, tick Remove hidden information before downloading. It strips the author, software, dates, embedded metadata, scripts, attachments and editing history. And check the file name: “Smith-v-Jones-settlement-£2.4m.pdf” can give away what the redactions hide.

    White-out or redact?

    White-outRedact
    Looks likeA white (or coloured) boxA black box
    The hidden wordsStill in the file. Anyone can copy them.Removed for good
    Rest of the pageUnchangedTurned into an image
    Use it forTidying up, hiding a typo, making space for new textNames, addresses, account numbers, anything confidential

    The toolkit’s Change existing text tool also covers the original words rather than removing them, so never use it to remove private information.

    Check before you send: five tests

    1. Select all and copy (Ctrl+A, Ctrl+C) on each redacted page, then paste into a text editor. Nothing hidden should appear.
    2. Search the PDF for a redacted word, such as a surname.
    3. Open it in a different PDF reader: your browser’s built-in viewer and one other.
    4. Check the document properties (File › Properties in most readers) for the author and title.
    5. Read the file name.

    Common questions

    Can a redaction be undone?

    Not when the content has been removed, as above. A drawn box can be “undone” by anyone with a PDF editor, by simply deleting the box.

    Is redacting a scanned document different?

    A scan is already a picture, so a black box burned into the image hides it. But scans often have an invisible OCR text layer; a real redaction tool removes that too, which is why the toolkit rebuilds the page.

    Does Adobe Acrobat do this properly?

    Yes, when you use its Redact tool and apply the redactions; drawing a black shape with its comment tools doesn’t. The same check above works for any tool.

    Related

  • How browser-only tools work, in plain English

    A browser-only tool sends you the program instead of asking for your file. When you open the page, your browser downloads the tool’s code; when you add a file, the browser reads it from your disk and processes it on your own computer; when you click Download, the result goes straight from your browser’s memory to your device. The website’s server never receives the file, so it can’t keep, leak or look at it.

    Try the tools

    Two ways a file tool can work

    Upload-based toolBrowser-only tool
    Where the work happensThe company’s serverYour computer or phone
    Your file travelsTo the server and backNowhere
    Speed depends onYour upload speed and their queueYour device
    Size limitsOften capped on free plansYour device’s memory
    Works offline after loadingNoOften, for much of the work
    Can save your work for youYes, if you have an accountNo: you download it

    Most well-known online file tools are upload-based; we looked at what six of them say about it in Which online file tools upload your files?

    What makes it possible

    Ten years ago, a web page couldn’t realistically edit a PDF or convert a video. Several things changed that:

    • WebAssembly. A way to run fast, compiled programs inside a web page, at close to the speed of a desktop app. It became an official W3C web standard on 5 December 2019, described as “a virtual instruction set architecture that enables high-performance applications on the Web” (W3C). It lets existing software, written in languages like C, C++ and Rust, run in the browser.
    • Access to your device’s media hardware. The WebCodecs interface lets a page use the same chips your device uses to record and play video, so converting a video in a browser can be as fast as in a desktop app.
    • Access to your graphics card. WebGPU lets a page run heavy maths, such as an AI model, on the graphics processor.
    • Background threads. Web Workers let a page do heavy work without freezing, so you can keep using it while a batch of 300 photos processes.
    • Reading and saving files locally. Browsers can read a file you choose and save a result, all without a server in between. Chrome and Edge can even write results straight into a folder you pick.

    How each JFDI tool uses them

    ToolWhat runs in your browser
    PDF toolkitMozilla’s PDF.js draws the pages; pdf-lib rebuilds the file with your changes
    File converterSheetJS for spreadsheets; Mediabunny with WebCodecs for video and audio
    Image editorA HEIC decoder compiled to WebAssembly; the IS-Net background-removal model on WebGPU, or WebAssembly when there’s no usable graphics card
    Chart maker and map makerThe d3 drawing library, plus boundary files served from this site
    QR code makerA QR encoder written in plain JavaScript

    All of these are open-source libraries, credited in our licences file.

    What still gets downloaded

    “Nothing is uploaded” doesn’t mean “nothing is downloaded”. Your browser fetches:

    • The tool’s code, when you open the page.
    • Extra pieces when they’re needed: the PDF engines in the background after the PDF toolkit opens, the 44 MB background-removal model the first time you use it, map boundaries for the US or UK when you make those maps. Your browser keeps them, so later visits are quick.
    • The font for the pages, from Google Fonts. Like any website, Google can see your IP address when your browser fetches it. Our privacy page explains this.

    None of these requests contain your files.

    How to check for yourself

    Open the browser’s developer tools (F12), choose the Network tab, and use the tool. You’ll see every request the page makes. An upload shows up as an outgoing request about the size of your file; on a browser-only tool, there isn’t one. The steps are in Which online file tools upload your files?

    The trade-offs

    • Your device does the work, so a huge video converts faster on a laptop than an old phone.
    • Nothing is saved for you. That’s the privacy, but it also means closing the tab loses unsaved work. Download as you go.
    • Some jobs still need a server, such as recognising text in scanned documents (OCR) or reading formats browsers can’t, like old Word .doc files.

    Related

  • How to edit a PDF without uploading it

    To edit a PDF without uploading it, use an editor that runs inside your browser rather than on a company’s server. The JFDI PDF toolkit opens the file on your device, lets you add and change text, sign, fill in forms, reorder pages and redact, then rebuilds the PDF locally when you download. The file never leaves your computer, and there’s no account.

    Edit a PDF

    Why it matters

    The PDFs people edit are often the most sensitive files they have: contracts, payslips, tax forms, medical letters, ID scans. Most popular online editors upload them to process them. Their privacy pages say so, and say how long the files are kept, typically from one hour to a day. That may be fine for a menu; it’s worth avoiding for a tenancy agreement. We looked at what six well-known tools say in Which online file tools upload your files?

    What you can do

    TaskHow
    Add text anywhereAdd text (T): click and type
    Change a line of existing textChange existing text (E): click the line and retype
    SignSignature (S): draw, type or upload your signature
    Fill in a formClick the blue-tinted boxes with Select (V)
    Tick boxes on a form with no fieldsTick and Cross tools
    Highlight, draw, add shapes and arrowsHighlight (H), Draw (D), Rectangle (R), Arrow (A)
    Add a picture or logoImage
    Hide something for goodRedact (X)
    Reorder, rotate, delete or duplicate pagesPages tab
    Merge several PDFsOpen them together; their pages appear in one list
    Add page numbers, a header, footer or watermarkFinish tab
    Make the file smaller, or add a passwordFinish tab

    Everything can be undone with Ctrl+Z (⌘+Z on a Mac).

    Step by step: changing a line of text

    1. Open the PDF toolkit and drop your PDF on the page.
    2. Go to Edit & sign and choose Change existing text (shortcut E). Lines of the PDF’s own text light up as you point at them.
    3. Click the line you want to change and type the new words. The toolkit matches the position, size, colour and style (sans-serif, serif or monospaced) as closely as it can.
    4. Download PDF from the top right.

    What you can’t do (with any editor, mostly)

    PDFs aren’t word-processor documents, and it helps to know the limits:

    • Changed text is laid over the original. The tool covers the old line with a box in the background colour and puts the new text on top. That’s how most PDF editors work behind the scenes, but it means the original words are still in the file. Never use it to remove private information: use Redact.
    • Fonts are matched, not copied. New text uses Helvetica, Times or Courier, the fonts every PDF reader has. Unless the original used one of those, look closely and pick the nearest.
    • Paragraphs don’t reflow. Change a line and the next line doesn’t move up or down. For big rewrites, go back to the original Word or Pages file if you have it.
    • Scanned pages are pictures. There’s no text to change. Use White-out to cover the old words and Add text for the new ones.

    How to check nothing is uploaded

    You don’t have to take our word for it. In Chrome, Edge or Firefox, press F12 to open the developer tools and choose the Network tab. Open and edit your PDF, then download it. You’ll see the page’s own files load, and nothing sent out containing your document. Our guide to checking whether a website uploads your file shows what to look for.

    Common questions

    Is there a file size or page limit?

    No set limit. Everything happens on your device, so very large files depend on its memory. Computers cope with big files much better than phones.

    Does it work on a phone or tablet?

    Yes. The tools scroll along the top, and you can sign with your finger.

    Is my work saved if I close the tab?

    No, because nothing is stored anywhere. Your browser asks you to confirm if you try to close the tab with changes you haven’t downloaded.

    Related

  • Free alternatives to Smallpdf, iLovePDF and CloudConvert that don’t upload files

    If you want a free alternative to Smallpdf, iLovePDF or CloudConvert that doesn’t upload your files, use tools that run inside your browser. JFDI covers the most common jobs (merging, compressing, editing, signing and redacting PDFs; converting documents, spreadsheets, video, audio and images) with no account, no watermark and no daily limits, and your files never leave your device. It doesn’t do everything the big services do, and this post is honest about the gaps.

    See the tools

    The big three, fairly

    Smallpdf, iLovePDF and CloudConvert are popular for good reasons: they’re quick, polished and handle a huge range of formats. All three process files on their servers, and all three are open about it. By their own documentation, Smallpdf deletes free users’ files after 1 hour, iLovePDF within 2 hours, and CloudConvert within 24 hours at the latest, with delete buttons for immediate removal on the latter two. We compared six services’ policies in Which online file tools upload your files?

    For most files that’s fine. For contracts, payslips, ID documents, client data or anything your employer says shouldn’t go into unapproved services, a tool that never receives the file is simpler.

    Task by task

    TaskUpload-based servicesJFDI, in your browser
    Merge, split, reorder, rotate PDFsYesYes: PDF toolkit
    Compress a PDFYesYes, with four levels
    Edit text, add text, signYesYes
    Fill in PDF formsYesYes
    RedactVaries by service and planYes, removing the text for good (how)
    Add or remove a PDF passwordYesYes (AES-256)
    Word, EPUB, Markdown, HTML to PDFYesYes: file converter
    PDF to WordYes, often with layout keptText and headings only; columns, tables and pictures aren’t kept
    OCR (text from scans)Yes, often paidNo
    PowerPoint, old Word .docYesNo: browsers can’t read these
    Spreadsheets: CSV, Excel, JSON, XML, SQLYesYes, keeping leading zeros and dates (why that matters)
    Video: MOV, MP4, MKV, WebM, GIFYes, usually with size caps on free plansYes, no size limit (MOV to MP4)
    AVI, WMVYesNo
    Audio and subtitlesYesYes
    Images: HEIC, WebP, AVIF, compress, resizeYesYes: image editor
    Background removalSeparate servicesYes, on your device
    Save files in the cloud, share links, team accountsYes, with an accountNo
    API for developersCloudConvert and othersNo

    Where the upload-based services are better

    • OCR. Turning a scanned document into searchable, editable text needs heavy processing that’s usually done on a server.
    • PDF to Word with the layout intact. Rebuilding columns and tables from a PDF is hard; the best results come from server-side engines.
    • Old and proprietary formats, such as .doc, PowerPoint, AVI and WMV.
    • Workflows: cloud storage, sending documents for other people to sign, team plans and integrations.

    If you need those, use those services, ideally with files that aren’t sensitive.

    Where the browser-only approach is better

    • Privacy by design. There’s no upload to trust or check, and no retention period to read about.
    • No size limits. The limit is your device’s memory, so large videos and long PDFs work.
    • No account, no daily limit, no watermark.
    • Speed for big files. Nothing has to travel across the internet and back.
    • It keeps working if we disappear: QR codes contain your link directly, embeds contain your data, and downloads are ordinary files.

    Other privacy-friendly options

    Browser-only isn’t the only way to keep files local. Desktop apps do too: LibreOffice for documents, HandBrake for video, and the PDF editors built into Preview on a Mac. They’re good choices if you’re on your own computer and willing to install software. Browser tools suit work computers where you can’t install things, Chromebooks, and quick jobs on any device.

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