Software Alternatives, Accelerators & Startups

FreeFileSync VS KeptPDF

Compare FreeFileSync VS KeptPDF and see what are their differences

Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

FreeFileSync logo FreeFileSync

FreeFileSync is a free open source data backup software that helps you synchronize files and folders on Windows, Linux and macOS.

KeptPDF logo KeptPDF

Redact, edit, OCR, and sign PDFs entirely in your browser. The file never leaves your device. Free, no account needed.
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  • FreeFileSync Landing page
    Landing page //
    2023-09-24
  • KeptPDF Landing page
    Landing page //
    2026-08-22

KeptPDF is a PDF toolkit that runs entirely in your browser. Nothing uploads: every tool runs on your own device, so the document never touches a server.

What it does:

  • Redaction that auto-detects names, SSNs, phone numbers, addresses, and dates, then removes the underlying text instead of drawing a box over it. Every redacted file gets an audit certificate that anyone can verify.
  • OCR that makes scanned PDFs searchable, with on-device processing.
  • Sign, annotate, compare, organize, split, merge, compress, convert, watermark, Bates numbering, exhibit stamps, and more. About 25 tools in total.
  • A command line version runs the same redaction engine on your own servers for bulk work: scanning bureaus, litigation support teams, and records departments process thousands of PDFs in one pass.

Who it is for: law firms, accounting practices, clinics, and anyone who shares documents they cannot afford to leak.

The core tools are free with no sign-up. Works offline as an installable app.

KeptPDF

$ Details
freemium $29 / Monthly (Pro, 1 user)
Release Date
2026 May
Startup details
Country
United States
State
Tennessee
Founder(s)
John Whitworth

FreeFileSync features and specs

  • Free and Open Source
    FreeFileSync is freely available without any cost and its source code can be inspected, modified, and enhanced by anyone.
  • Cross-Platform
    The software is available for multiple operating systems including Windows, macOS, and Linux, making it versatile for users across different platforms.
  • User-Friendly Interface
    The application features an intuitive, easy-to-use graphical interface that simplifies the process of setting up and running backups and syncs.
  • Advanced Sync Options
    FreeFileSync offers advanced options like real-time sync, versioning, and mirror sync, giving users flexibility in how they manage their files.
  • High Performance
    The software is optimized for speed and efficiency, enabling quick synchronization and backup processes even for large directories.
  • Robust Error Handling
    FreeFileSync has robust error handling and recovery features, ensuring data integrity and reliability during file operations.

Possible disadvantages of FreeFileSync

  • Limited Cloud Integration
    FreeFileSync offers limited integration with cloud storage services, which may not be sufficient for users heavily reliant on cloud platforms.
  • Potentially Complex for Novices
    While the interface is user-friendly, some of the advanced options and settings may be overwhelming for new or inexperienced users.
  • Donation Requests
    The software occasionally prompts users to donate, which some may find intrusive or annoying despite being free to use.
  • No Automated Scheduling in Free Version
    Automated scheduling is not available in the free version, requiring users to manually trigger synchronization or purchase the donation edition for this feature.
  • Community Support
    Being open-source, the primary support channel is community forums, which may not offer the same level of assistance as dedicated customer service.

KeptPDF features and specs

  • Simple PDF Editing
    KeptPDF offers straightforward tools for editing, merging, splitting, and converting PDF files, making it accessible for users who need quick document management without a steep learning curve.
  • Web-Based Accessibility
    Being a web-based tool, KeptPDF can be accessed from any device with an internet connection, eliminating the need for software installation and allowing use across different operating systems.
  • Multiple File Format Support
    The platform supports conversion between PDF and various other file formats, offering flexibility for users who work with documents in different formats.
  • No Installation Required
    Since it operates in a browser, users can save storage space on their devices and avoid compatibility issues that sometimes arise with desktop software installations.
  • Quick Processing
    KeptPDF is designed to process PDF tasks efficiently, allowing users to complete common document tasks like compression or conversion in a relatively short amount of time.

Analysis of FreeFileSync

Overall verdict

  • Overall, FreeFileSync is a highly regarded file synchronization and backup solution. Its combination of powerful features, user-friendly interface, and low cost (free) makes it a popular choice for individuals and small businesses looking to manage their file synchronization needs.

Why this product is good

  • FreeFileSync is considered good by many users because of its robust feature set, ease of use, and the fact that it is open source. It offers features such as real-time synchronization, support for multiple platforms, and the ability to handle large files and numerous files efficiently, which makes it a versatile tool for personal and professional use.

Recommended for

    FreeFileSync is recommended for users who need a reliable and efficient way to sync files across devices or create consistent backups. It is ideal for both casual users who need a straightforward backup solution and more technical users who require advanced features and customization.

FreeFileSync videos

Simple, Fast, Automated File Backup [FREE] | 2020 [FreeFileSync]

More videos:

  • Review - FreeFileSync: Tips and Tricks
  • Review - FreeFileSync: RealTimeSync
  • Review - FreeFileSync: Folder Comparison and Synchronization

KeptPDF videos

No KeptPDF videos yet. You could help us improve this page by suggesting one.

Add video

Category Popularity

0-100% (relative to FreeFileSync and KeptPDF)
File Sharing And Backup
100 100%
0% 0
PDF
0 0%
100% 100
Backup And Disaster Recovery
PDF Readers And Editors
0 0%
100% 100

Questions & Answers

As answered by people managing FreeFileSync and KeptPDF.

What makes your product unique?

KeptPDF's answer:

KeptPDF runs entirely in your browser. Your file, and the text inside it, never leaves your device. Not to an AI, not even to us. You can open your browser's network tab and watch: the document bytes never go out.

Most online PDF tools upload your file to a server first, and some "AI redaction" services quietly send your document text to a third-party model. That is the exact risk people are trying to avoid when they redact something.

KeptPDF also does true redaction. The text is removed from the file, not covered with a black box you can copy out later. Every redaction produces a verification certificate you can share with the file.

Why should a person choose your product over its competitors?

KeptPDF's answer:

Three reasons.

Privacy you can verify, not just a promise. Processing happens locally in the browser, so there is no upload step to trust. We do send anonymous usage counts for quota, and we say so plainly, but never your document.

Real redaction with proof. Removed text is permanently gone, and you get a certificate showing the file was checked for leftover extractable text. Automated detection cannot catch everything, so a final human review is still your job, and the tool says that too.

It works on a phone. Most PDF suites assume a desktop. KeptPDF was built and used on a phone first, so redacting a document while you are standing in a hallway actually works.

How would you describe the primary audience of your product?

KeptPDF's answer:

Anyone who has to hand a document to someone else and needs the sensitive parts gone first.

In practice that is solo attorneys and small law firms, accountants and tax preparers, healthcare and records staff handling requests, HR teams, and individuals dealing with their own medical, legal, or financial paperwork.

The common thread is not an industry. It is a person who cannot upload a confidential file to a random website, and who does not have an enterprise IT budget to solve it.

What's the story behind your product?

KeptPDF's answer:

A family member got seriously ill. We spent most days at the hospital, and straight answers were hard to come by, so we leaned on AI tools to make sense of the records, notes, and lab results.

But you cannot paste a medical record into an AI chat. You have to strip the names, the ID numbers, the diagnoses first. And almost every tool we found either wanted to upload the whole file to a server, or "auto-redacted" by sending the document text to an online AI. That was the exact thing we were trying to avoid.

Most of this was happening on a phone, at a bedside. So I built the tool I needed: redaction that runs on the device, works on mobile, and never sends the file anywhere. That turned into KeptPDF, which is now a full PDF suite with over 20 tools, all local-first.

Which are the primary technologies used for building your product?

KeptPDF's answer:

The app is plain JavaScript with no front-end framework, which keeps it fast and keeps the code auditable.

PDF work happens in the browser using pdf.js for rendering and pdf-lib for writing. Text recognition uses Tesseract running as WebAssembly. Password and encryption handling uses a WebAssembly build of qpdf. It is a Progressive Web App, so it installs and works offline.

The thin server side is Node on Vercel, with Postgres for accounts, Stripe for billing, and Resend for email. None of those ever see a document.

Who are some of the biggest customers of your product?

KeptPDF's answer:

KeptPDF is early and independent, and we do not publish customer names. The product is privacy-first by design: we never see your documents, and we do not track who our users are or what they work on. Publishing a client list would sit badly next to that.

The user base today is mostly solo attorneys, small firms, accountants, and individuals handling their own records.

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare FreeFileSync and KeptPDF

FreeFileSync Reviews

15 Best Rclone Alternatives 2022
As a result, FreeFileSync helps speed up backup procedures by comparing source and target folders and just copying what is needed rather than copying everything. Additional synchronization options are available via the command line just like with rclone.
The 5 Best File Syncing Apps
FreeFileSync is useful for individuals and businesses for comparing multiple folders and synchronizing folders. It provides a robust backup solution. Choose to sync folders in real time, sync on a schedule, or run the sync program at startup.
Review of the File Synchronization Tools
FreeFileSync is a folder comparison and synchronization software, which can create and manage backup copies of all important files. FreeFileSync does not need to copy every file every time but determines the difference between the source folder and the destination folder and transfers only the minimum amount of data required. FreeFileSync is open source software, which can...
8 best Windows 10 file sync software
User feedback: โ€œAfter wasting $40+ dollars on a competitorโ€™s product, I tried out Freefilesync. FreefileSync was able to compare hundreds of thousands of files [โ€ฆ] in 10 minutes, which was taking the competitorโ€™s product over 3 hours.โ€
12 Free File and Folder Synchronization Tools for windows
Enhanced for maximum performance, FreeFileSync is an open source tool that assists you to sync files and folders for different operating systems like, Windows, Mac OS X and Linux. It comes with a simplified interface and offers an optimized usability. Using this tool you can compare data by date, size or content. You simply need to drag and drop the folders you want to...
Source: thegeekpage.com

KeptPDF Reviews

We have no reviews of KeptPDF yet.
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Social recommendations and mentions

Based on our record, FreeFileSync seems to be more popular. It has been mentiond 205 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

FreeFileSync mentions (205)

  • Ask HN: What software subscriptions are worth paying for?
    JetBrains IDEs: https://www.jetbrains.com/ (free alternative: Visual Studio Code plus DB tools like DBeaver, or even their community versions) MobaXTerm: https://mobaxterm.mobatek.net/ (free alternative: mRemoteNG, PuTTY) GitKraken: https://gitkraken.dev/ (free alternative: SourceTree, Git Cola) FreeFileSync: https://freefilesync.org/ (free, but I got the supporter edition because comfy software) In those cases,... - Source: Hacker News / about 1 year ago
  • Ask HN: What project do you donate to?
    Not regularly, but I have donated to: FreeFileSync, an excellent file sync utility within a network. https://freefilesync.org/ StemRoller, separate stems (e.g., voice) from songs. https://www.stemroller.com/ John's Background Switcher, shuffle wallpapers from various sources https://johnsad.ventures/software/backgroundswitcher/ Wikipedia Foundation Etc. - Source: Hacker News / over 1 year ago
  • Ask HN: What Underrated Open Source Project Deserves More Recognition?
    FreeFileSync https://freefilesync.org/ I have been a happy user for years and have made a donation too. - Source: Hacker News / over 2 years ago
  • Which synchronization tool are you using together with the pCloud Crypto Folder?
    FreeFileSync messed up my pCloud database a couple times at first (causing disappearing files in the Crypto Folder, mirroring of the same files over and over again). Pcloud support provided an easy way to fix the database. To fix the root cause, one needs to exclude FreeFileSync's temporary files from the backup: pCloud Drive > Settings > Backup/Sync Exclusions, exclude sync.ffs_lock and *.ffs_tmp. Source: over 2 years ago
  • Why are file backups so slow on Windows 11?
    As per Apprehensive_Arm_754 answer below, https://freefilesync.org is the solution to my particular problem, since it allows all kind of simple rules and logic to apply, so I can make sure that the copy only happens in one direction, and only ever by file date etc. Much appreciated. Source: over 2 years ago
View more

KeptPDF mentions (0)

We have not tracked any mentions of KeptPDF yet. Tracking of KeptPDF recommendations started around Aug 2026.

What are some alternatives?

When comparing FreeFileSync and KeptPDF, you can also consider the following products

Syncthing - Syncthing replaces proprietary sync and cloud services with something open, trustworthy and...

Smallpdf - PDF document management and conversion suite

rsync - rsync is a file transfer program for Unix systems. rsync uses the "rsync algorithm" which provides a very fast method for bringing remote files into sync.

iLovePDF - Premium online PDF tool set

GoodSync - GoodSync provides highly reliable file backup and synchronization for both individuals and businesses.

Sejda - Split, merge and other powerful PDF tools.