Software Alternatives, Accelerators & Startups

Syncthing VS KeptPDF

Compare Syncthing 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.

Syncthing logo Syncthing

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

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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  • Syncthing Landing page
    Landing page //
    2022-04-18
  • 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.

Syncthing

Pricing URL
-
$ Details
Release Date
-
Startup details
Country
Germany

KeptPDF

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

Syncthing features and specs

  • Open Source
    Syncthing is open-source software, making it free to use and allowing for community contributions. This fosters transparency and continuous improvement.
  • Privacy
    The software uses peer-to-peer communication, meaning your files are not stored on a third-party server, enhancing privacy and security.
  • Cross Platform
    Syncthing is available on multiple platforms, including Windows, Mac, Linux, and Android, ensuring broad compatibility.
  • Real-time Sync
    The software offers real-time synchronization, which ensures that changes are immediately propagated across all devices, minimizing data inconsistencies.
  • Version Control
    Syncthing provides file versioning features, which can help recover older versions of files in case of accidental deletion or changes.

Possible disadvantages of Syncthing

  • Complex Setup
    Initial configuration and setup might be complex for users who are not technically inclined, requiring a certain level of understanding of network concepts.
  • Resource Usage
    Real-time syncing and continuous operation can consume significant system resources, affecting performance, especially on less powerful devices.
  • No Native Mobile Experience
    While Syncthing is available on Android, there is no official iOS app, which limits its usability for users on Apple's mobile platform.
  • Network Dependency
    Effective synchronization depends on the availability of a reliable network connection, which can be a limitation in areas with poor connectivity.
  • Self-Management
    Unlike cloud-based solutions, Syncthing requires users to handle their own backups, security, and maintenance, which can be time-consuming and complex.

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.

Syncthing videos

Why We Use Syncthing, The Open Source Private File Syncing Tool instead of NextCloud

More videos:

  • Review - Setup and Review of SyncThing, The Open Source File synchronization tool
  • Review - Syncthing for Syncing Both Computers & Phones

KeptPDF videos

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

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Category Popularity

0-100% (relative to Syncthing and KeptPDF)
Cloud Storage
100 100%
0% 0
PDF
0 0%
100% 100
File Sharing
100 100%
0% 0
PDF Readers And Editors
0 0%
100% 100

Questions & Answers

As answered by people managing Syncthing 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 Syncthing and KeptPDF

Syncthing Reviews

15 Best Rclone Alternatives 2022
With this tool, you can synchronize files between multiple computers without hassles. Syncthing is not very different from rclone as it also supports command-line functionality. Also, itโ€™s a free and open source application with all source code available on GitHub.

KeptPDF Reviews

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

Based on our record, Syncthing seems to be more popular. It has been mentiond 852 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.

Syncthing mentions (852)

  • KeepassDX โ€“ open-source Password Manager for Android
    Syncing the database between devices with Syncthing (https://syncthing.net/) is pretty neat too! - Source: Hacker News / 6 days ago
  • Syncthing File Sync for Self-Hosted Knowledge Systems
    Unlike cloud storage platforms, Syncthing uses a peer-to-peer model where each device holds its own copy of synced folders and exchanges changes directly with trusted peers. There is no central server that owns your data, no subscription account, and no vendor lock-in. The project is open-source and community-driven, with more details at syncthing.net. - Source: dev.to / about 2 months ago
  • The Quiet Renovation at Bitwarden
    Been using this setup for many years and never had any problem at all. I sync between desktop and mobile with Syncthing[0]. And also you can configure Syncthing to do file versioning, and it has many options (Trash Can, Simple, Staggered or External file versioning) so if some weird conflict happens you'll never lose data. But honestly, I have never had any issues, and I have been running this setup for many... - Source: Hacker News / 4 months ago
  • Show HN: Stop paying for Dropbox/Google Drive, use your own S3 bucket instead
    Https://syncthing.net/ <- like this :) Free, opensource, works on computers and phones, can in most cases puncture nat, supports local discovery (lan, multicast). No googles, no dropboxes, no clouds, no AI training, no "my kid likes the wrong video on youtube, now our whole family lost access to every google account we had, so we lost everything, including family photos", just sync! (not affiliated, just really... - Source: Hacker News / 5 months ago
  • Seafile vs Syncthing: Server vs Peer-to-Peer
    Syncthing is a decentralized, peer-to-peer file sync tool. Devices connect directly to each other โ€” no central server. It does one thing: keep folders in sync across devices. It does this exceptionally well, with block-level delta sync and strong encryption. - Source: dev.to / 6 months ago
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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 Syncthing and KeptPDF, you can also consider the following products

Dropbox - Online Sync and File Sharing

Smallpdf - PDF document management and conversion suite

Nextcloud - With Nextcloud enterprises host their own secure cloud solution for storage, collaboration & communication from any device, anywhere.

iLovePDF - Premium online PDF tool set

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

Sejda - Split, merge and other powerful PDF tools.