Software Alternatives, Accelerators & Startups

Quad9 VS KeptPDF

Compare Quad9 VS KeptPDF and see what are their differences

Quad9 logo Quad9

Quad9 is a free, recursive, anycast DNS platform that provides end users robust security protections, high-performance, and privacy.

KeptPDF logo KeptPDF

Redact, edit, OCR, and sign PDFs entirely in your browser. The file never leaves your device. Free, no account needed.
Visit Website
  • Quad9 Landing page
    Landing page //
    2021-09-24
  • 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.

Quad9

Website
quad9.net
Pricing URL
-
$ Details
-
Release Date
-

KeptPDF

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

Quad9 features and specs

  • Privacy-Focused
    Quad9 does not store any personal data about users and maintains a stringent privacy policy, ensuring that your DNS queries are not tracked or sold to third parties.
  • Security
    Quad9 provides robust security features by blocking access to known malicious domains, which helps protect users from phishing, malware, and other online threats.
  • Performance
    With a global network of servers, Quad9 offers fast DNS resolution, which can contribute to quicker website load times and improved overall internet browsing experience.
  • Easy to Set Up
    Changing your DNS to Quad9 is straightforward and can be easily configured on most devices without requiring technical expertise.
  • Free Service
    Quad9 offers its DNS services free of charge, making it an accessible option for anyone looking to improve their online privacy and security without additional costs.

Possible disadvantages of Quad9

  • Limited Customization
    Quad9 does not offer as many customization options as some competing services, which may be a drawback for advanced users looking for more control over their DNS settings.
  • Possible Geolocation Issues
    Using a global DNS resolver like Quad9 can sometimes lead to geolocation issues, where content or services are delivered based on server location rather than user location.
  • Not as Established
    Quad9 is a relatively new entrant in the DNS space compared to longstanding providers like Google Public DNS and OpenDNS, which might make some users hesitant.
  • Dependency on Upstream Filters
    Quad9's security filtering relies on upstream threat intelligence providers. Therefore, the comprehensiveness of the protection is dependent on the accuracy and timeliness of these third-party sources.

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 Quad9

Overall verdict

  • Yes, Quad9 is generally considered a good DNS service.

Why this product is good

  • Quad9 offers a DNS service that prioritizes security, privacy, and performance. It blocks known malicious domains using threat intelligence from multiple sources, enhancing cybersecurity for its users. Additionally, Quad9 respects user privacy by not logging or selling personal data.

Recommended for

  • Individuals and organizations seeking enhanced security against phishing and malware.
  • Users concerned about privacy and looking for a DNS provider that respects these values.
  • Anyone needing a reliable and fast DNS resolver for their internet activities.
  • IT administrators interested in a robust, secure DNS solution for networks.

Quad9 videos

Quad9 9.9.9.9 VS Google 8.8.8.8 Benchmark Testing & Keeping Your Computer safer with Quad9 DNS

More videos:

  • Review - Quad9 on PS4!! DNS Settings 9.9.9.9 (My Review)
  • Review - Keep your data and computer safe with Quad9
  • Review - Here's Why DNS Matters w/ John Todd from Quad9

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 Quad9 and KeptPDF)
DNS
100 100%
0% 0
PDF
0 0%
100% 100
Security & Privacy
92 92%
8% 8
PDF Readers And Editors
0 0%
100% 100

Questions & Answers

As answered by people managing Quad9 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 Quad9 and KeptPDF

Quad9 Reviews

Best DNS servers of 2022: Boost your internet speed with these free, public services
The company sells itself on its ability to block malicious domains by collecting intelligence from 'a variety of public and private sources.' It's not clear what these sources are, but the website says Quad9 used 18+ 'threat intelligence providers' as of December 2018.
Best DNS Servers to Use for Free in 2022
As the name Quad9 suggests, their primary DNS is 9.9.9.9. Quad9’s DNS is fairly easy to remember as the name indicates. Quad9 focuses on security, performance, privacy, and speed. Though it may not be the fastest DNS, it surely is one of the best DNS servers. Quad9 was built on the factor of security, focusing mainly on protecting its users
Best free DNS servers: 14 options to check out
Quad9 emphasizes security, privacy and performance — the company was founded on the goal to make the internet safer for everyone. It blocks malicious domains, phishing and malware while maintaining your anonymity. Quad9 is constantly expanding to new regions. Right now, it comes in at No. 8 on the DNS Performance Analytics and Comparison ratings.

KeptPDF Reviews

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

Based on our record, Quad9 seems to be more popular. It has been mentiond 49 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.

Quad9 mentions (49)

  • The Great DNS Trail
    So assuming the answer to a query of what something like dev.to is mainly starts at the locally designated DNS servers. This will most likely be your ISP but it's not uncommon to utilize public DNS servers such as Quad9, Google, and Cloud Flare. Public DNS servers were popularized after "certain ISPs" decided that showing ad littered pages for unknown domains was a good idea. - Source: dev.to / 4 months ago
  • AT&T Paid a Hacker $370k to Delete Stolen Phone Records
    Maybe consider using https://quad9.net for DNS? It's nice having archive.today work. Otherwise you can always copy/paste the link to TFA into https://archive.org. - Source: Hacker News / about 2 years ago
  • Information Security Best Practices
    Automate everything. Use a password manager, enable automatic updates, use DNS malware filtering at router level (Free with https://quad9.net ). Source: almost 3 years ago
  • Firefox has surpassed Chrome on Speedometer
    Depends on your region and what sites you're using. I live in the middle of nowhere far from civilization, and 1.1.1.1 returns terrible IPs for many sites including google.com (which pings at 350-400 ms if you resolve it through 1.1.1.1, but at 90-100 ms if you're using any other resolver). They do it because they block EDNS0 in order to protect your privacy or something like that. So I use 8.8.8.8 and 9.9.9.9 in... - Source: Hacker News / about 3 years ago
  • 96 ms to a DNS server OK?
    9.9.9.9 is run by Quad9. They’re more privacy oriented, afaik. Source: about 3 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 Quad9 and KeptPDF, you can also consider the following products

NextDNS - Block ads, trackers and malicious websites on all your devices.

Smallpdf - PDF document management and conversion suite

1.1.1.1 - The free app that makes your Internet safer.

iLovePDF - Premium online PDF tool set

OpenDNS - OpenDNS provides faster and safer Internet access for your home or Business.

Sejda - Split, merge and other powerful PDF tools.