Software Alternatives, Accelerators & Startups

Servo VS KeptPDF

Compare Servo VS KeptPDF and see what are their differences

Servo logo Servo

PHP builder application which uses a combination of a powerful editor and drag & drop to make...

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
  • Servo Landing page
    Landing page //
    2023-09-20
  • 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.

Servo

Website
servo.org
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

Servo features and specs

  • High-Performance
    Servo is designed to take advantage of modern hardware architectures, making it potentially faster in rendering web pages compared to some other engines.
  • Parallelization
    Servo is built to run web elements in parallel, utilizing multicore processors to enhance performance efficiency and speed.
  • Memory Safety
    Written in Rust, Servo benefits from Rust's memory safety features, helping to prevent common programming bugs like buffer overflows and null pointer dereferences.
  • Modularity
    Servo is developed as a collection of independent libraries, which promotes easy testing, maintenance, and potential reuse in various projects.

Possible disadvantages of Servo

  • Incomplete Feature Set
    Servo, being an experimental browser engine, does not yet support all web standards and features that mature engines like Blink or Gecko support.
  • Stability
    As a project in active development, Servo might not be as stable as mainstream engines, which may impact its reliability for everyday use.
  • Limited Adoption
    Due to its experimental nature and ongoing development, Servo has limited adoption in the industry, resulting in less community support and fewer real-world testing scenarios.
  • Compatibility
    Websites optimized for engines like Webkit or Blink might encounter unexpected issues or rendering problems on Servo due to differences in implementation.

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.

Category Popularity

0-100% (relative to Servo and KeptPDF)
Web Browsers
100 100%
0% 0
PDF
0 0%
100% 100
Testing
100 100%
0% 0
PDF Readers And Editors
0 0%
100% 100

Questions & Answers

As answered by people managing Servo 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

Share your experience with using Servo and KeptPDF. For example, how are they different and which one is better?
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Social recommendations and mentions

Based on our record, Servo seems to be more popular. It has been mentiond 71 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.

Servo mentions (71)

  • Hang on to Your Firefox
    Servo exists, and it's making steady progress: https://servo.org/. - Source: Hacker News / about 15 hours ago
  • Leaving Mozilla
    Servo [0] is EU funded via NLnet. You can build a browser from that. [0] https://servo.org/. - Source: Hacker News / 3 months ago
  • Why Embedding Web Content in Rust Was So Painful (Until Now)
    For those unfamiliar, Servo is a web rendering engine originally started at Mozilla Research. It's written in Rust from the ground up and was designed to take advantage of modern hardware through parallelism — layout, styling, and painting can happen concurrently across CPU cores. Many of Servo's innovations actually made their way into Firefox over the years (Stylo, WebRender). - Source: dev.to / 5 months ago
  • Ladybird Browser Adopts Rust
    Firefox was special in that Mozilla created Rust to build Servo and then backported parts of Servo to Firefox and ultimately stopped building Servo. Thankfully Servo has picked up speed again and if one wants a Rust based browser engine what better choice than the one the language was built to enable? https://servo.org/. - Source: Hacker News / 6 months ago
  • Flutter Winit-Wgpu Shell
    So things like media players from the native platform wouldn't be required. in-app browsers can use something like [servo](https://servo.org/) map-gis widgets can use something like [galileo](https://github.com/galileo-map/galileo). - Source: Hacker News / 9 months 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 Servo and KeptPDF, you can also consider the following products

WebKit - WebKit is a layout engine designed to allow web browsers to render web pages.

Smallpdf - PDF document management and conversion suite

Zen Browser - Zen is a beautifully designed browser, privacy-focused, and packed with features, that care about your experience, not your data.

iLovePDF - Premium online PDF tool set

Surf - A simple web browser based on WebKit2/GTK+

Sejda - Split, merge and other powerful PDF tools.