FILExt VS KeptPDF

FILExt's answer

FILExt.com is a specialized online resource that provides comprehensive information about file extensions and the software applications associated with them. What makes FILExt.com unique is its extensive and meticulously curated database of file extension information, which serves as a valuable tool for users trying to identify unknown file types or seeking compatible software to open specific files.

Key Features That Make FILExt.com Unique:

1. Extensive Database: FILExt.com boasts one of the largest collections of file extension information available online, covering a wide range of file types across various platforms and industries.

2. Detailed Information: Each entry includes detailed descriptions of the file type, its purpose, and the software programs that can open, edit, or convert the file, providing users with actionable information.

3. User-Friendly Interface: The website is designed for easy navigation, allowing users to search for file extensions alphabetically or use a search function to find specific file types quickly.

4. Regular Updates: The database is continually updated to include new file extensions and software applications, ensuring that the information remains current and relevant.

5. Community Engagement: FILExt.com often incorporates user contributions, allowing individuals to submit new information or corrections, which helps maintain the accuracy and breadth of the database.

6. Educational Resources: Beyond just listing file extensions, FILExt.com may offer articles and guides that educate users on how to handle different file types, troubleshoot issues, and understand the nuances of file compatibility.

By focusing exclusively on file extensions and their associated applications, FILExt.com provides a niche but essential service that assists users in navigating the complexities of various file formats, making it a unique and valuable resource on the internet.

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.

FILExt's answer

FILExt.com provides a comprehensive and up-to-date database of file extensions with reliable information on how to open them, making it a user-friendly choice 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.

FILExt's answer

The primary audience of FILExt.com is users seeking information about unknown or unfamiliar file extensions, including how to open, use, or convert files with those extensions.

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.

FILExt's answer

FILExt was established in 2000 by Tom Simondi in California and is now based in the heart of Europe. In the 1990s, Tom Simondi worked mainly in computer support, sharing his knowledge with the Internet community. A single file extension page on 'Computer Knowledge' became particularly popular, because this website contained not only the appropriate description but also links to the software manufacturers. PC Magazine has selected Tom's file extension site as one of their Best 100 Undiscovered Sites. Microsoft became aware of this website and integrated it into Windows XP. When XP tried to open a file it did not know how to open it gave the user the option of choosing a local program or go to the Internet to find the answer. The second option resulted in Tom's file extension research page. Due to the great response to this single web page, FILExt.com was launched in 2001.

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.

FILExt's answer

FILExt.com primarily uses Microsoft technologies like ASP.NET for its server-side scripting.

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.

FILExt's answer

Some of FILExt's biggest customers are Fortune Global 500 companies.

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.