Software Alternatives, Accelerators & Startups

Screen Lock Builder VS KeptPDF

Compare Screen Lock Builder VS KeptPDF and see what are their differences

Screen Lock Builder logo Screen Lock Builder

Create a Windows screen lock .exe with custom message, encryption, and security features.

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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  • Screen Lock Builder Landing page
    Landing page //
    2026-01-30
  • 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

Screen Lock Builder features and specs

  • User-Friendly Interface
    Screen Lock Builder offers an intuitive and easy-to-navigate interface, making it simple for users to customize and set up their screen locks without extensive technical knowledge.
  • Customizability
    The tool provides a wide range of customization options, allowing users to create screen locks that suit their preferences and needs.
  • Security
    Screen Lock Builder incorporates robust security features that help protect user data and devices from unauthorized access.
  • Compatibility
    The application is compatible with multiple operating systems and devices, ensuring broad usability across different platforms.
  • Support Resources
    Users have access to comprehensive support resources, including tutorials and customer service, to assist with any issues they may encounter.

Possible disadvantages of Screen Lock Builder

  • Limited Free Version
    The free version of Screen Lock Builder may have limited features, encouraging users to purchase the full version for complete functionality.
  • Performance Impact
    Some users report a noticeable impact on device performance when using certain advanced features of the Screen Lock Builder.
  • Learning Curve for Advanced Features
    While the basic functions are user-friendly, some of the advanced customization options may require a learning period to fully utilize.
  • Regular Updates Required
    To maintain security and functionality, Screen Lock Builder requires regular updates, which may inconvenience some users.
  • Potential Compatibility Issues
    While generally compatible, some users have experienced compatibility issues with specific device models or OS versions.

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 Screen Lock Builder

Overall verdict

  • Screen Lock Builder from dev-offcode.com can be a solid choice for developers and hobbyists looking to create custom lock screen applications, though its quality depends on your specific needs, platform support, and how actively the tool is maintained. As with any niche developer tool, it's wise to verify current reviews and test the free version before committing.

Why this product is good

  • Provides specialized functionality for building custom screen lock experiences without starting from scratch
  • May offer templates and pre-built components that speed up development
  • Can be useful for learning how lock screen mechanics and security features work
  • Potentially saves time compared to coding a lock screen application manually

Recommended for

  • Developers who need to prototype or build custom lock screen applications
  • Hobbyists exploring UI and security-related app development
  • Small teams wanting a quicker path to a functional screen lock feature
  • Educational use for understanding lock screen and app-building concepts

Category Popularity

0-100% (relative to Screen Lock Builder and KeptPDF)
Security & Privacy
67 67%
33% 33
PDF
0 0%
100% 100
File Encryption
100 100%
0% 0
PDF Readers And Editors
0 0%
100% 100

Questions & Answers

As answered by people managing Screen Lock Builder 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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What are some alternatives?

When comparing Screen Lock Builder and KeptPDF, you can also consider the following products

VBLock - Converged Infrastructure

Smallpdf - PDF document management and conversion suite

ClearLock - A transparent screen locker.

iLovePDF - Premium online PDF tool set

Transparent Screen Lock - Password protect your workstation or server with "Transparent Screen Lock" while monitoring programs that are running.

Sejda - Split, merge and other powerful PDF tools.