Nitro PDF Pro vs knowb4usign
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Nitro PDF Pro
Edit, read, sign, and secure PDF documents on your iOS device. This powerful yet lightweight app allows for on-the-go productivity with features like text editing, annotation, form filling, and cloud syncing.
- Edit PDF text
- Annotate and highlight PDFs
- Fill and save PDF forms
- Sign and share PDF documents
- Password protect PDFs
- Sync with cloud storage
- Merge and organize PDFs
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Ready to do more with PDFs on iPad & iPhone? Edit, read, sign and sync PDFs in the cloud with the powerful, lightweight Nitro PDF Pro app designed for iPad & iPhone users. Packed with features to help you stay productive on the go, Nitro PDF Pro for iPad & iPhone lets you edit, sign, share and manage your documents wherever you are - all in a secure and user-friendly interface. Get started for free with a 14-day trial today. “Superior PDF handling, & economical” “Nitro PDF Pro has become an essential tool in my daily business operations! It makes everything from document preparation to communication much easier for me.” “If you are looking for a workhorse app to handle your PDFs made by responsive developers, look no further...” -> With Nitro PDF Pro you can: EDIT PDFs ON THE GO * Easily edit PDF text wherever you are, on any iOS device * Make notes and add comments to PDFs for quick, on-the-go reference * Add images or mark-up PDFs with drawings, with stylus support for iPad ANNOTATE & HIGHLIGHT PDFs * Add annotations to PDF text and documents * Highlight text to stay organized and keep track of important information FILL & SAVE PDF FORMS * Fill and save PDF forms for fast & easy productivity * Keep your PDF forms secure with password protection SIGN & SHARE PDF DOCUMENTS * Sign & share PDF documents in a snap * Save text, signatures and images in your Library for easy re-use * Keep documents synced with the cloud for on-the-go signatures PROTECT, SECURE & SYNC PDFs * Password protect PDFs to keep your data and confidential information secure * Set the level of document encryption as required * Sync with the cloud to back up PDFs on iCloud, Dropbox, Google Drive, or Microsoft OneNote MERGE, EXPORT & ORGANIZE PDFs * Merge multiple documents into one PDF in just a few clicks for easy organization * Import, export & organize PDFs in folders for fast access and easy on-the-go editing * Duplicate, add, delete or rearrange pages for simple, custom document creation ADDITIONAL AMAZING PDF EDITOR FEATURES * Duplicate, add, delete, rotate and rearrange pages * Enable easier PDF reading with dark mode, search and zoom * Email & Airdrop your documents, with PDF flattening for maximum compatibility * View two documents simultaneously with multiple windows (iPadOS) * Bluetooth pressure-sensitive stylus support - automatically works with Apple Pencil * Support for Adonit Jot Touch and Jot Script styluses Still exploring PDF editors for iOS? No pressure! Give Nitro PDF Pro iOS a try for free with a 14-day trial and see how you like its features and functions. We think you’ll love the value we pack into our easy-to-use PDF iOS app. Questions and issues regarding our PDF app? We're here to help! Connect with Nitro through our Community Forum: https://community.gonitro.com/ NITRO POLICY https://www.gonitro.com/legal/privacy-policy https://www.gonitro.com/legal/terms-of-service
knowb4usign
This app provides plain-English summaries of legal documents like contracts, leases, and terms of service. It breaks down complex clauses, highlights your obligations and rights, and assigns a risk score for quick understanding. Upload or scan documents for an instant AI review.
- Plain-English contract summaries
- Clause-by-clause breakdown
- Identification of obligations and rights
- Risk assessment score
- Document upload and camera scanning
- AI-powered review
- Follow-up question chat
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Read what you sign. knowb4usign turns any contract, NDA, lease, EULA, or terms-of-service into a plain-English summary you can actually understand. Upload from your phone or scan paper documents with your camera — get a clause-by-clause breakdown in seconds. WHAT YOU GET FOR EVERY CONTRACT • A one-line takeaway in human language • Your concrete obligations — what YOU have to do • Watch-outs and unusual terms (rated Standard, Unusual, or Aggressive) • Rights you retain even after signing • A 0–100 score with a tier label so you know at a glance how the contract reads WORKS ON • Job offers and employment agreements • Apartment leases and real estate contracts • Vendor contracts and SOWs • NDAs and confidentiality agreements • EULAs and software license terms • Terms of service and privacy policies HOW IT WORKS 1. Sign in with Apple, Google, or email 2. Upload a PDF or Word doc — or use your camera to scan paper 3. Get an instant AI review in plain English 4. Ask follow-up questions in chat — "what does this mean if I quit?" PRIVACY FIRST • Sign in with Apple is supported — you can use Hide My Email for full privacy • Documents are analyzed and processed; not used to train AI models • Delete your account anytime from inside the app • Full privacy policy at knowb4usign.com/privacy WHY KNOWB4USIGN Most people skim a 40-page contract because they're tired and the alternative is paying a lawyer to read it. knowb4usign is the in-between. Plain-English review of every clause, in your pocket, available the moment you need it. Free to start — 1 free contract review with no credit card required. Paid plans unlock higher volume and team features. Built by Pexora LLC. Read what you sign.
Screenshots
Verdict
The clearest difference is rating: knowb4usign at 5.0 against Nitro PDF Pro's 3.9. knowb4usign also leads on in-app purchases (none vs 2) and update cadence (every 2 weeks vs every 2 months). Nitro PDF Pro's advantage is ratings volume (161 vs 1). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Nitro PDF Pro sells 2 in-app purchases, starting at $19.99 per year. knowb4usign asks for nothing beyond the download.
knowb4usign holds the better App Store score, 5.0 against 3.9. That said, the two scores are not equally well evidenced: Nitro PDF Pro has 161 ratings behind it against 1, so its average is the more settled of the two.
Nitro PDF Pro ships an update every 2 months, knowb4usign every 2 weeks. The most recent releases landed on September 26, 2026 and September 13, 2026 respectively.
| Parameter | Nitro PDF Pro | knowb4usign |
|---|---|---|
| Price | Free | Free |
| Rating | 3.9 (161 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 12.5% of reviews | — |
| Number of ratings | 161 — better | 1 |
| Update frequency | Every 2 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 18.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 59 MB | 23 MB |
| Age rating | 4+ | 4+ |
| Developer | Nitro Software, Inc. | Pexora LLC |
Bugs and requests
Nitro PDF Pro
Reported bugs
19 issues- Cannot reorder PDF files
- Crashes when opening PDFs from websites/email
- Does not save markups or documents
- Difficulty creating new folders
- Cannot rotate pages
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- Cannot markup/draw on PDFs with editing disabled
- Does not save documents after editing
- Cannot rotate PDFs
- Program freezes up
- Fails to save after deleting pages
- App crashes after update
- Editing is lost prior to crash
- Crashes every time to edit a PDF
- Cannot handle deleting pages
- Crashes when opening fillable PDFs
- Crashes when typing in fields
- No Apple Pencil support
- Stylus link gives 404 error
- Bugs like suddenly not being able to draw
Requested features
10 requests- Keyboard support (Cmd + F for search)
- Ability to cancel search with Esc
- OCR and conversion to text documents on tablets
- User manual for iPad app
- Support for Apple Pencil
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- Ability to create table of contents
- Ability to create fillable forms
- Ability to rearrange pages
- Ability to add to library
- More intuitive interface
knowb4usign
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Nitro PDF Pro
- Annual Subscription14 Days trial$19.991 Year
- Nitro PDF Pro for iOS$9.99
knowb4usign
No in-app purchases
Questions
Is Nitro PDF Pro free?
Is knowb4usign free?
Which has better reviews, Nitro PDF Pro or knowb4usign?
Do Nitro PDF Pro or knowb4usign have ads?
Which is updated more often, Nitro PDF Pro or knowb4usign?
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