Underlayer vs GrepEx
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Underlayer
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UNDERLAYER - STEGANOGRAPHY MADE SIMPLE Transform ordinary images into secret carriers. Hide confidential messages invisibly within photos and share them through any messenger without raising suspicion. KEY FEATURES: HIDE SECRETS β’ Embed text messages invisibly into any image β’ Two encoding modes: Hidden (invisible pixels) and Open (colored frame) β’ Open mode survives messenger compression (Telegram, WhatsApp, etc.) β’ Share processed images directly or save to gallery REVEAL MESSAGES β’ Extract hidden text from steganographic images β’ Automatic detection of encoding method β’ Works with images received through messengers β’ Share intent support - open images directly from gallery WHY UNDERLAYER? β’ Simple & Intuitive - No cryptography knowledge required β’ Messenger-Friendly - Open mode designed for compressed sharing β’ Privacy First - All processing happens locally on your device β’ Universal - Works with JPG, PNG, WebP formats β’ No Account Required - Start using immediately USE CASES β’ Private communication through public channels β’ Watermarking images with hidden ownership data β’ Secure note-taking in plain sight β’ Educational tool for learning steganography β’ Fun way to send secret messages to friends SECURITY & PRIVACY β’ No internet connection required for processing β’ Your messages never leave your device β’ No data collection or tracking β’ Complete control over your secrets PREMIUM FEATURES β’ No banner ads at the bottom β’ No interstitial ad interruptions β’ Process unlimited images without ad breaks HOW IT WORKS 1. Select any image from your gallery 2. Enter your secret message 3. Choose encoding mode (Hidden or Open) 4. App embeds message into image pixels 5. Share through messengers or save locally 6. Recipient opens image in Underlayer to reveal message ENCODING MODES EXPLAINED HIDDEN MODE β’ Message embedded invisibly in image pixels β’ Completely undetectable to human eye β’ Best for uncompressed image sharing β’ Lost when image is compressed by messengers OPEN MODE β’ Message encoded as colored frame border β’ Visible as decorative edge around image β’ Survives Telegram, WhatsApp compression β’ Recommended for messenger sharing INTERNATIONAL β’ Available in English and Russian β’ More languages coming soon β’ Automatic language detection Whether you're a privacy enthusiast, security professional, or just curious about steganography - Underlayer makes it accessible to everyone. Download now and start hiding your secrets in plain sight! Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
GrepEx
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GrepEx is the ultimate regex and dorking toolkit for developers, security researchers, and power users. Generate production-ready regular expressions in 22 programming languages and build precise search queriesβall from your pocket. REGEX GENERATOR Stop wrestling with regex syntax. Select what you need to match, and GrepEx generates the pattern with language-specific code you can copy directly into your project. β’ 22 Languages: JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, Swift, Kotlin, TypeScript, Perl, Bash, PowerShell, and more β’ 80+ Templates: Email, URL, IP address, phone numbers, dates, credit cards, passwords, file paths, log parsing, and dozens more β’ Live Testing: Paste sample text and see matches highlighted instantly β’ Pattern Explanation: Understand what each regex component does in plain English β’ Safe Testing: Built-in protection against catastrophic backtracking (ReDoS) SEARCH DORKING ENGINE Craft advanced search queries to find exactly what you're looking for. Perfect for research, competitive analysis, and discovering hard-to-find resources. β’ Visual Query Builder: Combine operators like site:, filetype:, inurl:, intitle:, and intext: without memorizing syntax β’ 3,600+ GHDB Templates: Access the GHDB with categorized, searchable dork patterns β’ Smart Exclusions: Filter out noise with preset exclusion lists for cleaner results β’ One-Tap Search: Open your crafted query directly in your browser BUILT FOR PRODUCTIVITY β’ History & Favorites: Never lose a pattern you've created β’ Export & Import: Back up your patterns and transfer between devices β’ Dark Mode: Easy on the eyes during late-night coding sessions β’ VoiceOver Support: Full accessibility for all users PRIVACY FIRST Your data never leaves your device. No accounts, no cloud sync, no analytics, no tracking. GrepEx works entirely offline for core features. GREPEX PRO Unlock unlimited potential: β’ Save unlimited patterns and dorks β’ Access all 22 programming languages β’ Full GHDB search and save β’ Extended history (100 items) β’ Export/Import functionality Whether you're validating user input, parsing log files, scraping data, or conducting security research, GrepEx puts professional-grade tools in your hands. Download GrepEx and master regex today.
Screenshots
Verdict
The clearest difference is price: Underlayer at Free against GrepEx's $1.99. GrepEx's advantage is in-app purchases (none vs 1) and ads (none vs shown). On device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Underlayer is free to download; GrepEx costs $1.99 up front. Underlayer sells 1 in-app purchase, starting at $2.99 per 7 days. GrepEx asks for nothing beyond the download.
Underlayer ships an update every 5 months, GrepEx weekly. The most recent releases landed on October 1, 2026 and October 7, 2026 respectively.
| Parameter | Underlayer | GrepEx |
|---|---|---|
| Price | Free β better | $1.99 |
| Update frequency | Every 5 months | Weekly β better |
| Ads | Yes | No β better |
| In-app purchases | Yes | No β better |
| Devices | iPhone, iPad, iPod β better | iPhone, iPod |
| Requires iOS | 15.1 | 13.4 β better |
| Further details β not scored | ||
| Size | 169 MB | 12 MB |
| Age rating | 4+ | 4+ |
| Developer | Mihail Rukavishnikov | Jeremy Laratro |
In-app purchases
Underlayer
- Premium$2.997 Days
GrepEx
No in-app purchases









