RegExpress
Powerful Regex Testing Tool
Free · In‑App Purchases
Build, test, explain, and optimize regex with five engines, a focused editor, visual tools, test suites, code generation, and a generous free tier.
RegExpress is a complete regular expression toolkit for iPhone, iPad, and Mac. Create, test, understand, and refine regex patterns in one focused workspace, whether you are learning the basics or maintaining production expressions.
Test with the flavor you actually use. RegExpress supports Swift Regex, Foundation (ICU), JavaScript/ECMAScript, Python Compatibility Mode, and native PCRE2. Flavor-aware options, syntax references, examples, diagrams, comparisons, and compatibility details help you spot differences before they become bugs.
Write and test with confidence
See live matches and capture groups as you type. Switch between automatic and manual execution, inspect clear errors, and keep the editor responsive during demanding patterns. Built-in safety analysis identifies potential backtracking risks, while find and replace lets you preview changes before applying them.
Focus on complex patterns
Open the multiline Focus Editor for more room, syntax-aware tools, a persistent token dock, flavor-specific options, visual railroad diagrams, code snippets, and quick access to the Pattern Builder, test suites, and reference material.
Understand and improve every expression
Turn plain-language requirements and examples into a regex. Explore explanations, recommendations, optimization suggestions, debugging tools, diagrams, and a searchable cheat sheet. Compare patterns by matches, compatibility, and performance to choose the right approach.
Build a reusable regex workflow
Save patterns, organize them into folders and automatic collections, keep history, and create test suites with positive and negative cases. Save complete .regexpress workspaces, reopen .regproj test projects, import shared content, and generate code for your project. A command palette, Spotlight integration, App Shortcuts, multiwindow support, and sharing tools keep common actions close at hand.
Learn by doing
Browse flavor-aware examples, follow guided tutorials, use the syntax reference, and practice with challenges designed for different skill levels.
A useful free experience
Core editing, unlimited live matching, all five engines, standard options, capture results, find and replace, examples, reference material, and Swift code generation are free. You can also save up to 20 patterns, keep 50 recent history items, create one test suite with up to 10 manual cases, and use selected previews of advanced tools.
RegExpress Pro is available as a one-time purchase with no subscription. Pro unlocks deeper debugging and performance analysis, complete visual tools, advanced generation and optimization, additional code targets, unlimited tests and saved content, iCloud sync, advanced organization, and more.
Whether you need a quick match, a visual explanation, or a repeatable testing workflow, RegExpress helps you build regex with clarity and confidence.
- This app’s overall rating was recently reset.
Version 8 is a major upgrade built around safer execution, flavor accuracy, and a faster professional workflow.
Meet the new Focus Editor, a multiline workspace with a persistent token dock, flavor-aware options, railroad diagrams, code snippets, and direct access to building and testing tools.
Run expressions with five distinct engines: Swift Regex, Foundation (ICU), JavaScript/ECMAScript, Python Compatibility Mode, and native PCRE2. Options, examples, the cheat sheet, Pattern Builder, optimizer, comparisons, and diagrams now adapt to the selected flavor.
Execution is more responsive and reliable, with automatic or manual runs, cancellation, clearer errors, match limits, and improved protection from expensive backtracking.
Save complete .regexpress workspaces, reopen .regproj test projects, and keep patterns, options, text, replacements, tests, notes, and metadata together. Structured local storage and sync improvements make saved work more dependable.
Test suites now include richer results, edge-case intelligence, performance limits, progress, cancellation, and pattern health details. Pattern comparison now includes flavor-aware match, compatibility, and performance differences.
Generate Regex has been redesigned around plain-language requirements, positive and negative examples, strictness, portability, expected captures, previews, and refinement. Recommendations, optimization, examples, and automatic library collections have also been improved.
New productivity features include the command palette, Spotlight search, App Shortcuts, Share Extension support, deep links, incremental replacement previews, and improved workspace sharing.
Version 8 also introduces a clearer free tier. Core regex creation and testing remain free, with useful allowances for saved patterns, history, test cases, Generate Regex, and previews of advanced tools. RegExpress Pro remains a one-time purchase with no subscription.
This release also includes redesigned Examples, keyboard and scrolling fixes, accessibility improvements, localization updates, and many reliability refinements throughout the app.
The developer, Nevv Atlantis LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Nevv Atlantis LLC
- Size
- 8.4 MB
- Category
- Developer Tools
- Compatibility
Requires iOS 16.6 or later.
- iPhone
Requires iOS 16.6 or later. - iPad
Requires iPadOS 16.6 or later. - Mac
Requires macOS 13.5 or later.
- iPhone
- Languages
English and 3 more
- English, Portuguese, Simplified Chinese, Spanish
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- RegExpress Pro $4.99
- Copyright
- © Nevv Atlantis LLC 2026

