AppTools Regex Tester vs Retest

AppTools Regex Tester is a free browser-based tool for checking and debugging regular expressions. Its interactive sandbox updates matches as a pattern changes, with Global, Case-Insensitive, Multiline, DotAll, and Unicode flags. Listed regex flavors are JavaScript, PCRE (PHP), Python, and Go. A parser breaks tokens into human-readable explanations, including quantifiers and non-capturing groups, while a step-through debugger helps inspect pattern behavior. Full matches and capture groups are shown in different colors. The maker describes uses such as parsing logs, validating JSON payloads, cleaning datasets, creating input filters, writing scrapers, and transforming strings in CI/CD pipelines. The regex engine runs in the browser, and the maker says test strings are not transmitted over the network. The privacy policy says inputs stay in browser memory; minimal cookies and local storage retain interface preferences and language settings. AppTools also collects anonymous telemetry about tool popularity. The suite requires no sign-up, subscription, or installation and provides a global support contact. The Free plan is listed at free.

Retest is a free, open-source terminal utility for developing and checking regular expressions on Linux. A subject string can be supplied as an argument or piped through standard input, so it can fit into shell workflows. Retest finds all non-crossing matches and highlights nested capture groups in colors distinct from the whole match. An optional formatted list shows match order and string indexes. Release 0.2.2 added a flag for reading the subject from a file. The project provides Linux release binaries, including a 64-bit Debian installer listed for release 0.2.2. Its README describes compiling from source with Cargo and installing through a Makefile. The source code and documentation are licensed under Apache License 2.0. The project presents Retest as a terminal-based alternative to regex101, for developers building and checking patterns. No paid plans or usage limits are listed.