Loading tool...
Loading tool...
Test regular expressions with real-time match highlighting and a plain-English breakdown of every token.
Regular expressions are one of the most powerful yet intimidating tools in a developer's toolkit. A well-crafted regex can validate input, extract data, and transform text with remarkable efficiency — but the syntax can be cryptic and error-prone. devmeldex's free regex tester combines real-time pattern matching with a unique plain-English breakdown of every token in your expression. Whether you are a beginner learning regex syntax or an experienced developer debugging complex patterns, this tool makes regular expressions accessible and understandable.
Pattern: [A-Z]{1,2}[0-9][0-9A-Z]?\s?[0-9][A-Z]{2}
Matches: "SW1A 2AA", "EC1A 1BB", "M1 1AA" highlighted in test string
This UK postcode regex matches all valid postcode formats. The explainer breaks it down: one or two uppercase letters, a digit, optional alphanumeric, optional space, digit, two letters.
Type your regex pattern in the pattern field. The tool compiles and validates it in real time.
Toggle flags: g (global), i (case-insensitive), m (multiline), s (dot-all) using the flag buttons.
Paste or type the text you want to test against in the test string textarea.
Matches are highlighted in the text with teal markers. Match details show the matched text, position, and captured groups.
The "Plain-English Explanation" section breaks down every token in your regex into understandable language.
Test email, phone, postcode, and URL patterns before implementing them in your application code.
Build and debug patterns for extracting structured data from logs, CSVs, and unstructured text.
The plain-English explainer helps beginners understand what each part of a regex pattern does.
Use built-in presets for UK postcodes, US ZIP codes, phone numbers, and email validation.