Regular expressions (regex) are one of the most powerful tools for parsing text — but they are also famously hard to write from scratch. A regex generator solves that: paste your text, pick an extraction mode, and get a working pattern instantly.
What Can You Extract?
The regex generator supports four extraction modes. Exact Value matches a specific string you already know. After Keyword pulls the number that follows a label such as "target level" or "price:". All Numbers extracts every integer and decimal in one pass. Custom lets you specify a prefix and suffix and captures everything in between.
Each mode generates a different regex pattern, tests it against your input instantly, and shows the matches highlighted in the original text.
Step 1: Paste Your Sample Text
Open the Regex Generator and paste a representative sample of the text you want to process. It could be a log line, a game notification, a scraped web page snippet, or any structured string.
The more representative your sample, the more reliable the generated regex will be across real data.
Step 2: Choose an Extraction Mode
Select the mode that matches your goal. If you want the number after a keyword like "bounceRate:", use After Keyword and type bounceRate. If you want every number in the text, pick All Numbers. If you are extracting the content between two fixed strings, use Custom and fill in the prefix and suffix.
Each mode shows a short hint explaining exactly what the generated pattern will do, so there is no guesswork.
Step 3: Generate and Test
Click Generate Regex. The tool builds a pattern, runs it against your sample text, and displays results immediately: the raw regex string, a list of all matches, and the original text with matches highlighted in yellow.
If the result is not quite right, adjust the keyword or affix and generate again. Because everything runs in the browser, there is no round-trip delay.
Step 4: Copy the Code
Switch between JavaScript, Python, and Java tabs to get a ready-to-paste code snippet. Copy it directly into your project.
The JavaScript snippet uses the standard exec loop, the Python snippet uses re.findall, and the Java snippet uses Pattern and Matcher from java.util.regex — all production-ready with no extra dependencies.
Privacy and Speed
Like all tools on MDFileConverter, the regex generator runs entirely in your browser. Your text is never sent to a server, which means it works offline and on sensitive data without any risk.
Pattern generation and testing are instant regardless of input length because the JavaScript regex engine handles everything client-side.