Regex Tester: Formats, File Types, and Size Limits

A reference for regex syntax, flags, and how the tool works with text — no uploads, no file limits.

Published August 28, 20264 min read

Formats, options, and limits for Regex Tester

A quick reference for how the tool works.

The tool is text-only. You enter a pattern and sample text, so there are no file types or size limits.

Flag	Meaning
`g`	Global — match all, not just the first
`i`	Case-insensitive
`m`	Multiline — `^`/`$` match line starts/ends
`s`	Dot matches newlines

Pattern `\w+@\w+\.\w+` matches simple email addresses in your sample text.

Regex Tester accepts a pattern, sample text, and flags — no uploads — and reports matches in real time.

A regex pattern, sample text, flags, and an optional replace string.

No uploads are involved, so there are no file type or size limits.

Flags change matching behavior, e.g. g for global, i for case-insensitive, m for multiline.