Regex Validator

WHAT IT DOES

Regex Validator is a developer tool that tests regular expression patterns against strings. Enter a regex pattern, optional flags (e.g., i for case-insensitive, g for global), and a test string — the tool validates the pattern syntax, executes the match, and displays detailed results including whether the pattern matches, the number of matches, match groups, and the index of each match. This is essential for developers writing and testing regex patterns for data validation (Ethereum addresses, hex strings, email addresses, dates), parsing logs, or extracting information from text.

HOW TO USE

Connect your wallet using the BGWallet bridge (MetaMask or any Web3 wallet). Enter the regex pattern in the pattern field — for example, ^0x[a-fA-F0-9]{40}$ to validate Ethereum addresses. Enter optional flags (e.g., i for case-insensitive, g for global matching). Enter the test string in the text area. Click "Test match" to run the validation. The tool displays the pattern, flags, status (match found or no match), test string preview, number of matches, match groups, and a detailed table of matches with their indices and captured groups. Use the "Load samples" button to load pre-defined patterns for Ethereum addresses, token codes, emails, dates, and decimal numbers. This is useful for quickly testing common regex patterns.

TECHNICAL MECHANISM

The tool uses JavaScript's built-in RegExp engine for pattern matching. It constructs a RegExp object from the pattern and flags strings, handling any syntax errors gracefully. It then uses regex.test() to check if the pattern matches at least once, regex.exec() for detailed match information, and String.matchAll() to get all matches with their indices and groups. The tool displays the test string (truncated if long), the number of matches, and a table of matches with their index positions and captured groups. The tool validates the regex pattern before execution — if the pattern is invalid, it displays the error message from the RegExp constructor. All operations are performed client-side — no data is stored or transmitted. The tool is read-only and does not sign any transactions.

WHAT IT CANNOT SEE

The tool cannot validate regex patterns that require external data or context — it only tests the pattern against the provided string. It cannot guarantee that the regex pattern matches the intended input format for all cases — the test is limited to the provided test string. It cannot handle extremely complex regex patterns without performance degradation — very complex patterns may cause slowdowns. It cannot provide guidance on regex syntax beyond basic validation — the tool does not teach regex. It cannot validate regex against non-string data types — only strings are supported. It cannot match patterns across multiple lines unless the appropriate flags are set. The tool is read-only and does not sign any transactions.

PLEASE NOTE

This tool works exclusively with EVM-compatible chains for the wallet connection, but the regex validation is chain-agnostic. Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported for wallet connection but the validation works regardless. The tool uses JavaScript's RegExp engine — syntax may differ from other regex implementations (e.g., PCRE, Python). The tool does not store any data — all operations are performed client-side. The tool is provided as-is with no warranty or liability. Always verify regex patterns thoroughly before using them in production code.