Product
Regex Helper
For developers who bounce off regex every time they need one. Paste an English description of what you want to match, or an existing regex that's misbehaving, or one you can't read — get back a working pattern targeted at your flavor (JavaScript / Python / PCRE / grep-BRE), a plain-English breakdown of every piece, three example strings it matches, three near-miss strings it does NOT (with the specific reason), and — on the deep tier — the edge cases most people forget plus a catastrophic-backtracking / ReDoS audit and per-flavor portability notes.
About this tool
What does regex helper do?
For developers who bounce off regex every time they need one. Paste an English description of what you want to match, or an existing regex that's misbehaving, or one you can't read — get back a working pattern targeted at your flavor (JavaScript / Python / PCRE / grep-BRE), a plain-English breakdown of every piece, three example strings it matches, three near-miss strings it does NOT (with the specific reason), and — on the deep tier — the edge cases most people forget plus a catastrophic-backtracking / ReDoS audit and per-flavor portability notes.
How does Regex Helper work?
Pick a mode (generate from English, explain an existing pattern, or fix one that's misbehaving), pick your regex flavor (JavaScript, Python, PCRE, or grep BRE), and optionally paste sample strings you want it to match or not match. One AI pass returns the pattern (without delimiters), the recommended flags, a plain-English one-sentence summary, a fragment-by-fragment breakdown of the pattern, exactly 3 example strings it matches (with the matched span highlighted), and exactly 3 near-miss strings that look like they should match but don't (with a one-line reason each). On the deep tier you also get an edge-case audit, a catastrophic-backtracking (ReDoS) risk assessment with a safer rewrite if needed, and flavor-portability notes for constructs that only work in your chosen engine.
How is this different from asking ChatGPT for a regex?
A freeform ChatGPT prompt hands you a plausible-looking pattern and then leaves you to open regex101 in another tab to check whether it actually works, whether it explodes on failure, and whether it works in the flavor you actually need. Regex Helper runs one structured pass that always ships the pattern together with 3 matches, 3 near-miss non-matches, a per-fragment breakdown, and (deep tier) an edge-case and ReDoS audit. You verify correctness inside the tool, you see exactly which piece of the pattern rejected which piece of a failing input, and you know before you ship whether the pattern will hang on a long adversarial string.
Do you invent regex syntax that doesn't exist in my chosen flavor?
No. Each flavor has explicit hard rules built into the prompt: JavaScript uses (?<name>...) for named captures and does not support (?P<name>...); Python's re module uses (?P<name>...) and does not support possessive quantifiers unless you import the third-party regex module (which the tool tells you about in flavor notes); PCRE supports the full feature set including variable-width lookbehind and atomic groups; grep BRE treats ?, +, |, {, and ( as literal characters unless escaped with a backslash, and has no trailing flags because flags there are command-line switches. If you paste a pattern in fix or explain mode that uses a construct the tool is not fully certain of, it says so in the explanation instead of confidently rewriting it into something wrong.
What is the ReDoS check on the deep tier?
Catastrophic backtracking (ReDoS) is when a pattern like (a+)+ or (a|a)* takes exponential time on a long string that almost matches, freezing your server. The deep tier reads your pattern for the shapes that cause it (nested unbounded quantifiers over the same class, alternation with overlapping branches under a repeat, .* next to another quantifier over the same class), reports a risk level (none, low, medium, high) with the specific shape that triggered it, and suggests a safer rewrite (atomic group in PCRE, possessive quantifier where the flavor supports it, character-class rewrite everywhere else). It is the same check a security review would run on a regex before it goes to production.
Which tier should I pick, Quick or Deep?
Pick Quick (15 tokens) when you know what you want and just need a correct pattern with a breakdown and quick verification (matches and non-matches). It skips the edge-case audit, the ReDoS check, and the flavor-portability notes. Pick Deep (25 tokens) when the pattern is going into production, is going to run on untrusted input, needs to work across engines, or has to handle unicode, whitespace, or multiline edge cases you have not thought through yet. Deep is the tier that turns 'this looks right' into 'this will not embarrass me later'.
How much does it cost per run, and do I need a subscription?
There is no subscription. You spend tokens per run: 15 produde tokens for the Quick tier and 25 for the Deep tier. Tokens are a prepaid platform credit you buy once and spend across any produde tool, so you pay per pattern instead of a monthly fee. If a run fails, the full token cost is refunded to your wallet automatically.
Can I paste my own test strings, or does it generate them?
Both. The test_samples field is optional. If you paste sample strings (one per line), the tool prefers those, and any line prefixed with an exclamation mark ('!') is treated as a non-match sample. If you leave it blank, the tool generates 3 realistic matches and 3 near-misses on its own. Either way you always get exactly 3 of each in the output, with the matched span highlighted on the matches and a one-line reason on the near-misses naming which pattern piece rejected which input piece.
Does it support Python's regex module, PCRE2, or Rust's regex crate?
The four tier-one flavors are JavaScript (ECMAScript), Python (the built-in re module), PCRE, and grep BRE. When a pattern uses a feature that is unsupported or behaves differently outside your chosen flavor (variable-width lookbehind in Python re, possessive quantifiers outside PCRE, named captures with different syntax across engines), the deep tier's flavor_notes lists the exact construct and the portability impact. That includes notes on when you'd need Python's third-party regex module, when to switch grep to -E (ERE) or -P (PCRE), and where a JavaScript lookbehind requires ES2018+. Rust's regex crate is not currently a first-class target because it does not support backreferences or lookaround, so patterns that use those features would need explicit rewriting.
What does it cost?
From 15 tokens. Pick a tier on the form above. Produde tokens are a prepaid platform credit; buy them once and spend on any tool.
Do I pay if a run doesn't complete?
No. You only pay for results. If a run can't finish, its full token cost stays in your wallet automatically.
Is my data stored?
Your input and the run output are saved to your account so you can browse history. They are not sold, shared with advertisers, or used to train shared models. See privacy for details.