Natural Language to Regex
Regex gets forgotten constantly. Describe → Ryna AI writes + explains + gives test cases.
Ryna AI Editorial Team · Updated 03.04.2026
You can picture the pattern clearly — 'catch phone numbers in this format', 'pull dates out of log lines', 'let only valid emails through' — but the moment you hit regex syntax, you stall. One misplaced quantifier and the pattern matches nothing or everything; \d and \w blur together; you go cross-eyed in backslash hell. Regex also has a serious side: in 2019 a single badly-written pattern took Cloudflare offline globally for roughly 30 minutes via catastrophic backtracking. A pattern that 'looks like it works' can lock up a production CPU.
You describe what you want to match to Ryna AI in plain English (or Turkish), state your language/flavor (JavaScript, Python re, PCRE/PHP, .NET, Java, Go RE2, grep/POSIX), and it returns the ready pattern, a token-by-token explanation, should-match and should-NOT-match test strings, and edge-case notes (unicode, empty string, greedy vs lazy, anchors). It works in reverse too: paste a cryptic regex and ask 'what does this do?', or hand it your pattern + the input it fails on and ask 'why does this blow up?'
Never ship regex on blind faith: treat Ryna's pattern as a draft and test it against both positive and negative examples from your own real data. The free plan gives near-unlimited daily messages — you can try and refine dozens of patterns all day. Uploading a real log file, CSV, or screenshot to say 'generate a pattern that catches every order number in this data', or getting a deep-thinking ReDoS analysis of a complex pattern, requires Plus ($12/mo, 399.99 TRY).
Why use Ryna AI for this
Flavor-aware output: JavaScript, Python re, PCRE/PHP, .NET, Java, Go RE2, grep/POSIX — it uses the right syntax for lookbehind, named groups, and unicode behavior.
Token-by-token explanation: it breaks down what every `\d`, `[^ ]`, `(?:...)`, `{2,4}` piece does so you understand the pattern instead of memorizing it.
Automatic test set: it produces should-match AND should-NOT-match example strings together, so you catch over-matching upfront.
Edge-case coverage: it flags empty string, unicode characters, line breaks, greedy vs lazy, and anchored vs unanchored behavior.
ReDoS warning: it flags catastrophic-backtracking risks like nested quantifiers (a+)+ and suggests a safer alternative pattern.
Works both ways: it generates a pattern from a description, and it explains a cryptic regex you paste in plain English or debugs a broken one.
Example prompts
Copy any prompt below and paste into chat.rynaai.com. Each prompt is tuned for a different scenario — try them all to see how Ryna AI adapts.
How it works — step by step
- 1
Describe what to match
On chat.rynaai.com, describe in plain English what you want to match: 'catch invoice numbers in this format' or 'let through only emails ending in .edu'. The more concrete you are, the more accurate the pattern.
- 2
State the flavor and the goal
Which language/engine: 'JavaScript', 'Python re', 'PCRE', 'Go RE2', 'grep' — because lookbehind, named groups, and \d's unicode behavior vary by flavor. Also say your goal: validation, or extraction from within text?
- 3
Give positive and negative examples
Include 3-4 strings that should match AND 3-4 that should not: 'these must pass: ... these must fail: ...'. Negative examples are the strongest signal for preventing over-matching.
- 4
Ask for explanation and tests
Say 'explain the pattern token by token and give a test table with matching and non-matching examples'. That way you see what works and why before you copy-paste, and it teaches a junior developer too.
Example: input → output
You ask
JavaScript. Validate a US phone: optional +1, area code with or without parentheses, spaces or dashes allowed. Give should-match and should-not-match examples.
Ryna AI returns
```js /^(?:\+1[ -]?)?\(?\d{3}\)?[ -]?\d{3}[ -]?\d{4}$/ ``` **Token breakdown** - `^ … $` — validates the whole string end to end - `(?:\+1[ -]?)?` — optional +1 country code with a separator - `\(?\d{3}\)?` — 3-digit area code, parentheses optional - `[ -]?` — optional space or dash separator - `\d{3}[ -]?\d{4}` — the remaining 7 digits **Test table** | Input | Result | |---|---| | +1 (415) 555-2671 | matches | | 415-555-2671 | matches | | 4155552671 | matches | | 415-555-267 | no match (too short) | | (415) 55-2671 | no match (wrong grouping) | **Edge notes:** The pattern validates *format* only, not that the number is real or active. Because separators are loose, it also accepts unbalanced parentheses like '415)-555-2671'; if you need strict formatting, require matched parens with a stricter group. It has no nested quantifiers, so no ReDoS risk, and it also compiles cleanly in Go RE2.
Pro tips
- Give not just should-match but should-NOT-match examples — negatives are what prevents over-matching most.
- Always state the flavor: lookbehind exists in JS and PCRE but not Go RE2; \d matches unicode digits in some flavors — say [0-9] if you want ASCII-only.
- Ask it to 'use named groups' for readability — (?<year>\d{4}) lets you grab captures by name instead of index, which is far easier to maintain in code.
- Ask 'any ReDoS risk from nested quantifiers like (a+)+, and give a safe version' — non-negotiable for production patterns.
- Separate validating the whole string from searching within it: use ^...$ anchors for validation, drop them for search/extraction — otherwise you'll reject valid data.
- Ask for both a 'strict' and a 'lenient' version of the same job — one for exact format, one to catch the real world's messy data.
Common mistakes to avoid
- ✕Asking for a pattern without stating the flavor — a lookbehind pattern that works in JS won't even compile in Go RE2.
- ✕Giving only positive examples — the pattern matches more than you intended and silently produces false positives on real data.
- ✕Mistaking regex for email 'validity' — a pattern catches typos but can't verify the mailbox actually exists; deliverability needs SMTP/verification.
- ✕Shipping to production without testing on real data — 'it compiles' is not the same as 'it matches correctly'.
- ✕Blindly copying a pattern with nested quantifiers — structures like (.*)* are ReDoS-prone and lock the CPU on large input.
Who this is for
Devs, data analysts, DevOps, anyone parsing logs.
FAQ
Which languages and regex flavors are supported?
JavaScript, Python re, PCRE/PHP, .NET, Java, Go RE2, Ruby, and grep/POSIX. State your flavor upfront: RE2 doesn't support lookaround or backreferences, and Ryna warns you and offers an alternative.
Does regex validate emails perfectly?
No. A full RFC 5322 pattern is enormous and impractical; regex catches typos (missing @, double dots) but can't confirm the mailbox exists. Real deliverability needs a verification/SMTP service — Ryna gives you a fit-for-purpose 'good enough' pattern.
Does it warn about catastrophic backtracking / ReDoS?
Yes, just ask. It flags nested-quantifier risks and suggests a backtracking-free, RE2-style safe alternative. For complex patterns, deep thinking on Plus does a more detailed analysis.
Will it explain a cryptic regex I already have?
Yes, it works in reverse. Paste the pattern and it gives a plain-English token-by-token explanation, examples of what it matches, and any hidden bugs (wrong anchor, missing escape).
Can I upload a log or CSV to derive a pattern from the data?
Yes, but file/PDF/screenshot upload is a Plus feature ($12/mo, 399.99 TRY). On the free plan you paste sample lines as text; with near-unlimited daily messages you can iterate and refine as much as you want.
Related use cases
Free — near-unlimited daily messages
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