{"uid":"cap_N9NZpodA6Qj3l8lstIP4j","slug":"regex-explainer-plain-english-token-by-token-breakdown-c6a7d479","name":"Regex Explainer – Plain English Token-by-Token Breakdown","description":"Explain what a regular expression matches, in plain English, token by token.","url":"https://api.24klabs.ai/api/explain-regex","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"regex":{"type":"string"}}},"responseSchema":{"type":"json","example":{"explanation":"..."}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.006","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.006/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.006","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.006","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_bzVdbPzMKNsjvOFcrxPSd","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.006","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Takes a regular expression and returns a plain-English, token-by-token explanation of what it matches.","exampleAgentPrompt":"Can you explain what this regex matches, token by token in plain English: ^([a-zA-Z0-9._%+-]+)@([a-zA-Z0-9.-]+)\\.([a-zA-Z]{2,})$?","exampleUseCases":[{"title":"Decoding an unfamiliar validation regex","prompt":"I found this regex in our codebase and have no idea what it validates — can you explain it token by token in plain English: ^(?=.*[A-Z])(?=.*\\d)(?=.*[@$!%*?&])[A-Za-z\\d@$!%*?&]{8,}$"},{"title":"Learning regex syntax while reviewing a PR","prompt":"There's a regex in this pull request I'm reviewing and I want to understand exactly what it matches before approving — can you walk me through it piece by piece: \\b(https?:\\/\\/)?([\\w-]+\\.)+[\\w-]+(\\/[\\w-./?%&=]*)?\\b"},{"title":"Debugging a regex that's not behaving as expected","prompt":"My regex \\d{1,3}(\\.\\d{1,3}){3} is supposed to match IP addresses but it's matching things it shouldn't — can you explain what each token actually matches so I can figure out what's wrong?"}],"resultDescription":"A plain-English breakdown of the regular expression, explaining each token or group in sequence — describing character classes, quantifiers, anchors, groups, and alternations in human-readable terms so a non-regex expert can understand exactly what the pattern will and will not match.","failureModes":["Invalid or malformed regex syntax may return an error or partial explanation","Extremely long or complex nested patterns may produce truncated output","Regex flavors other than standard (e.g. PCRE vs RE2 specifics) may not be flagged explicitly"],"whenToPreferThis":"Choose this endpoint when a developer, agent, or non-technical user needs to understand what an existing regex pattern matches without running it against test strings. It is ideal for code review, documentation generation, debugging unexpected matches, or onboarding new team members to legacy code. Prefer it over test-based approaches when you want a descriptive explanation rather than just pass/fail results.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:43:29.451Z","isFirstParty":false}