RFS — Regex From Selection

A Chrome extension that proposes multiple regex candidates at varying abstraction levels from text you select in the browser. ■ Highlights ・72 built-in detectors: email / URL / credit card / Japanese address / price / phone / UUID / GitHub token / JWT / dates / postal code / etc. Recognize known patterns instantly. ・Top-down generalization algorithm: even unknown patterns get parallel candidates at varying abstraction (character class, length). ・3-axis tuning: intent × domain × dialect - intent: filter / extract / validate / replace / security / redact - domain: spoiler / sns-ngword / forum-mod / data-extract / code-review - dialect: JavaScript / Python / Java / Ruby / Go / PCRE / PostgreSQL / MySQL / BigQuery / YARA / HTML5 and more ・Quality scoring ranks candidates; the top pick is marked "Recommended". ・Inline tester: edit and verify the regex without leaving the popover. ・Switchable UI (Japanese / English). ■ How to use 1. Select any text on a page 2. Right-click → "Generate regex" (or press Alt+R) 3. The popover shows candidates ordered by quality 4. Click "Copy" on the one you want, or open "Tester" to fine-tune ■ About AI (Gemini Nano) You can opt-in to use Chrome's built-in language model (Gemini Nano) for extra candidates. The AI layer is supplementary — the algorithm and the 72 detectors are designed to be useful on their own. Nano requires Chrome 128+ with chrome://flags enabled and a model download (~2 GB). Setup instructions are provided on the options page. ■ Privacy Fully local. Selected text, generated regex, and any other data never leave your device. Even with AI enabled, processing happens inside Chrome's built-in Gemini Nano (on-device). See the privacy policy for details.