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人気のツール
Uttir で最も使われているツール。クリックですぐに開けます。
JSON Formatter
Format, beautify, and validate JSON with adjustable indentation — instantly in your browser.
Developer Tools
UUID Generator
Generate cryptographically random UUID v4 identifiers, one or a thousand at a time.
Developer Tools
Base64 Encoder
Encode any text — including emoji and non-Latin scripts — into standard Base64.
Developer Tools
JWT Decoder
Decode a JWT’s header and payload and check its expiration — without sending it anywhere.
Developer Tools
JWT Sign (HS256 / RS256)
Sign a JSON Web Token with HS256 (HMAC shared secret) or RS256 (RSA private key). Output is a standard compact JWT (header.payload.signature).
Security Tools
HMAC Generator
Compute a Hash-based Message Authentication Code (HMAC) for any message and shared secret. Supports SHA-256, SHA-512, SHA-1, and MD5. All computation runs in your browser.
Security Tools
Regex Tester
Test and debug regular expressions with live matches, capture groups, and highlighted results.
Developer Tools
Word Counter
Count words, characters, sentences, and paragraphs in your text instantly.
Text Tools
Percentage Calculator
Three percentage tools in one: percent of a value, ratio as a percent, and percent change.
Calculators
最新のツール
最近追加Internet Speed Test
Measure your download speed, latency, and jitter in the browser. Download-only: nothing is uploaded and nothing is tracked.
Network Tools
NewNetwork Latency Test
Ping several well-known endpoints from your browser and compare round-trip times to work out whether a slowdown is you or them.
Network Tools
NewClick Speed Test
Measure your clicks per second (CPS) over 1, 5, 10, or 30 seconds. Works with touch too, and keeps your personal best on this device.
Web Tools
カテゴリから探す
222 ツールが 19 カテゴリに分類されています。カテゴリを選んで、中身をすべてご覧ください。
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What Is My IP Address — And What Does It Reveal About Me?
Your IP address is a public identifier that any website you visit can see. Learn what it exposes (city, ISP, ASN, sometimes a VPN), what it does not expose, and how to check yours without uploading anything.
2026年8月31日 · 7 分で読めます
How to Create an XML Sitemap (and Why You Need One)
A sitemap.xml file tells search engines which pages on your site exist. Learn what to include, what to leave out, how to write one by hand or generate one, and how to submit it to Google and Bing.
2026年8月31日 · 7 分で読めます
How to Test Color Contrast for Accessibility (WCAG 2.2 Explained)
Color contrast is the most-measured accessibility metric on the web. This guide explains the WCAG 2.2 contrast formula, the AA and AAA thresholds, and how to make sure your site is usable for people with low vision.
2026年8月31日 · 6 分で読めます
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