Quiet Tools

Quiet Tools

Small utilities that do one thing. Everything runs in your browser — no account, no upload, no tracking, nothing to install.

Colour contrast checker WCAG 2.1 AA and AAA ratios, plus the nearest passing colour when it fails. EU VAT number validator Format and checksum for all 27 member states, computed offline. JSON ↔ CSV Convert both ways, with nested keys flattened and quoting handled properly. UTM link builder Campaign URLs that stay consistent, with the mistakes flagged as you type. Image compressor Resize and convert to WebP in batch, without uploading anything. Favicon generator Every size a site needs, plus the manifest and the HTML to paste. Cron expression explainer Plain English, the next ten runs, and a warning when it fires every minute. JWT decoder Header, payload and expiry — offline, because a token is a credential. Password generator Real entropy in bits, cryptographic RNG — not a green bar saying "strong". Text diff Longest common subsequence, so an inserted line stays one line. Meta tags & Open Graph Live Google and social previews, with truncation warnings as you type. Unix timestamp converter Both ways, unit detected for you, across timezones. Flags the 2038 limit. Base64 Text, files and data URIs — with UTF-8 handled, where quick versions break. Case converter & slug camelCase to kebab, and slugs that survive accents.

Why they work offline. Each tool is a single HTML page with its logic inside it. Nothing you type is sent anywhere, because there is nowhere for it to be sent — there is no server behind these pages, only static files. You can save any of them and keep using it with the network off.