Developer tools that never see your data
Format JSON, test a regex, decode a JWT, hash a string, convert data formats, diff text or extract an archive: every utility on this page runs in your browser, so what you paste stays on your machine.
That matters more for developers than for anyone else: tokens, connection strings and API payloads routinely end up in online formatters. Here the JWT decoder, the hash generator and the AES encryption tool work entirely client-side, so pasting a production secret does not leak it to a third party.
All 20 tools in this category
- Archive extractor Extract ZIP, RAR, 7z, TAR and GZ archives in your browser. No upload.
- JSON Formatter Format, validate and minify JSON directly in your browser. No upload.
- Base64 Encoder / Decoder Encode or decode Base64, text and files. No upload, 100% local.
- URL Encoder / Decoder Percent-encode or decode URL strings. No upload, 100% local.
- Hash Generator Generate MD5, SHA-1, SHA-256, SHA-512 hashes from text or files. No upload.
- JWT Decoder Decode a JWT (header, payload, expiry) without sending it anywhere. No signature verification.
- Text Diff Compare two texts line by line and see differences highlighted. No upload.
- UUID Generator Generate cryptographically random UUID v4 values. Bulk generation. No upload.
- Case Converter Convert text between camelCase, snake_case, kebab-case, Title Case and more. No upload.
- Text / code viewer Open text and code files that your phone refuses, Markdown, HTML, JSON, CSV, XML and more.
- Regex Tester Test regular expressions against text with highlighted matches and capture groups. No upload.
- Color Converter Convert colors between HEX, RGB, HSL, HSV and CMYK. WCAG contrast checker included. No upload.
- Color Scheme Generator Generate complementary, analogous, triadic, tetradic and monochromatic palettes from a base color. No upload.
- Timestamp Converter Convert Unix epoch timestamps to human dates (UTC + local) and back. Auto-detects seconds vs milliseconds.
- Word Counter Count words, characters, sentences, paragraphs and estimate reading time. Live, no upload.
- Password Generator Generate strong, random passwords with custom rules. Uses crypto.getRandomValues. No upload.
- Lorem Ipsum Generator Generate lorem ipsum placeholder text by paragraphs, sentences or words. Copy in one click. No upload.
- Data Converter Convert data between JSON, YAML and CSV formats. No upload.
- Minify / Beautify Minify or beautify HTML, CSS and JavaScript. No upload.
- AES Encrypt / Decrypt Encrypt or decrypt text using AES-256-GCM. Your passphrase never leaves your browser.
Frequently asked questions
Is it safe to paste tokens or secrets into these tools?
Safer than into most online tools: processing is 100% client-side, so what you paste never leaves your browser. For production secrets, the usual caution still applies; you can verify the no-traffic claim in the network tab.
Do these tools work offline?
Yes. Once a tool page has loaded, it keeps working without a connection, because there is no server doing the work. That is a practical side effect of the no-upload design.
Why is there no API or rate limit?
Because there is no backend to protect: your browser does the computation. Format a 10 MB JSON file at 2 a.m. as often as you like; the only limit is your machine.