# About ZeroTool

> Free online developer tools. No sign-up. Each tool explains how it processes input and any requests to other services.

ZeroTool (https://zerotool.dev) has 141 free developer tools. Each tool is one web page; there is no account and no API.

- Tool pages are at https://zerotool.dev/tools/{slug}/ in English and at /zh/tools/{slug}/, /ja/tools/{slug}/ and /ko/tools/{slug}/ in Chinese, Japanese and Korean. The same tools are listed with their names in those languages in the files under "Other languages".
- The tools process the text, files and keys you give them with JavaScript in your browser tab and do not upload them.
- These tools send requests because of what they do:
  - [DNS Lookup](https://zerotool.dev/tools/dns-lookup/): Lookups send the domain name to the DNS resolver you pick (Cloudflare or Google).
  - [QR Code Reader](https://zerotool.dev/tools/qr-code-decoder/): Images and camera frames are decoded on this page; URL mode requests the image from the host at the address you enter.
  - [Markdown Preview](https://zerotool.dev/tools/markdown-preview/): Markdown is rendered on this page; web images load from their URLs, and the image hosts receive those requests.
  - [Meta Tag Generator](https://zerotool.dev/tools/meta-tag-generator/): Tags are generated on this page; Facebook, Twitter and Discord previews request the image URLs you enter from their hosts.
- This tool uses the network only after you turn on an option:
  - [Markdown to Word Converter](https://zerotool.dev/tools/markdown-to-word/): export downloads http(s) images from their hosts only when Embed web images is enabled.
- Most pages load Google Analytics 4 (page views, and tool-use events that record the tool name and action, not your input) and Google AdSense. Pages for tools that handle credentials, keys, tokens, or private files and text load neither: [AES Encryption & Decryption](https://zerotool.dev/tools/aes-encrypt-decrypt/), [Basic Auth Header Generator](https://zerotool.dev/tools/basic-auth-header-generator/), [Bcrypt Generator & Checker](https://zerotool.dev/tools/bcrypt-generator/), [Cookie Parser & Decoder](https://zerotool.dev/tools/cookie-parser/), [CSR Decoder](https://zerotool.dev/tools/csr-decoder/), [cURL to Code Converter](https://zerotool.dev/tools/curl-to-code/), [Docker Run to Compose](https://zerotool.dev/tools/docker-to-compose/), [Env File Parser](https://zerotool.dev/tools/env-file-parser/), [EXIF Metadata Viewer](https://zerotool.dev/tools/exif-metadata-viewer/), [File Hash Checker](https://zerotool.dev/tools/file-hash-checker/), [HAR Analyzer & Viewer](https://zerotool.dev/tools/har-file-analyzer/), [Hash Generator](https://zerotool.dev/tools/hash-generator/), [HMAC SHA256 Generator](https://zerotool.dev/tools/hmac-generator/), [htpasswd Generator](https://zerotool.dev/tools/htpasswd-generator/), [HTTP Header Analyzer](https://zerotool.dev/tools/http-header-analyzer/), [IBAN Validator & Parser](https://zerotool.dev/tools/iban-validator-parser/), [Image Compressor](https://zerotool.dev/tools/image-compressor/), [JWT Decoder](https://zerotool.dev/tools/jwt-decoder/), [JWT Generator / Signer](https://zerotool.dev/tools/jwt-generator/), [Password Generator](https://zerotool.dev/tools/password-generator/), [Pixelate Image](https://zerotool.dev/tools/pixelate-image/), [PKCE Generator](https://zerotool.dev/tools/pkce-generator/), [RSA Key Pair Generator](https://zerotool.dev/tools/rsa-key-generator/), [Redact API Keys & Secrets](https://zerotool.dev/tools/secret-redactor/), [SQLite Viewer](https://zerotool.dev/tools/sqlite-viewer/), [TOTP Generator](https://zerotool.dev/tools/totp-generator/), [WiFi QR Code Generator](https://zerotool.dev/tools/wifi-qr-code-generator/), [Invisible Character Detector](https://zerotool.dev/tools/zero-width-character-detector/).
- Source code: https://github.com/kassol/zerotool-dev

Some tools save your latest input or settings in localStorage. Each tool's privacy section explains what is saved and how to clear it. The sensitive tool pages listed above save neither input nor settings.

The footer links to AI services open a fixed question about ZeroTool with public site URLs. They do not include tool input. The destination service controls its responses and may require sign-in.

## AI assistant resources

- [llms.txt](https://zerotool.dev/llms.txt): Tool names, descriptions and network use
- [llms-full.txt](https://zerotool.dev/llms-full.txt): Full tool reference and usage steps (English)
- [index.md](https://zerotool.dev/index.md): Site overview and resource index
- [categories.md](https://zerotool.dev/categories.md): All tools by category

## Public pages

- [Home](https://zerotool.dev/)
- [Tools](https://zerotool.dev/tools/)
- [Blog](https://zerotool.dev/blog/)
- [About](https://zerotool.dev/about/)
- [Privacy](https://zerotool.dev/privacy/)
- [Terms](https://zerotool.dev/terms/)
- [Contact](https://zerotool.dev/contact/)
- [Source on GitHub](https://github.com/kassol/zerotool-dev)