# Free Developer Tools | Alher Tech

> 15+ free online tools for developers: JSON formatter, Base64, UUID, JWT, hash, URL encoder, password, regex, color picker, cron and more. 100% client-side.

- Canonical page: https://alhertech.com/en/tools/
- Site: Alher Tech (custom software, AI agents and SEO engineering, https://alhertech.com/)
- Contact: https://alhertech.com/en/contact/

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15+ free online tools for developers: JSON formatter, Base64, UUID, JWT, hash, password generator, regex tester, LLM cost calculator and more. 100% client-side: your data never leaves the browser.

- [JSON Formatter & Validator](https://alhertech.com/en/json-formatter/)
Format, validate, and minify JSON instantly. Free, fast, and 100% client-side.

- [Base64 Encoder & Decoder](https://alhertech.com/en/base64-encoder/)
Encode text to Base64 or decode Base64 back to text. Supports UTF-8, URL-safe mode, and file encoding.

- [UUID Generator](https://alhertech.com/en/uuid-generator/)
Generate cryptographically secure UUIDs (v4) in bulk. Copy or export as CSV / JSON.

- [JWT Decoder & Inspector](https://alhertech.com/en/jwt-decoder/)
Decode and inspect JSON Web Tokens. View header, payload, and expiration. No tokens ever leave your browser.

- [Hash Generator](https://alhertech.com/en/hash-generator/)
Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes instantly. Useful for integrity checks and content fingerprinting.

- [URL Encoder & Decoder](https://alhertech.com/en/url-encoder/)
Percent-encode and decode URL components. Handles UTF-8 and reserved characters correctly.

- [Unix Timestamp Converter](https://alhertech.com/en/unix-timestamp-converter/)
Convert Unix timestamps to human-readable dates and back. Supports seconds, milliseconds, and multiple timezones.

- [Password Generator](https://alhertech.com/en/password-generator/)
Generate strong, random passwords using your browser's cryptographic RNG. Fully customizable length and character sets.

- [Lorem Ipsum Generator](https://alhertech.com/en/lorem-ipsum-generator/)
Generate placeholder text, paragraphs, sentences, or words. Classic Lorem Ipsum for design mockups and prototypes.

- [SQL Formatter](https://alhertech.com/en/sql-formatter/)
Format and beautify SQL queries instantly. Keywords uppercased, predictable indentation, multi-dialect syntax.

- [Regex Tester](https://alhertech.com/en/regex-tester/)
Test JavaScript regular expressions live. Highlights matches, captures, and shows errors as you type.

- [Color Picker & Converter](https://alhertech.com/en/color-picker/)
Pick colors and convert between HEX, RGB, HSL and OKLCH. WCAG contrast checker included.

- [Meta Tags Previewer](https://alhertech.com/en/meta-tags-previewer/)
Preview how your page appears on Google, Twitter/X, Facebook, LinkedIn and WhatsApp. Spots missing Open Graph and Twitter Card tags.

- [Cron Expression Generator](https://alhertech.com/en/cron-expression-generator/)
Build and decode cron expressions visually. See the next scheduled executions in your timezone.

- [YAML ↔ JSON Converter](https://alhertech.com/en/yaml-to-json-converter/)
Convert YAML to JSON and back instantly. Validate YAML syntax and pretty-print JSON output.

- [LLM API Cost Calculator](https://alhertech.com/en/llm-cost-calculator/)
Estimate your monthly bill for Claude, GPT, Gemini, DeepSeek and 40+ AI models from your real token usage. Free and 100% client-side.