# HandyToolsBox

> Free online developer, SEO, AI, text, design, PDF, and productivity tools running 100% in the browser. No signup, zero tracking, instant execution.

HandyToolsBox (https://handytoolsbox.com) provides 30+ browser-side web utilities for developers, SEO specialists, writers, digital marketers, and productivity enthusiasts. All processing happens locally in client-side JavaScript memory, guaranteeing complete data privacy and sub-millisecond performance.

## Tool Categories

- [AI & Productivity Tools](https://handytoolsbox.com/tool-category/online-ai-productivity-tools): Free AI prompt token counters, prompt length estimators, readability heatmaps, timezone meeting planners, and cron job generators.
- [Developer & Code Tools](https://handytoolsbox.com/tool-category/online-developer-tools): JSON formatters, validators, CSV-to-JSON converters, Base64 encoder/decoders, and code formatting utilities.
- [SEO & Marketing Tools](https://handytoolsbox.com/tool-category/online-seo-tools): Meta tag generators, robots.txt generators, XML sitemap builders, keyword density checkers, and Google SERP preview tools.
- [Text & Writing Tools](https://handytoolsbox.com/tool-category/online-text-tools): Word & character counters, case converters, duplicate line removers, and text formatting tools.
- [Image & Design Tools](https://handytoolsbox.com/tool-category/online-image-tools): Image compression, format conversion (PNG, JPG, WebP), color palette generators, and CSS utilities.
- [PDF & Document Tools](https://handytoolsbox.com/tool-category/online-file-tools): Merge, split, compress, and convert PDF documents in browser.
- [Calculators & Unit Converters](https://handytoolsbox.com/tool-category/online-calculators): Scientific calculators, unit converters, PX to REM converters, and date/time tools.
- [Security & Privacy Tools](https://handytoolsbox.com/tool-category/online-security-tools): Password generators, MD5/SHA256 hash generators, and UUID generators.

## Essential Free Tools

- [AI Prompt Token Estimator](https://handytoolsbox.com/tools/ai-prompt-token-estimator): Estimate token counts for ChatGPT, Claude, and Gemini prompts to optimize LLM API costs.
- [JSON Formatter & Validator](https://handytoolsbox.com/tools/json-formatter-validator): Pretty print, validate, repair, and format JSON string payloads locally in your browser.
- [Robots.txt Generator](https://handytoolsbox.com/tools/robots-txt-generator): Generate syntax-perfect robots.txt files for Googlebot, Bingbot, and AI search crawlers.
- [Word & Character Counter](https://handytoolsbox.com/tools/word-character-counter): Real-time word, character, sentence, paragraph, and reading time counter with readability stats.
- [PX to REM Converter](https://handytoolsbox.com/tools/px-to-rem-converter): Convert pixel values to CSS rem/em units with customizable base font sizes.
- [CSV to JSON Converter](https://handytoolsbox.com/tools/csv-to-json-converter): Convert raw CSV spreadsheet data into structured JSON objects.
- [Meta Tag Generator](https://handytoolsbox.com/tools/meta-tag-generator): Create SEO title, meta description, Open Graph, and Twitter Card head tags.

## Machine & API Resources

- [Tools Directory API](https://handytoolsbox.com/api/tools): Public JSON endpoint listing active tools, descriptions, categories, and direct URLs.
- [Sitemap Index](https://handytoolsbox.com/sitemap_index.xml): XML sitemap listing all crawlable pages for search engine and AI indexing.

## Optional

- [Full Catalog LLM Guide](https://handytoolsbox.com/llms-full.txt): Complete detailed text reference of all tools, features, FAQs, and schemas for LLMs.