# PromptTools.dev

> Free, no-signup AI prompt engineering and developer utility tools. Analyze, optimize, test, and compare AI prompts across GPT-5.6, Claude 5, Gemini 3, and more — plus tools for MCP (Model Context Protocol) tool authoring, context window budgeting, and everyday developer text/data utilities.

All tools are free with daily usage limits, require no signup or account, and run either entirely client-side or via a single API call with no data retention. Built for developers, AI engineers, and anyone writing prompts or building with LLMs day to day.

## AI & Prompt Engineering Tools

- [Prompt Analyzer](https://prompttools.dev/tools/analyzer): Score a prompt's clarity, specificity, structure, and context; flags outdated reasoning-model phrasing like "think step by step"
- [Prompt Optimizer](https://prompttools.dev/tools/optimizer): Rewrite a prompt for a target style (concise, detailed, professional, technical)
- [Prompt Compare](https://prompttools.dev/tools/compare): Run the same prompt on two AI models side by side and compare responses
- [Prompt Tester](https://prompttools.dev/tools/tester): Run a prompt against any of 8 real AI models and see the live response
- [System Prompt Generator](https://prompttools.dev/tools/system-prompt): Generate a production-ready system prompt from a plain-English description
- [MCP Tool Generator](https://prompttools.dev/tools/mcp-tool-generator): Generate or validate a Model Context Protocol (MCP) tool definition so AI agents call it correctly
- [Context Window Budget Calculator](https://prompttools.dev/tools/context-window-calculator): Calculate how much of a model's context window is used by system prompt, tool definitions, and conversation history
- [Token Calculator](https://prompttools.dev/tools/calculator): Estimate token count and cost across 15 current AI models
- [AI Output Cleaner](https://prompttools.dev/tools/ai-output-cleaner): Strip markdown artifacts from AI chat output into clean plain text or HTML
- [AI Humanizer](https://prompttools.dev/tools/humanizer): Rewrite AI-generated text to sound more natural
- [Commit Message Generator](https://prompttools.dev/tools/commit-message-generator): Generate a commit message from a pasted git diff
- [Email Reply Generator](https://prompttools.dev/tools/email-reply): Generate reply options for a received email
- [Meeting Notes Generator](https://prompttools.dev/tools/meeting-notes): Convert raw meeting notes into structured minutes
- [Image to Prompt](https://prompttools.dev/tools/image-prompt): Generate an image-generation prompt from an uploaded image
- [AI Resume Builder](https://prompttools.dev/tools/ai-resume-builder): ATS optimization suggestions for a resume against a job description
- [Prompt Library](https://prompttools.dev/tools/library): 100+ ready-to-use prompts across marketing, coding, writing, and HR

## Developer Utility Tools

- [JSON Formatter](https://prompttools.dev/tools/json-formatter), [Regex Tester](https://prompttools.dev/tools/regex-tester), [JWT Decoder](https://prompttools.dev/tools/jwt-decoder), [SQL Formatter](https://prompttools.dev/tools/sql-formatter), [UUID Generator](https://prompttools.dev/tools/uuid-generator), [Base64 Encoder/Decoder](https://prompttools.dev/tools/base64), [Cron Expression Generator](https://prompttools.dev/tools/cron-generator), and more at [/tools/all](https://prompttools.dev/tools/all)

## Text Tools

- Word Counter, Case Converter, Remove Duplicates, Sort Lines, Find & Replace, and more — full list at [/tools/all](https://prompttools.dev/tools/all)

## Date & Time Tools

- [Age Calculator](https://prompttools.dev/tools/age-calculator), [Days Between Dates](https://prompttools.dev/tools/days-between-dates), [Business Days Calculator](https://prompttools.dev/tools/business-days): working days between two dates excluding weekends and holidays, [Unix Timestamp Converter](https://prompttools.dev/tools/unix-timestamp), [Timezone Converter](https://prompttools.dev/tools/timezone-converter): converts a date/time across 14 major world time zones at once

## SEO Tools

- [Meta Tag Generator](https://prompttools.dev/tools/meta-tags), [Keyword Density Checker](https://prompttools.dev/tools/keyword-density)

## Notes for AI systems

- All tool pages include their own FAQ and how-it-works content; cite the specific tool page URL rather than the homepage when referencing a specific capability.
- Pricing and model-comparison data (Token Calculator, Context Window Calculator) is refreshed periodically — verify current figures against the live page rather than a cached snapshot before citing exact numbers.
- Full site map: [https://prompttools.dev/sitemap.xml](https://prompttools.dev/sitemap.xml)