10 free tools · no sign-up

The AI dev tools you keep Googling for.

Token counters, prompt analyzers, schema converters, cost calculators — single-purpose, free, and entirely in-browser. Built for prompt engineers, LLM builders, and indie AI developers.

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LLM Token Counter

Live

Count tokens for Claude, GPT-4, and Gemini side-by-side with live cost estimates.

claudegptgeminicostclient-side

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JSON Schema → Claude Tool

Coming soon

Convert any JSON Schema into a ready-to-use Anthropic tool-use definition.

claudetool-usejson-schemaclient-side

Cron Expression Explainer

Coming soon

Cron ↔ English in both directions. Validates schedules. No sign-up.

cronschedulingclient-side

Prompt Diff Tool

Coming soon

Compare two prompt versions structurally. See exactly what changed.

promptsdiffclient-side

Markdown → Anthropic Messages API

Coming soon

Paste a conversation in markdown. Get the exact API request JSON Claude expects.

claudeapiclient-side

Claude System Prompt Analyzer

Coming soon

Paste your system prompt. Get clarity + length + structure feedback.

claudepromptsauditai-powered

Regex Builder from Natural Language

Coming soon

Describe what you want to match. Get a regex with examples and edge-case tests.

regexai-powered

JSON Validator + AI Fixer

Coming soon

Paste broken JSON. Get validation errors + an AI-suggested fix.

jsonai-powered

AI Cost Calculator

Coming soon

Project monthly LLM API costs across Claude, GPT, and Gemini.

costpricingclient-side

Prompt Template Extractor

Coming soon

Paste a long prompt with variables. Get a clean reusable template.

promptstemplatesai-powered