Developer Tools

Free, browser-based utilities for AI development, JSON, text, encoding, and more. 8 tools — all run in your browser.

Prompt Tools

3 tools

Token counters, cost calculators, and context window analyzers for LLM prompts.

Count tokens in your prompts for GPT-4, Claude, Llama, and other AI models.

Estimate API costs for your prompts across major AI providers and models.

Check if your content fits within the context window of different AI models.

2 tools

JSON Schema generators, AI output schema builders, and validation utilities.

Generate valid JSON Schema from sample JSON data instantly.

Generate structured output schemas for AI model responses and function calls.

2 tools

OpenAPI validators, spec converters, and REST API tooling.

Validate OpenAPI 3.x specifications against the official schema.

Convert OpenAPI specifications to Model Context Protocol tool definitions.

1 tool

Model Context Protocol tool schema validators and server configuration helpers.

Validate Model Context Protocol tool schemas and server configurations.

Tell us what you need — we build based on requests.