jsonversal — free in-browser toolkit

JSON & LLM developer tools that run in your browser.

No signup, no upload, no accounts. Every tool runs 100% on your device — paste JSON, infer schemas, count LLM tokens, and estimate API costs without your data ever leaving your browser.

Explore 69 tools Try JSON Schema Generator

100% local — nothing uploaded 0 sign-up — no accounts Free & unlimited — for devs

Core toolkit

JSON & LLM tools

Format, validate, transform and generate JSON — plus LLM token counting, schema generation and structured output helpers.

Showing 16 of 16 tools

LLM Token & Pricing Calculator

Estimate tokens and cost across GPT, Claude, Llama and Gemini.

Structured Output JSON Schema Generator

Create strict JSON Schema for LLM structured output.

JSON Schema Sample Data Generator

Generate sample JSON that satisfies your schema — mock data in seconds.

JSON to Pydantic Model

Generate Pydantic v2 BaseModel classes from a JSON sample.

JSON to Zod Schema

Infer a Zod validation schema from a JSON sample.

JSON to TypeScript Interface

Generate type-safe TypeScript interfaces from JSON.

JSONPath Tester

Test JSONPath expressions against your JSON and see every match.

JSON Diff

Compare two JSON documents and list every added, removed, changed value.

JSON Formatter & Validator

Pretty-print, validate, and minify JSON — with error line/column hints and document stats.

JSON to Go Struct

Generate Go structs with json tags from a JSON sample.

JSON to C# Class

Generate C# POCO classes with Newtonsoft attributes from JSON.

UUID v7 Generator & Timestamp Decoder

Generate RFC 9562 UUID v7 in bulk and decode the embedded timestamp.

Markdown Editor & Live Preview

Write Markdown and watch the HTML preview render as you type — safely.

Text Diff

Compare two texts with side-by-side and git-style unified diff output.

JSON Escape & Unescape

Escape plain text into a JSON string literal and decode escaped literals.

JSON Sorter & Deduper

Sort object keys and arrays, dedupe items, and pretty-print with stats.