About JSON Toolbox

JSON Toolbox is a collection of free developer tools for working with JSON: format conversion, code generation, JSONL inspection, and JSON Schema validation.

Every tool runs entirely in your browser. There is no backend, no upload, no account. Your data — API payloads, database exports, ML datasets — never leaves your machine. This is a deliberate design decision: most online converters send your data to a server for processing. We think developers should not have to trust anyone with their data just to convert a file.

The tools are built for real-world data: arrays with inconsistent fields, nulls mixed with values, nested objects several levels deep. Type inference merges every sample you paste to produce accurate optional/nullable information in the generated output.