What is JSON?

JSON (JavaScript Object Notation) is a text-based data interchange format built from objects, arrays, strings, numbers, booleans and null. It is specified by RFC 8259 and ECMA-404.

Primary sources

Specifications cited by the tools below whose own titles define JSON.

20 tools that work with JSON

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Text Tools2

String Escaper & UnescaperEscape strings for JSON, JavaScript, CSV, SQL, XML or shell — and unescape them again.Wrap Lines in Quotes or BracketsAdd a prefix and suffix to every line and join them — build SQL IN lists, arrays and CSV rows.

Data & Format Tools11

.env to JSON ConverterConvert .env files to JSON and back — for config migrations and CI variables.CSV Column ExtractorPull selected columns out of a CSV by name or position, and reorder them.Data Format ConverterConvert between JSON, YAML, XML, CSV, TSV and TOML in any direction, locally in your browser.JSON DiffCompare two JSON documents and see exactly which keys were added, removed or changed.JSON FlattenerFlatten deeply nested JSON into dot-notation keys, or expand flat keys back into nested objects.JSON Formatter & ValidatorFormat, validate, repair and analyse JSON — with errors that point at the exact line.JSON Key SorterSort object keys and arrays in a JSON document to make two versions comparable.JSON MergeDeep-merge several JSON documents, choosing how arrays and conflicts are resolved.JSON to TypeScript ConverterGenerate TypeScript interfaces, Zod schemas, Go structs, Python dataclasses or Rust structs from JSON.JSON ValidatorCheck whether JSON is valid, with the precise position of the error and what usually causes it.JSONPath TesterRun JSONPath expressions against a document and see the matches instantly.

PDF Tools1

PDF to JSON ConverterExport a PDF as JSON — both the recovered document structure and the raw line geometry.

Samples & Mock Data4

Mock Data GeneratorGenerate realistic fake test data in 14 formats from 100+ field types, with reproducible seeds.Sample Dataset GeneratorDownload ready-made sample datasets — users, orders, products, transactions — as CSV, JSON, SQL or Excel-ready TSV.Sample File GeneratorCreate valid test files of an exact size in 22 formats — text, data, code, images, audio, PDF and ZIP.Sample JSON GeneratorTurn a JSON Schema into realistic sample documents, respecting types, enums, formats and constraints.

AI & LLM Tools2

Chat Export FormatterDrop in an exported conversations file and get clean Markdown, HTML or plain text — one document per conversation.JSONL ValidatorValidate JSON Lines line by line, check chat-format structure, and estimate what training on the file would cost.

Related terms

Terms that appear alongside JSON on the same tools.

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