Tools
Turn any JSON payload into TypeScript interfaces, Zod schemas, or 8 other languages, inferred live.
Paste any JSON and get TypeScript interfaces, a Zod schema, or code for Go, Python, Rust, C#, Java, Kotlin and Swift — inferred live as you type. Optional fields, nullable values and unions are detected automatically. Runs entirely in your browser, nothing is uploaded.
Paste JSON to generate types
Writing types for an API response by hand is slow and easy to get wrong, especially when fields are sometimes missing or null. This tool builds an intermediate type model from your actual JSON, merging every item in an array to work out which fields are optional, which are nullable, and which mix types. From that model it can render a TypeScript interface or type, a Zod schema with an inferred type, or code for eight other languages, each with that language's own naming conventions and rename annotations.
Paste or type JSON and the type definitions update automatically, debounced so large payloads never stutter.
Toggle between a TypeScript interface/type and a runtime Zod schema with an inferred type export.
Go, Python (Pydantic or dataclass), Rust, C#, Java, Kotlin and Swift, each with idiomatic naming and rename annotations.
Invalid JSON shows the exact line and column, while the last valid output stays visible, dimmed, underneath.
Keys missing from some array items become optional, mixed types become unions, and null values become nullable.
Copy the generated code or download it with the right file extension for your chosen language.
Paste JSON, load a sample, or upload a .json file.
Nested objects, optional fields and unions are inferred live.
Toggle between a TypeScript interface/type and a Zod schema.
Open More languages for Go, Python, Rust, C#, Java, Kotlin or Swift.
Grab the generated code, or download it with the right file extension.
Parsing and type generation run entirely in your browser. Your JSON is never sent to a server, and only your chosen options are remembered locally.
Free online tool to format, beautify, and validate JSON. Features include syntax highlighting, minification, error detection, and customizable indentation. No signup required, 100% private - all processing happens in your browser.
Test regular expressions against your own text with live match highlighting, per-match capture groups and a token-by-token explain panel. Switch to replace mode to preview substitutions, or load a ready-made pattern from the library. Everything runs in your browser so nothing is uploaded.
Decode JWT tokens free online. View header, payload, and signature. Check expiration timestamps. Perfect for debugging authentication issues.
Developed by MadMVP
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