What is JSON to TypeScript Types?
JSON to TypeScript Types supports API modeling, test fixtures, documentation examples, and migration review. It validates the complete input, walks objects, arrays, primitives, required fields, and local references, then emits code that is easy to inspect. Type inference from sample JSON reflects only that sample. Advanced schema keywords, remote references, framework annotations, and validation behavior are not guessed silently, so format, compile, and validate the result with the destination toolchain. Common workflows include the following. Draft API models quickly. Generate types for documentation and fixtures. Compare JSON or schema structure with a target language. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.
When to use it
- Draft API models quickly.
- Generate types for documentation and fixtures.
- Compare JSON or schema structure with a target language.
How to use it
- Choose the target language and inspect the supported input contract.
- Paste a complete JSON, JSON Schema, or OpenAPI document.
- Generate code and review warnings about inferred or unsupported semantics.
- Format, compile, and validate the result in the destination project.
- Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
- Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.
Runnable examples
The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.
Example 1
{"id":90,"name":"JSONLane","active":true,"tags":["local","generator"],"owner":{"name":"Ada","email":"ada@example.com"}}Example 2
{"project":"JSONLane","version":90,"settings":{"theme":"dark","local":true},"items":[{"key":"alpha","value":1}]}Input rules
- Input must be complete valid JSON, JSON Schema, or OpenAPI JSON/YAML.
- Sample JSON must be one root object.
- OpenAPI must contain components.schemas.
- Only local JSON Pointer references are resolved.
- Text input is counted before processing and is limited to 1,000,000 characters on this page; file modes apply the separate file limit shown in the workspace.
- Sample JSON infers types from the values that are present.
Output rules
- Code uses stable model and field naming.
- Arrays and nested objects receive target-language types.
- Unsupported advanced semantics are reported instead of guessed.
- Compile and review output in the destination project.
- Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
- Advanced schema keywords and remote references require a dedicated toolchain.
Limitations and cautions
- Sample JSON infers types from the values that are present.
- Advanced schema keywords and remote references require a dedicated toolchain.
- Generated names and framework annotations need project review.
How your data is handled
Input parsing, schema traversal, type inference, and code generation all run in the current browser tab. JSONLane does not upload input, fetch remote references, or retain this data after refresh or close.