JSON to TypeScript — Generate Interfaces Online

Paste JSON and get TypeScript interface or type definitions. Choose root name, interface vs type alias, and optional properties — all processing stays in your browser.

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JSON to TypeScript — generate interfaces from samples
Turn API fixtures and config exports into compilable-looking TypeScript definitions. Distinct from JSON formatter (whitespace) and validator (syntax).

Developer notes

• Root must be a JSON object or array. • Optional properties add `?` to fields — review before publishing shared types. • Type aliases vs interfaces follow your selected option. • Validate source JSON first when payloads are untrusted.

When teams use JSON → TypeScript

• Bootstrap SDK types from example API responses. • Document config shapes for Rust/Python teams sharing JSON fixtures. • Quick prototypes before adopting schema-first tooling.

Examples

User object

Sample JSON

{ "user": { "id": 42, "name": "Ada Lovelace", "active": true }, "address": { "street": "10 Downing St", "city": "London", "postcode": "SW1A 2AA" } }

Generated TypeScript

interface RootObject { user: User; address: Address; } interface Address { street: string; city: string; postcode: string; } interface User { id: number; name: string; active: boolean; }

Nested payload

Sample JSON

{ "user": { "email": "[email protected]" } }

Generated TypeScript

Nested `user` object with `email: string` field.

Navigate related JSON tools

Browse the JSON tools hub. Validate with the JSON validator, prettify via the JSON formatter, or repair broken syntax with JSON repair.

JSON to TypeScript FAQ

Type generation, not validation

Does this validate JSON?

Invalid JSON errors before generation — use the JSON validator for detailed diagnostics.

Union types for mixed arrays?

json-to-ts infers unions when array items differ — review output manually.

Server uploads?

Never — conversion runs locally after dynamic import.

JSON Tools

Validate, format, diff and explore JSON payloads — complementary to minifiers and converters.

Explore other tool categories

Minify

Shrink code and assets for production — minify JavaScript, CSS, HTML, JSON and XML before gzip or CDN deploy.

Beautify

Make code readable with consistent indentation — beautify JavaScript, CSS, TypeScript, SCSS, LESS, Markdown, GraphQL, SQL, YAML and more in your browser.

Unminify

Expand minified or compressed code — unminify JavaScript, CSS, TypeScript, SCSS, LESS, SQL, YAML and other formats when debugging or reviewing.

Conversion

Transform data between JSON, YAML, XML and CSV locally — no server uploads.

CSS preprocessors

Compile SCSS or LESS to standard CSS in the browser — pair with beautify or minify for a full stylesheet workflow.

SVG Tools

Preview, optimize with SVGO, export Data URI, resize, beautify, convert to JSX and validate SVG — all in your browser.

DevOps & Infra

Terraform HCL format/validate/minify, Dockerfile format & lint, Docker Compose and .env validation.

CI/CD

GitHub Actions and GitLab CI — format YAML and check workflow/job structure in your browser.

Logs & observability

Line-oriented JSON/NDJSON and Nginx/Apache access logs — format, filter, validate, and CSV/TSV.

Kubernetes

Multi-doc manifests, structural validate, Ingress/Deployment starters, and Helm values formatting.

Networking / IP

CIDR, subnets, and IPv4/IPv6 helpers — in your browser.

Security & tokens

JWKS, X.509 certificates, and secrets scan — browser-local.

API & schemas

OpenAPI tools to format, validate, and lint your specs.

Encoding

Encode or decode Base64, URL components and HTML entities — client-side only.

Developer utilities

Timestamps, UUID, ULID, Nanoid, cron, passwords, regex, slugify, number bases, case, text diff, and chmod — all client-side.

Text & Markdown

Count words, build Markdown TOCs, and clean line lists — all in your browser.

AI & LLM

Token counting, pricing estimates, and context-window fit — 100% browser-local.

Serialization

Serialize and deserialize PHP data structures beside JSON workflows.