quicktype

Input—per 1M tokens

Output—per 1M tokens

Context—tokens

WeightsClosed

About

quicktype infers data types and generates models, serializers, and validators in more than 25 languages. Inputs include sample JSON, API URLs, JSON Schema, TypeScript, and GraphQL queries. It can identify optional or nullable fields, numeric types, dates, UUIDs, enums, unions, maps, and nested or equivalent structures. Generated code can read, write, and validate data in a target language. The browser app lets users paste JSON and generate code; the project says it works offline without sending sample data over the Internet. A CLI processes files, URLs, directories of samples, or standard input, making it usable in build pipelines, CI jobs, or git hooks. A hosted MCP endpoint connects to Claude Code, Cursor, Codex, or other MCP clients without an API key. The open-source project uses the Apache-2.0 license, and its web app and CLI are free. The CLI and Node.js packages require Node.js 20 or newer. The site describes generated types as a way to help teams build API clients, catch API changes, and provide IDEs and AI agents with typed data models.

Who it is for

quicktype suits developers and teams generating typed models from data for API clients, or aiming to catch API changes. Its CLI and MCP endpoint also fit build workflows and MCP-client use.

What is good

Generates code in more than 25 languages
Accepts JSON, schemas, API URLs, and GraphQL queries
Browser app works offline without sending sample data
Hosted MCP endpoint needs no API key

What to know first

CLI and Node.js packages require Node.js 20 or newer

Verdict

quicktype offers browser and CLI workflows for turning structured inputs into types and related code, with an MCP connection option. Its offline browser app and Apache-2.0 license are relevant for teams weighing data handling and openness.

Compared on code generators

Free plan: Yesquicktype.io
Project scaffolding: Noquicktype.io
Schema-to-code generation: Yesquicktype.io
CLI available: Yesquicktype.io
IDE plugins: Yesquicktype.io
Supported languages: C, C#, C++, Crystal, Dart, Effect Schema, Elixir, Elm, Flow, Go, GraphQL, Haskell, Java, JavaScript, JSON Schema, Kotlin, Objective-C, PHP, Pike, Python, Ruby, Rust, Scala, Smithy, Swift, TypeScript, Zodquicktype.io

Facts

Purpose: quicktype infers types from JSON and generates models, serializers, and validators in more than 25 languages.quicktype.io · 30 Sept 2026
Inputs: It accepts sample JSON, API URLs, JSON Schema, and GraphQL queries.quicktype.io · 30 Sept 2026
Inference: It can infer nullability, optional fields, numeric types, dates, UUIDs, enums, unions, maps, and nested type names.quicktype.io · 30 Sept 2026
Code output: Generated output can include serializers and runtime validation code along with types.quicktype.io · 30 Sept 2026
Browser use: The product offers a browser app for pasting JSON and generating code.quicktype.io · 30 Sept 2026
CLI: The CLI can generate code from files, URLs, or standard input and can be used in a build pipeline, CI job, or git hook.quicktype.io · 30 Sept 2026
MCP integration: A hosted MCP endpoint connects quicktype to Claude Code, Cursor, Codex, or any MCP client without an API key.quicktype.io · 30 Sept 2026
MCP endpoint: The MCP server URL is https://mcp.quicktype.io/mcp.mcp.quicktype.io · 30 Sept 2026
Open source: The GitHub repository identifies quicktype as open source under the Apache-2.0 license.github.com · 30 Sept 2026
Offline and privacy: The GitHub README says the web app works offline and does not send sample data over the Internet.github.com · 30 Sept 2026
CLI requirement: The CLI and Node.js packages require Node.js 20 or newer.github.com · 30 Sept 2026
Who it serves: The site describes using generated types to help teams build API clients, catch API changes, and give IDEs and AI agents a typed model of data.quicktype.io · 30 Sept 2026
What it does: quicktype infers types from JSON and generates models, serializers, and validators in more than 25 languages.quicktype.io · 30 Sept 2026
Supported inputs: quicktype accepts sample JSON, API URLs, JSON Schema, TypeScript, and GraphQL queries.github.com · 30 Sept 2026
Inference capabilities: quicktype detects enums, dates, UUIDs, numeric types, nullable properties, unions, maps, and equivalent structures.quicktype.io · 30 Sept 2026
Generated serialization: quicktype generates code to read, write, and validate data in the target language.quicktype.io · 30 Sept 2026
Command line: The CLI can generate code from files, URLs, directories of samples, or standard input.quicktype.io · 30 Sept 2026
Browser privacy: The web app works offline and does not send sample data over the Internet.github.com · 30 Sept 2026
Runtime requirement: The quicktype CLI and Node.js packages require Node.js 20 or newer.github.com · 30 Sept 2026
Community support: The project directs users to a quicktype Slack community for help and discussion.github.com · 30 Sept 2026
Usage scale: The official site says millions of developers have generated billions of lines of code with quicktype.quicktype.io · 30 Sept 2026
Contributors: The official site says more than 200 contributors have contributed to the open source project.quicktype.io · 30 Sept 2026