JSON to Java Converter
Convert JSON to Java POJO classes for Java development
JSON Input
Java Output
What Is JSON to Ruby?
Ruby uses hashes and OpenStruct for dynamic JSON access. For typed access and clearer structure, you can use classes or structs. This tool generates Ruby classes from your JSON structure so you can parse API responses with JSON.parse and map to typed objects. The JSON specification defines the input format.
Conversion runs in your browser. Set the class name in the config. Nothing is sent to a server. The generated classes work with Rails, Sinatra, or plain Ruby projects.
How to Use This Tool
Paste or Upload JSON
Paste your JSON into the left editor or upload a file. Use the config panel to set the root Class Name. The more representative your sample, the better the generated structure.
Review the Generated Classes
The right panel shows Ruby classes. Use JSON.parse(json) and map the hash to your classes, or use the generated initializers. For Rails, you can add these to app/models or a dedicated DTO folder. Validate JSON first with JSON Validator if needed.
Copy or Download
Use Copy or Download. For formatting JSON first, use the JSON Formatter. For validation, use the JSON Validator.
JSON to Ruby Examples
Here is an example of generating Ruby classes from a JSON object.
Example: Subscriber record
JSON input:
Generated Ruby output:
When JSON to Ruby Helps
When building Rails APIs, Sinatra apps, or Ruby scripts that consume REST APIs, you need typed models for the response payload. Pasting a sample response here gives you Ruby classes you can use with Net::HTTP, Faraday, or HTTParty. Manually writing classes for complex nested JSON is tedious; this tool infers the structure from your sample.
For pulling out specific values from large responses first, use the JSON Path tool. For schema validation, use the JSON Schema Generator. Gems like grape-entity or dry-struct offer additional typing options.
Frequently Asked Questions
Struct vs class?
Structs are lightweight and immutable. Classes give more flexibility for custom behavior. The generator typically produces classes. Use Struct or OpenStruct if you prefer a more dynamic approach.
What about Rails?
Rails uses ActiveModel::Serializers or Jbuilder for API responses. For consuming external APIs, the generated classes work as plain Ruby objects. Add them to lib/ or app/services/ as needed.
Is my data private?
Yes. Generation runs entirely in your browser. No JSON or code is sent to any server.
Symbol keys vs string keys?
JSON.parse returns string keys by default. Use JSON.parse(json, symbolize_names: true) for symbol keys. The generated classes typically expect the structure from JSON.parse.
Can I use with dry-rb?
Yes. dry-struct provides typed structs. You can adapt the generated classes to use Dry::Struct for stricter typing.
Related Tools
For Ruby JSON, see Ruby JSON. For JSON, see json.org and RFC 8259. For MDN JSON. For Postman API testing.