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JSON to Ruby

Generate Ruby classes/structs automatically from a JSON object.

100% Client-Side Local Execution
Class Name:
Input Data
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Transformed Result
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What is JSON to Ruby?

This free online tool turns a sample JSON payload into a ready-to-use class (or Struct) with attr_accessor for Ruby, so you can use this json to ruby class generator tool to go straight from raw JSON to a typed class or Struct without writing the boilerplate yourself. It is built around Ruby's actual idiom — a Ruby class — rather than a generic one-size-fits-all class, and pairs naturally with Ruby's built-in JSON module for real-world (de)serialization. Use it for json to ruby hash class or any time you need ruby class from json online, whether you're scaffolding a new Ruby project or mapping an existing API response.

Technical Execution

Paste or upload a sample JSON object or array and the tool walks its structure field by field, inferring a concrete Ruby type for each value — mapping basic JSON types to `String`, `Integer`/`Float`, and `true`/`false` as appropriate. For nested data, it generates a separate class (or `Struct.new`) for every nested JSON object, each exposed via `attr_accessor`, and represents arrays as plain Ruby `Array` of the matching nested class. On the naming side, it keeps snake_case keys as-is since that matches Ruby's idiomatic naming convention, and only renames a key when it isn't a valid Ruby identifier. For optional data, fields observed as `null`, or missing from some sample objects, are simply left unset (Ruby's dynamic typing means `nil` is always a valid value), and the generated initializer uses keyword arguments with `nil` defaults for them.

Zero Data Storage Guarantee

Everything runs client-side in your browser: the sample JSON you paste in — which may contain real field names, endpoint shapes, or structure from a private API or project — is parsed and converted entirely on your device and is never uploaded to any server. Nothing you enter is logged, stored, or transmitted anywhere, so you can safely paste a real payload from an internal or unreleased API to generate an accurate Ruby class. Closing or refreshing the tab clears everything, since no copy of your data ever left your machine in the first place.

How to Use JSON to Ruby (Step-by-Step Guide)

  1. Copy a representative sample of your JSON (the more fields and nested objects it includes, the more complete the generated class or Struct will be).
  2. Paste it into the input panel of the JSON to Ruby tool, or click "Upload" to load it from a json file.
  3. Review the auto-detected root name, and rename it if you want the generated Ruby class to use a specific class or type name instead of the default.
  4. Click "Generate" to produce the Ruby class or Struct, which appears instantly in the output panel with syntax highlighting.
  5. Click "Copy" to copy the generated code to your clipboard, or "Download" to save it as a `.rb` file.
  6. Paste the result into your Ruby project and adjust field names or types if your data has edge cases the sample didn't cover.

Frequently Asked Questions (FAQ)

Q: How does this tool handle nested objects and arrays when converting JSON to Ruby?
A: The tool generates a separate class (or `Struct.new`) for every nested JSON object, each exposed via `attr_accessor`, and represents arrays as plain Ruby `Array` of the matching nested class That keeps the generated code organized the way a Ruby developer would structure it by hand, instead of flattening everything into one giant class or Struct.
Q: What happens to fields that are nullable or missing from some records?
A: For optional data, fields observed as `null`, or missing from some sample objects, are simply left unset (Ruby's dynamic typing means `nil` is always a valid value), and the generated initializer uses keyword arguments with `nil` defaults for them. If your sample only has one example object, fields that could be null in other records might not be detected as optional — paste a few varied samples (or an array of objects) for the most accurate result.
Q: Is this better than writing the class or Struct by hand?
A: For anything beyond a trivial, flat payload, yes — writing a Ruby class with `attr_accessor` for every field of a nested API response by hand is quick for small payloads but easy to get inconsistent across a larger, deeply nested one. The generator produces the same result in seconds and gives you a correct starting point to refine, rather than a blank page.
Q: Is my JSON data safe to paste into this tool, especially if it's from a private API?
A: Yes. Everything runs client-side in your browser: the sample JSON you paste in — which may contain real field names, endpoint shapes, or structure from a private API or project — is parsed and converted entirely on your device and is never uploaded to any server. Nothing you enter is logged, stored, or transmitted anywhere, so you can safely paste a real payload from an internal or unreleased API to generate an accurate Ruby class. Closing or refreshing the tab clears everything, since no copy of your data ever left your machine in the first place.
Q: Can I use this as a convert json to ruby object?
A: Yes — the tool is commonly used as a convert json to ruby object, and works the same way whether you're converting a one-off response for a prototype or generating model code for a production project.
Q: Does the tool rename fields to match Ruby naming conventions?
A: Yes. It keeps snake_case keys as-is since that matches Ruby's idiomatic naming convention, and only renames a key when it isn't a valid Ruby identifier, so the generated code reads naturally in Ruby while still deserializing the original JSON correctly.
Q: What Ruby library does the generated code work with?
A: The output is written to pair cleanly with Ruby's built-in JSON module, the most common choice for Ruby developers handling JSON, so you can drop it into an existing project without changing your serialization setup.
Q: Does this tool work for deeply nested or large JSON samples?
A: Yes. The tool recurses through every level of nesting it finds and generates a complete set of linked class or Struct definitions, not just the top level — though for very large samples, trimming it down to one representative record per array is usually enough to get an accurate result.
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