Ruby to JSON Converter — Convert Ruby Hashes to JSON Online
Convert Ruby hashes, arrays, symbols, booleans, and nil values to JSON using AI. Generates valid JSON with double quotes and proper null, true, and false values. Free, no sign-up.
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Ruby to JSON Converter — Convert Ruby Hashes to JSON Online
About Ruby to JSON Converter — Convert Ruby Hashes to JSON Online
This tool converts Ruby Hash and Array literal syntax into valid JSON, handling symbol keys, nil values, and Ruby-specific data types that are incompatible with the JSON specification. Developers use it to quickly transform Ruby object representations — commonly copied from Rails console output, IRB sessions, or test fixtures — into JSON without writing a script or booting a Rails environment.
Ruby to JSON Type Mapping
| Ruby Type | Ruby Example | JSON Output | Notes |
|---|---|---|---|
| Symbol key | :name => "Alice" | "name": "Alice" | Symbols converted to quoted strings |
| String key | "name" => "Alice" | "name": "Alice" | Unchanged |
| Integer | age: 30 | "age": 30 | Unchanged |
| Float | score: 9.5 | "score": 9.5 | Unchanged |
| Boolean true | active: true | "active": true | Unchanged |
| Boolean false | active: false | "active": false | Unchanged |
| Nil | value: nil | "value": null | nil maps to JSON null |
| Array | tags: [1, 2] | "tags": [1, 2] | Unchanged |
| Nested Hash | user: {id: 1} | "user": {"id": 1} | Recursively converted |
| Symbol value | status: :ok | "status": "ok" | Symbol values become strings |
Ruby Data Serialization Options Compared
| Format | Human Readable | Schema Enforced | Native Ruby Support | Interoperable | Common Use Case |
|---|---|---|---|---|---|
| JSON | Yes | No (optional) | Yes (stdlib) | Universal | APIs, config, data exchange |
| YAML | Yes | No | Yes (Psych) | Partial | Rails config, test fixtures |
| MessagePack | No | No | Gem required | Wide | High-performance serialization |
| Marshal | No | No | Yes (stdlib) | Ruby only | Ruby process caching |
| XML | Yes | Yes (XSD) | Yes (REXML) | Universal | Legacy enterprise APIs |
| BSON | No | No | Gem required | MongoDB ecosystem | MongoDB documents |
Frequently Asked Questions
How do I convert a Ruby hash to JSON in Rails?
In Rails, call `.to_json` on any Hash or ActiveRecord object — it's available via the `json` gem included by default. For a plain hash like `{name: 'Alice', age: 30}`, calling `.to_json` produces `{"name":"Alice","age":30}`. Symbol keys are automatically stringified. Use `JSON.pretty_generate(hash)` from the stdlib if you need human-readable indented output.
Why does Ruby hash use symbols but JSON requires strings?
Ruby symbols (`:name`) are an immutable, memory-efficient identifier type specific to Ruby's runtime — they have no equivalent in the JSON specification, which only allows string keys. When serializing to JSON, symbol keys must be converted to their string representation. The `json` gem does this automatically; if you use `.to_json` or `JSON.generate`, all symbol keys are quoted as strings in the output.
How to convert Ruby nil to JSON null?
Ruby's `nil` maps directly to JSON's `null` — the `json` gem handles this automatically when you call `.to_json` or `JSON.generate`. For example, `{value: nil}.to_json` produces `{"value":null}`. If you are pasting raw Ruby syntax into a converter tool, `nil` will likewise be replaced with `null` in the JSON output.
What is the difference between JSON.generate and .to_json in Ruby?
`JSON.generate(obj)` is a module method from the stdlib `json` gem that serializes an object to a compact JSON string. `.to_json` is an instance method added to core Ruby classes (Hash, Array, String, etc.) by the same gem and behaves identically for standard types. The practical difference is that `JSON.generate` accepts an options hash as a second argument for controlling output (e.g., indentation), while `JSON.pretty_generate` is the recommended method when you want formatted output.
Can I convert Ruby array of hashes to a JSON array?
Yes — a Ruby Array containing Hash objects serializes directly to a JSON array of objects. For example, `[{id: 1, name: 'Alice'}, {id: 2, name: 'Bob'}].to_json` produces `[{"id":1,"name":"Alice"},{"id":2,"name":"Bob"}]`. Nested structures are handled recursively, and symbol keys at every level are converted to strings. Paste the Ruby literal into this tool and it will output the equivalent valid JSON array.
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