JSON Formatter, Minifier, and Validator in Ruby — Code Examples

JSON parsing and serialisation is built into every major language. Here is how to parse a JSON string, format (pretty-print) JSON, and handle common edge cases in each language.

Ruby's standard library includes the json gem. Use JSON.parse to decode and JSON.generate (or JSON.pretty_generate) to encode.

require 'json'

# Parse JSON string → hash
data = JSON.parse('{"name":"Alice","age":30}')
puts data["name"] # Alice

# Parse with symbol keys
data_sym = JSON.parse('{"name":"Alice","age":30}', symbolize_names: true)
puts data_sym[:name] # Alice

# Serialize hash → JSON
json_str = JSON.generate(data)
puts json_str # {"name":"Alice","age":30}

# Pretty-print
pretty = JSON.pretty_generate(data)
puts pretty

# Error handling
begin
  JSON.parse("invalid json")
rescue JSON::ParserError => e
  puts "Parse error: #{e.message}"
end

# Arrays and nested objects work the same way
puts [1, "hello", nil, true].to_json # [1,"hello",null,true]

• symbolize_names: true converts all string keys to symbols — convenient but use with caution on untrusted input (Symbol objects are not GC'd in older Ruby versions).
• JSON.generate and .to_json produce the same output; .to_json is added to all objects by the json gem.
• Rescue JSON::ParserError (not StandardError) for precise error handling on malformed input.

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