bench.rb

require 'benchmark/ips'
require 'oj'
require 'json'

puts "Ruby version: #{RUBY_VERSION}"
puts "Oj version: #{Oj::VERSION}"
puts "JSON version: #{JSON::VERSION}"

# Sample data to hash - using varied data types
test_data = [1, "string", { a: 1, b: 2 }, [3, 4, 5]]

Benchmark.ips do |x|
  x.config(time: 5, warmup: 2)

  x.report("Oj") do
    Oj.dump(test_data)
  end

  x.report("JSON") do
    JSON.dump(test_data)
  end

  x.compare!
end

result.txt

$ ruby bench.rb
Ruby version: 3.3.4
Oj version: 3.16.6
JSON version: 2.7.4
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin21]
Warming up --------------------------------------
                  Oj   403.745k i/100ms
                JSON   126.032k i/100ms
Calculating -------------------------------------
                  Oj      4.114M (± 1.9%) i/s  (243.07 ns/i) -     20.591M in   5.006862s
                JSON      1.259M (± 3.0%) i/s  (794.42 ns/i) -      6.302M in   5.010755s

Comparison:
                  Oj:  4114033.6 i/s
                JSON:  1258780.8 i/s - 3.27x  slower