How do I remove backslashes from a JSON string?

Replace all backslashes with empty string using gsub:

json.gsub('\\', '')

Note that the default output in a REPL uses inspect, which will double-quote the string and still include backslashes to escape the double-quotes. Use puts to see the string’s exact contents:

{"test":{"test1":{"test1":[{"test2":"1","test3": "foo","test4":"bar","test5":"test7"}]}}}

Further, note that this will remove all backslashes, and makes no regard for their context. You may wish to only remove backslashes preceding a double-quote, in which case you can do:

json.gsub('\"', '')

To avoid generating JSON with backslashes in console, use puts:

> hash = {test: 'test'}
=> {:test=>"test"}

> hash.to_json
 => "{\"test\":\"test\"}"

> puts hash.to_json
{"test":"test"}

You could also use JSON.pretty_generate, with puts of course.

> puts JSON.pretty_generate(hash)
{
  "test": "test"
}

Use Ruby's String#delete! method. For example:

str = '{\"test\":{\"test1\":{\"test1\":[{\"test2\":\"1\",\"test3\": \"foo\",\"test4\":\"bar\",\"test5\":\"test7\"}]}}}'
str.delete! '\\'
puts str
#=> {"test":{"test1":{"test1":[{"test2":"1","test3": "foo","test4":"bar","test5":"test7"}]}}}