Create your own API so other tools like Postman or other computers in your network can get what they need for the tests or for whatever you need. Run in command line ruby api.rb to fire up this API. Access from any computer inside your network, for example to get 30 random emails, write in your browser: mycomputer:4567/gen?pattern=20-50:@&num=30

api.rb

# libraries we will use in our api
# documentation: https://github.com/MarioRuiz/string_pattern
# documentation: https://github.com/MarioRuiz/nice_hash
require "sinatra"
require "string_pattern"
require "nice_hash"

set :protection, :except => :frame_options
set :bind, "0.0.0.0"

get "/" do
  "Hello from #{request.host}"
end

# examples: 
#   mycomputername:4567/gen/10-20:LN
#   mycomputername:4567/gen/30:@
get "/gen/*" do
  params[:splat].gen
end

# examples:
#   mycomputername:4567/gen?pattern=20:LN
#   mycomputername:4567/gen?pattern=20:@&num=20
get "/gen" do
  if params.key?(:pattern)
    if params[:num].to_i > 10000
      num = 10000
    elsif params[:num].to_i == 0
      num = 1
    else
      num = params[:num].to_i
    end
    resp = Array.new
    num.times do
      resp << params[:pattern].gen
    end
    resp.join("\n")
  end
end

# examples to generate a random JSON data following the patterns specified:
#   send a POST to mycomputername:4567/gen with the JSON data:
#     {
#        "loginame": "5-10:/xn/", 
#        "password": "5-10:L/n/",
#        "name": "10-20:T_/x/",
#        "zip": '5:N',
#        "address": "21 Doom Av",
#        "city": "London|Rome",
#        "mobilePhone": ['(', '3:N', ')', '6-8:N'],
#        "sex": "male|female|other",
#        "customer": "true"
#     }
post "/gen" do
  data = request.body.read
  if data.json.key?(:pattern) and data.json.size == 1
    if data.json(:pattern)[0] == "(" and data.json(:pattern)[-1] == ")" #regular expression
      res = (Regexp.new data.json(:pattern)).gen
    else
      res = data.json(:pattern).gen
    end
  else
    res = data.json.gen.to_json
  end
  res
end