diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..097a15a
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.6.2
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..e3ca081
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,6 @@
+source "https://rubygems.org"
+
+git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
+
+# Specify your gem's dependencies in girocode.gemspec
+gemspec
diff --git a/LICENSE b/LICENSE
index 44a353d..aaa5544 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-MIT License
+The MIT License (MIT)
 
 Copyright (c) 2019 Matthias Grosser
 
@@ -18,4 +18,4 @@ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
+SOFTWARE.
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..72e4ec5
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+# Girocode
+
+Create QR codes for SEPA bank transfers.
+
+## Installation
+
+Add this line to your application's Gemfile:
+
+```ruby
+gem 'girocode'
+```
+
+## Usage
+
+```ruby
+code = Girocode.new(iban: 'DE02100500000054540402', name: 'Beispiel AG', currency: 'EUR', amount: 123.45, reference: 'RE 2019/05/445 744507')
+
+code.to_svg
+code.to_png
+code.to_html
+
+# in your console
+puts code.to_ansi
+```
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..d433a1e
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,10 @@
+require "bundler/gem_tasks"
+require "rake/testtask"
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << "test"
+  t.libs << "lib"
+  t.test_files = FileList["test/**/*_test.rb"]
+end
+
+task :default => :test
diff --git a/bin/console b/bin/console
new file mode 100755
index 0000000..c93ab13
--- /dev/null
+++ b/bin/console
@@ -0,0 +1,14 @@
+#!/usr/bin/env ruby
+
+require "bundler/setup"
+require "girocode"
+
+# You can add fixtures and/or initialization code here to make experimenting
+# with your gem easier. You can also use a different console, if you like.
+
+# (If you use this, don't forget to add pry to your Gemfile!)
+# require "pry"
+# Pry.start
+
+require "irb"
+IRB.start(__FILE__)
diff --git a/bin/setup b/bin/setup
new file mode 100755
index 0000000..dce67d8
--- /dev/null
+++ b/bin/setup
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+set -vx
+
+bundle install
+
+# Do any other automated setup that you need to do here
diff --git a/girocode.gemspec b/girocode.gemspec
new file mode 100644
index 0000000..1a3ec90
--- /dev/null
+++ b/girocode.gemspec
@@ -0,0 +1,25 @@
+lib = File.expand_path('../lib', __FILE__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'girocode/version'
+
+Gem::Specification.new do |s|
+  s.name          = 'girocode'
+  s.version       = Girocode::VERSION
+  s.authors       = ['Matthias Grosser']
+  s.email         = ['mtgrosser@gmx.net']
+
+  s.summary       = %q{Generate QR codes for SEPA credit transfers}
+  s.description   = %q{EPC QR code for SEPA payments in any format}
+  s.homepage      = 'https://github.com/mtgrosser/girocode'
+
+  s.files         = Dir['{lib}/**/*.rb', 'LICENSE', 'README.md', 'CHANGELOG', 'Rakefile']
+  s.require_paths = ['lib']
+
+  s.add_dependency 'rqrcode'
+  s.add_dependency 'bank-contact'
+
+  s.add_development_dependency 'bundler', '~> 1.17'
+  s.add_development_dependency 'rake', '~> 10.0'
+  s.add_development_dependency 'minitest', '~> 5.0'
+  s.add_development_dependency 'simplecov'
+end
diff --git a/lib/girocode.rb b/lib/girocode.rb
new file mode 100644
index 0000000..cf1775a
--- /dev/null
+++ b/lib/girocode.rb
@@ -0,0 +1,12 @@
+require 'bigdecimal'
+require 'bank/contact'
+require 'rqrcode'
+
+require_relative 'girocode/version'
+require_relative 'girocode/code'
+
+module Girocode
+  def self.new(**attrs)
+    Girocode::Code.new(**attrs)
+  end
+end
diff --git a/lib/girocode/code.rb b/lib/girocode/code.rb
new file mode 100644
index 0000000..9b41b2d
--- /dev/null
+++ b/lib/girocode/code.rb
@@ -0,0 +1,119 @@
+module Girocode
+  class Error < StandardError; end
+  
+  class Code
+    ATTRIBUTES = %i[bic name iban currency amount purpose creditor_reference reference bto_info]
+    attr_reader *ATTRIBUTES
+    
+    MAX_PAYLOAD_BYTES = 331
+    AMOUNT_RANGE = BigDecimal('0.01')..BigDecimal('999999999.99')
+    
+    def initialize(**attrs)
+      if keys = attrs.keys - ATTRIBUTES and not keys.empty?
+        raise ArgumentError, "Illegal attributes #{keys.inspect}"
+      end
+      attrs.each { |attr, value| send("#{attr}=", value) }
+      raise ArgumentError, "iban is required" unless iban?
+      raise ArgumentError, "name is required" unless name?
+      raise ArgumentError, 'currency is required for amount' if amount && !currency?
+      raise ArgumentError, "either creditor reference or reference may be set" if creditor_reference? && reference?
+      raise ArgumentError, "payload too long" if payload.bytesize > MAX_PAYLOAD_BYTES
+    end
+    
+    def bic=(value)
+      if value.nil?
+        @bic = nil
+      else
+        bic = Bank::BIC.new(value)
+        raise ArgumentError, "Invalid BIC #{value.inspect}" unless bic.valid?
+        @bic = bic.to_s
+      end
+    end
+    
+    def name=(value)
+      value = value.strip
+      raise ArgumentError, 'name is required' unless value
+      raise ArgumentError, 'name too long' if value.size > 70
+      raise ArgumentError, 'Illegal name' if value.include?("\n") || value.include?("\r")
+      @name = value
+    end
+    
+    def iban=(value)
+      iban = Bank::IBAN.new(value)
+      raise ArgumentError, "Invalid IBAN #{value.inspect}" unless iban.valid?
+      @iban = iban.to_s
+    end
+    
+    def currency=(value)
+      value = value.to_s.upcase
+      raise ArgumentError, "Invalid currency" unless value.match?(/\A[A-Z]{3}\z/)
+      @currency = value
+    end
+    
+    def amount=(value)
+      raise ArgumentError, 'amount is required' unless value
+      value = BigDecimal(value, Float::DIG + 1)
+      raise ArgumentError, "invalid amount #{value.inspect}" unless AMOUNT_RANGE.cover?(value)
+      @amount = value
+    end
+    
+    def purpose=(value)
+      unless value.nil?
+        raise ArgumentError, "invalid purpose #{value.inspect}" unless value.match?(/\A[A-z0-9]{0,4}\z/)
+      end
+      @purpose = value
+    end
+    
+    def creditor_reference=(value)
+      unless value.nil?
+        raise ArgumentError, "invalid creditor reference #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 35
+      end
+      @creditor_reference = value
+    end
+    
+    def reference=(value)
+      unless value.nil?
+        raise ArgumentError, "invalid reference #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 140
+      end
+      @reference = value
+    end
+    
+    def bto_info=(value)
+      unless value.nil?
+        raise ArgumentError, "invalid bto_info #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 70
+      end
+      @bto_info = value
+    end
+    
+    ATTRIBUTES.each do |attr|
+      define_method("#{attr}?") do
+        value = instance_variable_get("@#{attr}")
+        value.respond_to?(:empty?) ? !value.empty? : !!value
+      end
+    end
+    
+    def payload
+      ['BCD', '002', '1', 'SCT',
+       bic, name, iban,formatted_amount, purpose,
+       creditor_reference || reference, bto_info].map(&:to_s).join("\n")
+    end
+    
+    def to_qrcode
+      RQRCode::QRCode.new(payload, level: :m, mode: :byte_8bit)
+    end
+    
+    def to_ascii
+      to_qrcode.to_s
+    end
+    
+    %i[png svg html ansi].each do |format|
+      define_method("to_#{format}") { |*args| to_qrcode.public_send("as_#{format}", *args) }
+    end
+    
+    private
+    
+    def formatted_amount
+      "#{currency}#{amount.round(2).to_s('F')}" if currency? && amount
+    end
+  end
+end
diff --git a/lib/girocode/version.rb b/lib/girocode/version.rb
new file mode 100644
index 0000000..2c65062
--- /dev/null
+++ b/lib/girocode/version.rb
@@ -0,0 +1,3 @@
+module Girocode
+  VERSION = "0.1.0"
+end
diff --git a/test/data.txt b/test/data.txt
new file mode 100644
index 0000000..2a3e248
--- /dev/null
+++ b/test/data.txt
@@ -0,0 +1,41 @@
+xxxxxxx xxx   xx  xx xx xxxx x  x xxxxxxx
+x     x xxxxx  xxx xx   xxx   xx  x     x
+x xxx x x   x    xxxxx xxx  x xxx x xxx x
+x xxx x   xx  xxx     x xxxxxxx   x xxx x
+x xxx x xx x xx x xxxxxx x   x x  x xxx x
+x     x  xxx  xx xx x  xxx x xx x x     x
+xxxxxxx x x x x x x x x x x x x x xxxxxxx
+         xx       xxx    xxx    x        
+x  xxxxxx    x x   xxx  xxxxx xxxx  x xxx
+ xx  x xx  xx xx      x   x x xxxx  x x x
+xx  xxx x  xx  xxxx xxxxx  x x  x   x    
+ x x    xxxx   xxxx    x     xxx xxxxx   
+xx  xxx  xx  xx   x   x x  x     xxx xxxx
+x x x  xx  x xxxx  xxxx  xxx  x xxx xxxxx
+x  xxxxxx xx   x   xx  xxxxx x x xx  xxxx
+ xx  x xx  xx xx  x x xx   x  x x x  xx x
+xxxxxxx xxx   xx x  x      x  x  x     x 
+ xx    x  xxxx x x  xx  x x xx x x xx  x 
+  xxx x   x x    xxx   x  xx   xxxxx    x
+xxx xx x  x x        x  xx     x     xx x
+ x x  x xx  xxx x xxxx  x   xxxxx xx  x x
+xxx xx  xx x     x xx x      x x  x xxx x
+ x    x   x xxxx xx  xxxxxx x x  x xx    
+ x xxx  x xx  x  xx     x    xx x  x   xx
+x xxx x xx  x   xxxx x  xx   x xxxx    xx
+x    x x  x xx    xx      x x  xxxx xxxx 
+x x xxxxxx   xxxxxxx    x xx   x xx x x x
+xxx  x xxxx xx xx x x  xx xxx  xxx  xxx  
+xx x xx  xx    x  xxx  xxx xx    x    xxx
+xx   x  xx   x xxx  x  xx  xxx x x  x  x 
+xx x xxxxx   x  x x x xxxx xx  x xxx  xxx
+xx xxx  xxx    xx     xxxx  x  xx  x  x x
+xxx   xxxx    x   x  xxx xxx xx xxxxxxxxx
+        xx xxx xxxx   xxx  xx  xx   x x x
+xxxxxxx x   x  x    xx xx  x x xx x xx   
+x     x x xxxx    xx    x   xx  x   x    
+x xxx x xx x xx  x   xxxxxx x xxxxxxx  x 
+x xxx x xx x    xxx xxx x xxx       xxx x
+x xxx x    x  xxxxxxxxx xx xxxxx    x   x
+x     x     x x x x x xx  xxx  x x  x x x
+xxxxxxx x   x xx x  xxx x  x x xx   xx   
\ No newline at end of file
diff --git a/test/girocode_test.rb b/test/girocode_test.rb
new file mode 100644
index 0000000..5d2eda3
--- /dev/null
+++ b/test/girocode_test.rb
@@ -0,0 +1,19 @@
+require_relative 'test_helper'
+
+class GirocodeTest < Minitest::Test
+  def test_that_it_has_a_version_number
+    refute_nil ::Girocode::VERSION
+  end
+
+  def test_girocode
+    attrs = { bic: 'BHBLDEHHXXX', name: 'Franz Mustermänn', iban: 'DE71110220330123456789', currency: :eur, amount: 12.3, purpose: 'GDDS', creditor_reference: 'RF18539007547034' }
+    code = Girocode.new(attrs)
+    assert_equal data(:data), code.to_ascii
+  end
+  
+  private
+  
+  def data(name)
+    Pathname(__dir__).join("#{name}.txt").read
+  end
+end
diff --git a/test/test_helper.rb b/test/test_helper.rb
new file mode 100644
index 0000000..161cd29
--- /dev/null
+++ b/test/test_helper.rb
@@ -0,0 +1,30 @@
+ENV["RAILS_ENV"] = "test"
+
+require 'pathname'
+
+if RUBY_VERSION >= '1.9'
+  require 'simplecov'
+  SimpleCov.start do
+    if artifacts_dir = ENV['CC_BUILD_ARTIFACTS']
+      coverage_dir Pathname.new(artifacts_dir).relative_path_from(Pathname.new(SimpleCov.root)).to_s
+    end
+    add_filter '/test/'
+    add_filter 'vendor'
+  end
+
+  SimpleCov.at_exit do
+    SimpleCov.result.format!
+    if result = SimpleCov.result
+      File.open(File.join(SimpleCov.coverage_path, 'coverage_percent.txt'), 'w') { |f| f << result.covered_percent.to_s }
+    end
+  end
+end
+
+require 'rubygems'
+require 'bundler/setup'
+Bundler.require(:default)
+#require 'byebug'
+
+require 'minitest/autorun'
+
+require 'girocode'