diff --git a/.gitignore b/.gitignore
index b04a8c8..5256187 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,5 +7,7 @@
 /spec/reports/
 /tmp/
 
+.env
+
 # rspec failure tracking
-.rspec_status
+.rspec_status
\ No newline at end of file
diff --git a/Gemfile b/Gemfile
index d2fceab..cd3507a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,3 +3,5 @@ source "https://rubygems.org"
 git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
 
 gemspec
+
+gem 'dotenv'
diff --git a/Gemfile.lock b/Gemfile.lock
index d8e06f7..e374b0e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,12 +2,26 @@ PATH
   remote: .
   specs:
     mapon_client (0.1.0)
+      rest-client (> 1)
 
 GEM
   remote: https://rubygems.org/
   specs:
     diff-lcs (1.3)
+    domain_name (0.5.20170404)
+      unf (>= 0.0.5, < 1.0.0)
+    dotenv (2.2.1)
+    http-cookie (1.0.3)
+      domain_name (~> 0.5)
+    mime-types (3.1)
+      mime-types-data (~> 3.2015)
+    mime-types-data (3.2016.0521)
+    netrc (0.11.0)
     rake (10.5.0)
+    rest-client (2.0.2)
+      http-cookie (>= 1.0.2, < 2.0)
+      mime-types (>= 1.16, < 4.0)
+      netrc (~> 0.8)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
       rspec-expectations (~> 3.7.0)
@@ -21,12 +35,16 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.7.0)
     rspec-support (3.7.1)
+    unf (0.1.4)
+      unf_ext
+    unf_ext (0.0.7.5)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   bundler (~> 1.16)
+  dotenv
   mapon_client!
   rake (~> 10.0)
   rspec (~> 3.0)
diff --git a/README.md b/README.md
index 710365c..e0d378b 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,25 @@ Or install it yourself as:
 
 ## Usage
 
-TODO: Write usage instructions here
+### Instantiate client:
+  * api_key - create it under Settings/API keys, if blank, will try to read environment variable MAPON_CLIENT_API_KEY on the [site](https://mapon.com/new/settings#9) 
+  * base_url - defaults to https://mapon.com/api/v1/
+  * format - json/xml, defaults to json
+
+```ruby
+mapon_client = MaponClient::Client.new
+# OR
+mapon_client = MaponClient::Client.new(
+  api_key: ENV['BY_DIFFERENT_NAME_API_KEY'],
+  base_url: 'https://mapon.com/api/v300/not-the-default-endpoint',
+  format: 'xml'
+)
+```
+### Rest client
+
+MaponClient uses [rest-client](https://github.com/rest-client/rest-client) as HTTP client.
+So on any lower level calls rest-client library class instances gets returned,
+like RestClient::Response, RestClient::Resource, etc.
 
 ## Development
 
diff --git a/bin/console b/bin/console
index a77a7ba..b5a269a 100755
--- a/bin/console
+++ b/bin/console
@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 
 require "bundler/setup"
+require "dotenv/load"
 require "mapon_client"
 
 # You can add fixtures and/or initialization code here to make experimenting
diff --git a/lib/mapon_client.rb b/lib/mapon_client.rb
index 60ffdfc..f6e3fc3 100644
--- a/lib/mapon_client.rb
+++ b/lib/mapon_client.rb
@@ -1,4 +1,8 @@
 require "mapon_client/version"
 
 module MaponClient
+  DEFAULT_BASE_URL = 'https://mapon.com/api/v1/'.freeze
+  DEFAULT_FORMAT = 'json'.freeze
+
+  autoload :Client, 'mapon_client/client'
 end
diff --git a/lib/mapon_client/client.rb b/lib/mapon_client/client.rb
new file mode 100644
index 0000000..e91fc69
--- /dev/null
+++ b/lib/mapon_client/client.rb
@@ -0,0 +1,43 @@
+require 'rest-client'
+
+module MaponClient
+  class Client
+    attr_reader :api_key, :base_url, :resource_base, :format
+
+    def initialize(api_key: nil, base_url: nil, format: nil)
+      @api_key = (
+        api_key || ENV['MAPON_CLIENT_API_KEY']
+      )
+
+      @base_url = (
+        base_url || MaponClient::DEFAULT_BASE_URL
+      )
+
+      @format = (
+        format || MaponClient::DEFAULT_FORMAT
+      )
+
+      @resource_base ||= RestClient::Resource.new(
+        @base_url, headers: { params: { key: @api_key } }
+      )
+    end
+
+    def [](*args)
+      @resource_base.public_send(:[], *args)
+    end
+
+    def company
+      self[with_format("company/get")].get
+    end
+
+    def unit_list
+      self[with_format("unit/list")].get
+    end
+
+    private
+
+    def with_format(suburl)
+      "#{suburl}.#{@format}"
+    end
+  end
+end
diff --git a/mapon_client.gemspec b/mapon_client.gemspec
index 3d388f1..a12ae2c 100644
--- a/mapon_client.gemspec
+++ b/mapon_client.gemspec
@@ -29,6 +29,8 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
+  spec.add_dependency "rest-client", ">1"
+
   spec.add_development_dependency "bundler", "~> 1.16"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
diff --git a/spec/mapon_client/client_spec.rb b/spec/mapon_client/client_spec.rb
new file mode 100644
index 0000000..941ccbb
--- /dev/null
+++ b/spec/mapon_client/client_spec.rb
@@ -0,0 +1,16 @@
+RSpec.describe MaponClient::Client do
+
+  let(:mapon_client) {
+    MaponClient::Client.new(
+      api_key: 'fake_key_123',
+      base_url: 'https://mapon.com/api/v1',
+      format: 'json'
+    )
+  }
+
+  it "#[] should delegate calls to #resource_base" do
+    block_to_pass = Proc.new { }
+    expect(mapon_client.resource_base).to receive(:[]).with('company/get', &block_to_pass)
+    mapon_client.public_send(:[], 'company/get', &block_to_pass)
+  end
+end
diff --git a/spec/mapon_client_spec.rb b/spec/mapon_client_spec.rb
index 6051aff..238f87a 100644
--- a/spec/mapon_client_spec.rb
+++ b/spec/mapon_client_spec.rb
@@ -2,4 +2,8 @@
   it "has a version number" do
     expect(MaponClient::VERSION).not_to be nil
   end
+
+  it "::DEFAULT_BASE_URL should be https://api.mapon.com/api/v1/" do
+    expect(MaponClient::DEFAULT_BASE_URL).to eq("https://mapon.com/api/v1/")
+  end
 end