diff --git a/lib/channel.rb b/lib/channel.rb
new file mode 100644
index 00000000..748cc155
--- /dev/null
+++ b/lib/channel.rb
@@ -0,0 +1,48 @@
+require "httparty"
+require "dotenv"
+require_relative "recipient"
+
+Dotenv.load
+
+module SlackCLI
+  class Channel < Recipient
+    BASE_URL = "https://slack.com/api/channels.list"
+
+    attr_reader :topic, :members
+
+    def initialize(slack_id, name, topic, members)
+      super(slack_id, name)
+      @topic = topic
+      @members = members
+    end
+
+    def self.get_from_api
+      query_parameters = {
+        token: ENV["OAUTH_ACCESS_TOKEN"],
+      }
+
+      response = get(BASE_URL, query_parameters)
+
+      if (response.code == 200)
+        channels = response["channels"].map do |channel|
+          slack_id = channel["id"]
+          channel_name = channel["name"]
+          topic = channel["topic"]["value"]
+          members = channel["members"].length
+          new(slack_id, channel_name, topic, members)
+        end
+        return channels
+      else
+        raise SlackApiError, "Error #{response.code} : #{response["message"]}"
+      end
+    end
+
+    def display_details
+      info_string = "\nSlack ID : #{slack_id}" +
+                    "\nChannel name : #{name}" +
+                    "\nTopic : #{topic}" +
+                    "\nMember count: #{members}"
+      return info_string
+    end
+  end
+end
diff --git a/lib/recipient.rb b/lib/recipient.rb
new file mode 100644
index 00000000..4d3fb923
--- /dev/null
+++ b/lib/recipient.rb
@@ -0,0 +1,38 @@
+module SlackCLI
+  class Recipient
+    CHAT_ENDPOINT = "https://slack.com/api/chat.postMessage"
+    attr_reader :slack_id, :name
+
+    def initialize(slack_id, name)
+      @name = name
+      @slack_id = slack_id
+    end
+
+    def self.get(url, params)
+      return HTTParty.get(url, query: params)
+    end
+
+    def send_message(message)
+      query_parameters = {
+        token: ENV["OAUTH_ACCESS_TOKEN"],
+        channel: slack_id,
+        text: message,
+      }
+      response = HTTParty.post(
+        CHAT_ENDPOINT,
+        body: query_parameters,
+        headers: { "Content-Type" => "application/x-www-form-urlencoded" },
+      )
+
+      return response.code == 200 && response.parsed_response["ok"]
+    end
+
+    def display_details
+      raise NotImplementedError, "Implement me in a child class!"
+    end
+
+    def self.get_from_api
+      raise NotImplementedError, "Implement me in a child class!"
+    end
+  end
+end
diff --git a/lib/slack.rb b/lib/slack.rb
index 960cf2f7..b4ef2de2 100755
--- a/lib/slack.rb
+++ b/lib/slack.rb
@@ -1,11 +1,85 @@
 #!/usr/bin/env ruby
+require_relative "channel"
+require_relative "user"
+require_relative "workspace"
+
+require "httparty"
+require "dotenv"
+require "awesome_print"
+require "colorize"
+
+Dotenv.load
+
+def set_main_menu_input
+  puts "What would you like to do?".colorize(:yellow)
+  puts "\nOptions: \n1.list users \n2.list channels \n3.select user \n4.select channel \n5.quit".colorize(:blue)
+  input = gets.chomp.downcase
+  return input
+end
+
+def set_selected_input
+  puts "\nOptions: \ndetails \nsend message \nreturn to main menu".colorize(:blue)
+  input = gets.chomp.downcase
+  return input
+end
+
+def selected_loop(input, workspace)
+  until (input == "return to main menu")
+    case input
+    when "details"
+      puts workspace.show_details.colorize(:green)
+    when "send message"
+      puts "Type a message to send:".colorize(:blue)
+      message = gets.chomp
+      workspace.send_message(message)
+    when "return to main menu"
+      break
+    else
+      puts "That wasn't one of the options!".colorize(:red)
+    end
+    input = set_selected_input
+  end
+end
 
 def main
-  puts "Welcome to the Ada Slack CLI!"
+  users = SlackCLI::User.get_from_api
+  channels = SlackCLI::Channel.get_from_api
+  workspace = SlackCLI::Workspace.new(users: users, channels: channels)
+
+  puts "Welcome to the Ada Slack CLI!".colorize(:yellow)
+  input = set_main_menu_input
+
+  until (input == "quit")
+    case input
+    when "list users"
+      workspace.display_users
+    when "list channels"
+      workspace.display_channels
+    when "select user"
+      puts "Enter username or slack id:".colorize(:yellow)
+
+      name_or_id = gets.chomp
+      workspace.select_user(name_or_id)
+
+      input = set_selected_input
+      selected_loop(input, workspace)
+    when "select channel"
+      puts "Enter channel name or id:".colorize(:blue)
+      name_or_id = gets.chomp
+      workspace.select_channel(name_or_id)
+
+      input = set_selected_input
 
-  # TODO project
+      selected_loop(input, workspace)
+    when "quit"
+      break
+    else
+      puts "That wasn't one of the options!".colorize(:red)
+    end
+    input = set_main_menu_input
+  end
 
-  puts "Thank you for using the Ada Slack CLI"
+  puts "Thank you for using the Ada Slack CLI.".colorize(:yellow)
 end
 
-main if __FILE__ == $PROGRAM_NAME
\ No newline at end of file
+main if __FILE__ == $PROGRAM_NAME
diff --git a/lib/user.rb b/lib/user.rb
new file mode 100644
index 00000000..c8907a24
--- /dev/null
+++ b/lib/user.rb
@@ -0,0 +1,46 @@
+require "httparty"
+require "dotenv"
+require "pry"
+require "table_print"
+require_relative "recipient"
+
+Dotenv.load
+
+module SlackCLI
+  class User < Recipient
+    BASE_URL = "https://slack.com/api/users.list"
+    attr_reader :real_name
+
+    def initialize(name, real_name, slack_id)
+      super(slack_id, name)
+      @real_name = real_name
+    end
+
+    def self.get_from_api
+      query_parameters = {
+        token: ENV["OAUTH_ACCESS_TOKEN"],
+      }
+
+      response = get(BASE_URL, query_parameters)
+
+      if (response.code == 200)
+        users = response["members"].map do |member|
+          name = member["name"]
+          real_name = member["real_name"]
+          slack_id = member["id"]
+          new(name, real_name, slack_id)
+        end
+        return users
+      else
+        raise SlackApiError, "Error #{response.code} : #{response["message"]}"
+      end
+    end
+
+    def display_details
+      info_string = "\nSlack ID : #{slack_id}" +
+                    "\nUsername : #{name}" +
+                    "\nReal name : #{real_name}"
+      return info_string
+    end
+  end
+end
diff --git a/lib/workspace.rb b/lib/workspace.rb
new file mode 100644
index 00000000..3f840c47
--- /dev/null
+++ b/lib/workspace.rb
@@ -0,0 +1,56 @@
+require "httparty"
+require "dotenv"
+require "pry"
+
+Dotenv.load
+
+module SlackCLI
+  class SlackApiError < Exception; end
+
+  class Workspace
+    attr_reader :users, :channels, :selected
+
+    def initialize(users:, channels:)
+      @users = users
+      @channels = channels
+    end
+
+    def display_users
+      return tp users, :name, :real_name, :slack_id
+    end
+
+    def display_channels
+      return tp channels, :slack_id, :name, :members, :topic => { :width => 120 }
+    end
+
+    def select_user(name_or_id)
+      @selected = users.find { |user|
+        user.name == name_or_id
+      }
+
+      @selected ||= users.find { |user|
+        user.slack_id == name_or_id
+      }
+
+      return @selected
+    end
+
+    def select_channel(name_or_id)
+      @selected = channels.find { |channel| channel.name == name_or_id }
+      @selected ||= channels.find { |channel| channel.slack_id == name_or_id }
+      return @selected
+    end
+
+    def show_details
+      selected.display_details
+    end
+
+    def send_message(message)
+      if selected == nil
+        raise SlackApiError, "Invalid recipient"
+      else
+        selected.send_message(message)
+      end
+    end
+  end
+end
diff --git a/specs/channel_spec.rb b/specs/channel_spec.rb
new file mode 100644
index 00000000..bc3db4c0
--- /dev/null
+++ b/specs/channel_spec.rb
@@ -0,0 +1,46 @@
+require_relative "test_helper"
+
+describe "Channel" do
+  let (:channel_data) {
+    {
+      id: "CH2P2QWMR",
+      channel_name: "everyone",
+      topic: "Company-wide announcements and work-based matters",
+      members: 2,
+    }
+  }
+  it "instantiate a channel object" do
+    new_channel = SlackCLI::Channel.new(
+      channel_data[:id],
+      channel_data[:channel_name],
+      channel_data[:topic],
+      channel_data[:members]
+    )
+
+    expect(new_channel).must_be_instance_of SlackCLI::Channel
+  end
+
+  it "has working reader methods" do
+    new_channel = SlackCLI::Channel.new(
+      channel_data[:id],
+      channel_data[:channel_name],
+      channel_data[:topic],
+      channel_data[:members]
+    )
+
+    expect(new_channel.slack_id).must_equal channel_data[:id]
+    expect(new_channel.name).must_equal channel_data[:channel_name]
+    expect(new_channel.topic).must_equal channel_data[:topic]
+    expect(new_channel.members).must_equal channel_data[:members]
+  end
+
+  it "loads array of channels from Slack's API" do
+    VCR.use_cassette("list_channels") do
+      channels = SlackCLI::Channel.get_from_api
+      expect(channels).must_be_instance_of Array
+      channels.each do |channel|
+        expect(channel).must_be_instance_of SlackCLI::Channel
+      end
+    end
+  end
+end
diff --git a/specs/test_helper.rb b/specs/test_helper.rb
index 81ccd06b..d844c0b1 100644
--- a/specs/test_helper.rb
+++ b/specs/test_helper.rb
@@ -1,15 +1,30 @@
-require 'simplecov'
-SimpleCov.start
 
-require 'minitest'
-require 'minitest/autorun'
-require 'minitest/reporters'
-require 'minitest/skip_dsl'
-require 'vcr'
+require "simplecov"
+SimpleCov.start do
+  add_filter %r{^/specs?/}
+  add_filter "slack.rb"
+end
+require "minitest/autorun"
+require "minitest/reporters"
+require "vcr"
+require "webmock/minitest"
+require "dotenv"
+
+Dotenv.load
+
+require_relative "../lib/slack.rb"
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 VCR.configure do |config|
-  config.cassette_library_dir = "specs/cassettes"
-  config.hook_into :webmock
-end
\ No newline at end of file
+  config.cassette_library_dir = "specs/cassettes" # folder where casettes will be located
+  config.hook_into :webmock # tie into this other tool called webmock
+  config.default_cassette_options = {
+    :record => :new_episodes,    # record new data when we don't have it yet
+    :match_requests_on => [:method, :uri, :body], # The http method, URI and body of a request all need to match
+  }
+  # Don't leave our token lying around in a cassette file.
+  config.filter_sensitive_data("<OAUTH_ACCESS_TOKEN>") do
+    ENV["OAUTH_ACCESS_TOKEN"]
+  end
+end
diff --git a/specs/user_spec.rb b/specs/user_spec.rb
new file mode 100644
index 00000000..6f5bcb7c
--- /dev/null
+++ b/specs/user_spec.rb
@@ -0,0 +1,38 @@
+require_relative "test_helper"
+
+describe "User class" do
+  let (:user_data) {
+    {
+      username: "shubharajan",
+      real_name: "Shubha Rajan",
+      slack_id: "ADSHF1324123",
+    }
+  }
+  it "initializes a user class" do
+    new_user = SlackCLI::User.new(user_data[:username],
+                                  user_data[:real_name],
+                                  user_data[:slack_id])
+
+    expect(new_user).must_be_instance_of SlackCLI::User
+  end
+
+  it "has working reader methods" do
+    new_user = SlackCLI::User.new(user_data[:username],
+                                  user_data[:real_name],
+                                  user_data[:slack_id])
+
+    expect(new_user.name).must_equal user_data[:username]
+    expect(new_user.real_name).must_equal user_data[:real_name]
+    expect(new_user.slack_id).must_equal user_data[:slack_id]
+  end
+
+  it "loads array of users from Slack's API" do
+    VCR.use_cassette("list users") do
+      users = SlackCLI::User.get_from_api
+      expect(users).must_be_instance_of Array
+      users.each do |user|
+        expect(user).must_be_instance_of SlackCLI::User
+      end
+    end
+  end
+end
diff --git a/specs/workspace_spec.rb b/specs/workspace_spec.rb
new file mode 100644
index 00000000..b11611d4
--- /dev/null
+++ b/specs/workspace_spec.rb
@@ -0,0 +1,94 @@
+require_relative "test_helper"
+
+describe "Workspace object" do
+  before do
+    VCR.use_cassette("workspace") do
+      @new_workspace = SlackCLI::Workspace.new(
+        users: SlackCLI::User.get_from_api,
+        channels: SlackCLI::Channel.get_from_api,
+      )
+    end
+  end
+
+  it "will initialize a new workspace object" do
+    expect(@new_workspace).must_be_instance_of SlackCLI::Workspace
+  end
+
+  it "selects a user by username" do
+    user = @new_workspace.users.first
+    name = @new_workspace.users.first.name
+    expect(@new_workspace.select_user(name)).must_equal user
+  end
+
+  it "selects a user by id" do
+    user = @new_workspace.users.first
+    id = @new_workspace.users.first.slack_id
+    expect(@new_workspace.select_user(id)).must_equal user
+  end
+
+  it "selects a channel by name" do
+    channel = @new_workspace.channels.first
+    name = @new_workspace.channels.first.name
+    expect(@new_workspace.select_channel(name)).must_equal channel
+  end
+
+  it "selects a channel by id" do
+    channel = @new_workspace.channels.first
+    id = @new_workspace.channels.first.slack_id
+    expect(@new_workspace.select_channel(id)).must_equal channel
+  end
+
+  it "can send a valid message with id to a channel" do
+    VCR.use_cassette("post message") do
+      id = @new_workspace.channels.first.slack_id
+      @new_workspace.select_channel(id)
+      response = @new_workspace.send_message("This is a test!")
+      expect(response).must_equal true
+    end
+  end
+
+  it "can send a valid message with id to a user" do
+    VCR.use_cassette("post message") do
+      id = @new_workspace.users.first.slack_id
+      @new_workspace.select_user(id)
+      response = @new_workspace.send_message("This is a test!")
+      expect(response).must_equal true
+    end
+  end
+
+  it "can send a valid message with name to a channel" do
+    VCR.use_cassette("post message") do
+      name = @new_workspace.channels.first.name
+      @new_workspace.select_channel(name)
+      response = @new_workspace.send_message("This is a test!")
+      expect(response).must_equal true
+    end
+  end
+
+  it "can send a valid message with name to a user" do
+    VCR.use_cassette("post message") do
+      name = @new_workspace.users.first.name
+      @new_workspace.select_user(name)
+      response = @new_workspace.send_message("This is a test!")
+      expect(response).must_equal true
+    end
+  end
+
+  it "will raise an error if the channel is nil or invalid" do
+    VCR.use_cassette("post message") do
+      @new_workspace.select_channel("")
+      expect {
+        @new_workspace.send_message("This is a test!")
+      }.must_raise SlackCLI::SlackApiError
+    end
+  end
+
+  it "will raise an error if the user is nil or invalid" do
+    VCR.use_cassette("post message") do
+      @new_workspace.select_user("")
+      expect {
+        @new_workspace.send_message("This is a test!")
+      }.must_raise SlackCLI::SlackApiError
+    end
+  end
+end