diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08a3b02..0c136cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
 ## [0.1.0] - 2024-10-13
 
 - Initial release v0.1.0
+
+## [0.2.0] - UNRELEASED
+
+- Added check for required environment variables before call to Google Sheets API
diff --git a/Gemfile.lock b/Gemfile.lock
index bee8caf..6c0f877 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    sheet_zoukas (0.1.0)
+    sheet_zoukas (0.2.0)
       google-apis-sheets_v4
 
 GEM
diff --git a/lib/sheet_zoukas.rb b/lib/sheet_zoukas.rb
index fbe41bc..f0a724d 100644
--- a/lib/sheet_zoukas.rb
+++ b/lib/sheet_zoukas.rb
@@ -3,13 +3,17 @@
 require_relative 'sheet_zoukas/data_converter'
 require_relative 'sheet_zoukas/google_sheets'
 require_relative 'sheet_zoukas/version'
+require_relative 'sheet_zoukas/utils'
 
 # Retrieve Google Sheets data
 module SheetZoukas
   class Error < StandardError; end
+  REQUIRED_VARS = %w[GOOGLE_ACCOUNT_TYPE GOOGLE_API_KEY GOOGLE_CLIENT_EMAIL GOOGLE_CLIENT_ID GOOGLE_PRIVATE_KEY].freeze
 
   class << self
     def retrieve_sheet_json(sheet_id, tab_name, range = nil)
+      exit 1 unless SheetZoukas::Utils.vars_present?(REQUIRED_VARS, 'required for Google Sheets API calls')
+
       sheet = GoogleSheets.new
       data = sheet.retrieve_sheet(sheet_id, tab_name, range)
       DataConverter.new(data.values).convert
diff --git a/lib/sheet_zoukas/utils.rb b/lib/sheet_zoukas/utils.rb
new file mode 100644
index 0000000..2100659
--- /dev/null
+++ b/lib/sheet_zoukas/utils.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module SheetZoukas
+  # Utility methods
+  class Utils
+    def self.vars_present?(required_vars, message)
+      all_present = true
+      required_vars.each do |var|
+        if ENV.fetch(var, '').strip.empty?
+          all_present = false
+          puts "⛔️ #{var} #{message}."
+        end
+      end
+      all_present
+    end
+  end
+end
diff --git a/lib/sheet_zoukas/version.rb b/lib/sheet_zoukas/version.rb
index 9d22d16..9e723b3 100644
--- a/lib/sheet_zoukas/version.rb
+++ b/lib/sheet_zoukas/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module SheetZoukas
-  VERSION = '0.1.0'
+  VERSION = '0.2.0'
 end
diff --git a/spec/sheet_zoukas/utils_spec.rb b/spec/sheet_zoukas/utils_spec.rb
new file mode 100644
index 0000000..307a886
--- /dev/null
+++ b/spec/sheet_zoukas/utils_spec.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# rubocop:disable RSpec/MultipleExpectations
+
+require 'spec_helper'
+require 'sheet_zoukas/utils'
+
+RSpec.describe SheetZoukas::Utils do
+  describe '.vars_present?' do
+    before { ENV.store('PRESENT_VAR', 'present') }
+
+    it 'returns false when missing vars' do
+      expect do
+        expect(described_class).not_to be_vars_present(%w[MISSING_VAR PRESENT_VAR], 'is missing')
+      end.to output("⛔️ MISSING_VAR is missing.\n").to_stdout
+    end
+
+    it 'returns true when no missing vars' do
+      expect do
+        expect(described_class).to be_vars_present(%w[PRESENT_VAR], 'is missing')
+      end.not_to output.to_stdout
+    end
+
+    it 'returns false when variable empty string' do
+      ENV.store('EMPTY_VAR', '')
+
+      expect do
+        expect(described_class).not_to be_vars_present(%w[PRESENT_VAR EMPTY_VAR], 'is missing')
+      end.to output("⛔️ EMPTY_VAR is missing.\n").to_stdout
+    end
+
+    it 'returns false when variable blank string' do
+      ENV.store('EMPTY_VAR', '  ')
+
+      expect do
+        expect(described_class).not_to be_vars_present(%w[PRESENT_VAR EMPTY_VAR], 'is missing')
+      end.to output("⛔️ EMPTY_VAR is missing.\n").to_stdout
+    end
+  end
+end
+
+# rubocop:enable RSpec/MultipleExpectations
diff --git a/spec/sheet_zoukas_spec.rb b/spec/sheet_zoukas_spec.rb
index 77dfed8..0cd6725 100644
--- a/spec/sheet_zoukas_spec.rb
+++ b/spec/sheet_zoukas_spec.rb
@@ -20,5 +20,17 @@
                               'Reward Type' => 'no longer active')
       end
     end
+
+    it 'fails when missing required environment variable' do # rubocop:disable RSpec/ExampleLength, RSpec/MultipleExpectations
+      missing = SheetZoukas::REQUIRED_VARS.first
+      ENV.delete(missing)
+      expect do
+        expect do
+          described_class.retrieve_sheet_json(ENV.fetch('GOOGLE_API_SPREADSHEET_ID', nil), 'Log')
+        end.to raise_error(SystemExit) do |error| # rubocop:disable Style/MultilineBlockChain
+          expect(error.status).to eq(1)
+        end
+      end.to output("⛔️ #{missing} required for Google Sheets API calls.\n").to_stdout
+    end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9b4ca16..1d79510 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -30,20 +30,7 @@
   config.filter_sensitive_data('<SPREADSHEET_ID>') { ENV.fetch('GOOGLE_API_SPREADSHEET_ID', nil) }
 end
 
-REQUIRED_VARS = %w[GOOGLE_ACCOUNT_TYPE GOOGLE_API_KEY GOOGLE_CLIENT_EMAIL GOOGLE_CLIENT_ID GOOGLE_PRIVATE_KEY
-                   GOOGLE_API_SPREADSHEET_ID].freeze
-
-def check_vars
-  err = false
-  REQUIRED_VARS.each do |var|
-    if ENV.fetch(var, nil)&.chars
-      puts "✅ #{var}"
-    else
-      err = true
-      puts "⛔️ #{var} required for tests to run."
-    end
-  end
-  exit 1 if err
-end
-
-check_vars
+# make sure all vars required for testing are present
+require 'sheet_zoukas/utils'
+REQUIRED_VARS_TEST = (SheetZoukas::REQUIRED_VARS + ['GOOGLE_API_SPREADSHEET_ID']).freeze
+exit 1 unless SheetZoukas::Utils.vars_present?(REQUIRED_VARS_TEST, 'required for tests to run')