diff --git a/lib/html_proofer.rb b/lib/html_proofer.rb
index ca79c06e..1790aa16 100644
--- a/lib/html_proofer.rb
+++ b/lib/html_proofer.rb
@@ -25,7 +25,7 @@ def check_file(file, options = {})
       raise ArgumentError unless file.is_a?(String)
       raise ArgumentError, "#{file} does not exist" unless File.exist?(file)
 
-      options[:type] = :file
+      options = prepare_options(options, :file)
       HTMLProofer::Runner.new(file, options)
     end
 
@@ -33,14 +33,14 @@ def check_directory(directory, options = {})
       raise ArgumentError unless directory.is_a?(String)
       raise ArgumentError, "#{directory} does not exist" unless Dir.exist?(directory)
 
-      options[:type] = :directory
+      options = prepare_options(options, :directory)
       HTMLProofer::Runner.new([directory], options)
     end
 
     def check_directories(directories, options = {})
       raise ArgumentError unless directories.is_a?(Array)
 
-      options[:type] = :directory
+      options = prepare_options(options, :directory)
       directories.each do |directory|
         raise ArgumentError, "#{directory} does not exist" unless Dir.exist?(directory)
       end
@@ -50,9 +50,20 @@ def check_directories(directories, options = {})
     def check_links(links, options = {})
       raise ArgumentError unless links.is_a?(Array)
 
-      options[:type] = :links
+      options = prepare_options(options, :links)
       HTMLProofer::Runner.new(links, options)
     end
+
+    private
+
+    def prepare_options(options, type)
+      options = {} if options.nil?
+
+      raise ArgumentError, "Options must be a Hash" unless options.is_a?(Hash)
+
+      options[:type] = type
+      options
+    end
   end
 end
 
diff --git a/lib/html_proofer/configuration.rb b/lib/html_proofer/configuration.rb
index e49d6ede..a5593b49 100644
--- a/lib/html_proofer/configuration.rb
+++ b/lib/html_proofer/configuration.rb
@@ -49,6 +49,8 @@ module Configuration
 
     class << self
       def generate_defaults(opts)
+        validate_options(default_options, opts)
+
         options = PROOFER_DEFAULTS.merge(opts)
 
         options[:typhoeus] = HTMLProofer::Configuration::TYPHOEUS_DEFAULTS.merge(opts[:typhoeus] || {})
@@ -86,6 +88,24 @@ def parse_json_option(option_name, config, symbolize_names: true)
           raise ArgumentError, "Option '#{option_name} did not contain valid JSON."
         end
       end
+
+      private
+
+      def default_options
+        PROOFER_DEFAULTS.merge(typhoeus: TYPHOEUS_DEFAULTS).merge(hydra: HYDRA_DEFAULTS).merge(parallel: PARALLEL_DEFAULTS)
+      end
+
+      def validate_options(defaults, options)
+        defaults.each do |key, default_value|
+          next unless options.key?(key)
+
+          value = options[key]
+          raise TypeError, "Invalid value for '#{key}': '#{value}'. Expected #{default_value.class}." unless value.is_a?(default_value.class)
+
+          # Iterate over nested hashes
+          validate_options(default_value, value) if default_value.is_a?(Hash)
+        end
+      end
     end
   end
 end
diff --git a/spec/html-proofer/proofer_spec.rb b/spec/html-proofer/proofer_spec.rb
index ba1e7260..433e90ba 100644
--- a/spec/html-proofer/proofer_spec.rb
+++ b/spec/html-proofer/proofer_spec.rb
@@ -44,6 +44,29 @@
         typhoeus: { verbose: true, headers: { "User-Agent" => "Mozilla/5.0 (compatible; My New User-Agent)" } })
       expect(http["request"]["headers"]["User-Agent"]).to(eq(["Mozilla/5.0 (compatible; My New User-Agent)"]))
     end
+
+    it "does not fail on nil options" do
+      github_hash = File.join(FIXTURES_DIR, "links", "github_hash.html")
+      HTMLProofer.check_file(github_hash, nil)
+    end
+
+    it "fails with friendly error on non-Hash options" do
+      links_dir = File.join(FIXTURES_DIR, "links")
+      expect { HTMLProofer.check_directory(links_dir, "abc") }.to(raise_error(ArgumentError, "Options must be a Hash"))
+    end
+
+    it "fails with friendly error invalid option values" do
+      options = {
+        assume_extension: true,
+        typhoeus: "abc",
+        enforce_https: :yes_please,
+        hydra: { max_concurrency: false },
+      }
+      options.each do |key, value|
+        links_dir = File.join(FIXTURES_DIR, "links")
+        expect { HTMLProofer.check_directory(links_dir, key => value).run }.to(raise_error(TypeError, /^Invalid value for '.*': '.*'\. Expected .*\./))
+      end
+    end
   end
 
   describe "file ignores" do