diff --git a/.ci/check_style.sh b/.ci/check_style.sh
new file mode 100755
index 00000000..ed6fa4f4
--- /dev/null
+++ b/.ci/check_style.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env sh
+set -evx
+
+clang-format --version
+
+git ls-files -- '*.cpp' '*.hpp' | xargs clang-format -i -style=file
+
+git diff --exit-code --color
+
+mkdir build || true
+cd build
+CXX_FLAGS="-Werror -Wall -Wextra -pedantic -std=c++11" cmake .. -DCLANG_TIDY_FIX=ON
+cmake --build .
+
+git diff --exit-code --color
+
+set +evx
diff --git a/.ci/prepare_altern.sh b/.ci/prepare_altern.sh
index 24f63777..e384b003 100644
--- a/.ci/prepare_altern.sh
+++ b/.ci/prepare_altern.sh
@@ -9,6 +9,8 @@ if [ "$CXX" = "g++" ] ; then
 else
     ln -s `which clang-$COMPILER` clang
     ln -s `which clang++-$COMPILER` clang++
+    ln -s `which clang-format-$COMPILER` clang-format
+    ln -s `which clang-tidy-$COMPILER` clang-tidy
 fi
 
 export PATH="${DEPS_DIR}/extrabin":$PATH
diff --git a/.ci/travis.sh b/.ci/travis.sh
index 66f6192f..c2108d3d 100755
--- a/.ci/travis.sh
+++ b/.ci/travis.sh
@@ -6,3 +6,5 @@ cd build
 cmake .. -DCLI_SINGLE_FILE_TESTS=ON -DCMAKE_BUILD_TYPE=Debug
 cmake --build . -- -j2
 ctest --output-on-failure
+
+set +evx
diff --git a/.travis.yml b/.travis.yml
index 4bc76b85..e95a33be 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,9 +13,16 @@ matrix:
   - compiler: clang
     addons:
       apt:
-        sources:
-        - llvm-toolchain-precise-3.5
-        - ubuntu-toolchain-r-test
+        packages:
+        - clang-3.9
+        - clang-format-3.9
+        - clang-tidy-3.9
+    env:
+    - COMPILER=3.9
+    - CHECK_STYLE=yes
+  - compiler: clang
+    addons:
+      apt:
         packages:
         - clang-3.5
     env:
@@ -37,8 +44,6 @@ matrix:
   - compiler: gcc
     addons:
       apt:
-        sources:
-        - ubuntu-toolchain-r-test
         packages:
         - g++-4.7
     env:
@@ -48,19 +53,21 @@ matrix:
 install:
 - python -c 'import sys; print(sys.version_info[:])'
 - DEPS_DIR="${TRAVIS_BUILD_DIR}/deps"
-- if [ "$TRAVIS_OS_NAME" = "linux" ]; then cd $TRAVIS_BUILD_DIR && . .ci/prepare_altern.sh
-  ; fi
-- if [ "$TRAVIS_OS_NAME" = "linux" ] ; then cd $TRAVIS_BUILD_DIR && . .ci/build_cmake.sh
-  ; fi
-- if [ "$TRAVIS_OS_NAME" = "linux" ] ; then cd $TRAVIS_BUILD_DIR && . .ci/build_doxygen.sh
-  ; fi
+- if [ "$TRAVIS_OS_NAME" = "linux" ]; then cd $TRAVIS_BUILD_DIR && . .ci/prepare_altern.sh ; fi
+- if [ "$TRAVIS_OS_NAME" = "linux" ] ; then cd $TRAVIS_BUILD_DIR && . .ci/build_cmake.sh ; fi
+- if [ "$TRAVIS_OS_NAME" = "linux" ] ; then cd $TRAVIS_BUILD_DIR && . .ci/build_doxygen.sh ; fi
 - if [ -n "$COVERALLS" ] ; then cd $TRAVIS_BUILD_DIR && . .ci/build_lcov.sh ; fi
 - cd "${DEPS_DIR}"
-- if [ "$(python -c 'import sys; print(sys.version_info[0])')" = "2" ] ; then pip
-  install --user pathlib; fi
+- if [ "$(python -c 'import sys; print(sys.version_info[0])')" = "2" ] ; then pip install --user pathlib ; fi
 script:
 - cd "${TRAVIS_BUILD_DIR}"
-- .ci/travis.sh
+- |
+  if [ -n "$CHECK_STYLE" ]
+  then
+    .ci/check_style.sh
+  else
+    .ci/travis.sh
+  fi
 after_success:
 - if [ -n "$COVERALLS" ] ; then cd $TRAVIS_BUILD_DIR && .ci/run_codecov.sh ; fi
 - echo "${TRAVIS_BRANCH}"
@@ -68,7 +75,7 @@ after_success:
 - |
   if [ "${TRAVIS_BRANCH}" == "master" ] && [ "${TRAVIS_PULL_REQUEST}" == "false" ] && [ -n "$DEPLOY_MAT" ]
   then
-      echo "Updating docs" && cd $TRAVIS_BUILD_DIR && .ci/build_docs.sh
+    echo "Updating docs" && cd $TRAVIS_BUILD_DIR && .ci/build_docs.sh
   fi
 deploy:
   provider: releases
diff --git a/examples/enum.cpp b/examples/enum.cpp
index ce97db39..c03799cf 100644
--- a/examples/enum.cpp
+++ b/examples/enum.cpp
@@ -1,12 +1,8 @@
 #include <CLI/CLI.hpp>
 
-enum Level : std::int32_t {
-    High,
-    Medium,
-    Low
-};
+enum Level : std::int32_t { High, Medium, Low };
 
-int main(int argc, char** argv) {
+int main(int argc, char **argv) {
     CLI::App app;
 
     Level level;
@@ -15,9 +11,8 @@ int main(int argc, char** argv) {
 
     try {
         app.parse(argc, argv);
-    } catch (CLI::Error const& e) {
+    } catch(CLI::Error const &e) {
         app.exit(e);
     }
     return 0;
 }
-
diff --git a/examples/prefix_command.cpp b/examples/prefix_command.cpp
index 103ee833..dcf4f7ff 100644
--- a/examples/prefix_command.cpp
+++ b/examples/prefix_command.cpp
@@ -6,8 +6,7 @@ int main(int argc, char **argv) {
     app.prefix_command();
 
     std::vector<int> vals;
-    app.add_option("--vals,-v", vals)
-        ->expected(1);
+    app.add_option("--vals,-v", vals)->expected(1);
 
     std::vector<std::string> more_comms;
     try {
@@ -19,7 +18,7 @@ int main(int argc, char **argv) {
     std::cout << "Prefix:";
     for(int v : vals)
         std::cout << v << ":";
-    
+
     std::cout << std::endl << "Remaining commands: ";
 
     // Perfer to loop over from beginning, not "pop" order
diff --git a/include/CLI/App.hpp b/include/CLI/App.hpp
index 9ab4cd6a..cedef560 100644
--- a/include/CLI/App.hpp
+++ b/include/CLI/App.hpp
@@ -59,7 +59,7 @@ class App {
 
     ///  If true, return immediatly on an unrecognised option (implies allow_extras)
     bool prefix_command_{false};
-    
+
     /// This is a function that runs when complete. Great for subcommands. Can throw.
     std::function<void()> callback_;
 
@@ -160,7 +160,7 @@ class App {
         prefix_command_ = allow;
         return this;
     }
-    
+
     /// Ignore case. Subcommand inherit value.
     App *ignore_case(bool value = true) {
         ignore_case_ = value;
@@ -225,8 +225,6 @@ class App {
         } else
             throw OptionAlreadyAdded(myopt.get_name());
     }
-    
-    
 
     /// Add option for non-vectors (duplicate copy needed without defaulted to avoid `iostream << value`)
     template <typename T, enable_if_t<!is_vector<T>::value, detail::enabler> = detail::dummy>
@@ -251,13 +249,13 @@ class App {
                        T &variable, ///< The variable to set
                        std::string description,
                        bool defaulted) {
-        
+
         CLI::callback_t fun = [&variable](CLI::results_t res) {
             if(res.size() != 1)
                 return false;
             return detail::lexical_cast(res[0], variable);
         };
-        
+
         Option *opt = add_option(name, fun, description, defaulted);
         opt->set_custom_option(detail::type_name<T>());
         if(defaulted) {
@@ -267,13 +265,13 @@ class App {
         }
         return opt;
     }
-    
+
     /// Add option for vectors (no default)
     template <typename T>
     Option *add_option(std::string name,
                        std::vector<T> &variable, ///< The variable vector to set
                        std::string description = "") {
-        
+
         CLI::callback_t fun = [&variable](CLI::results_t res) {
             bool retval = true;
             variable.clear();
@@ -283,12 +281,12 @@ class App {
             }
             return (!variable.empty()) && retval;
         };
-        
+
         Option *opt = add_option(name, fun, description, false);
         opt->set_custom_option(detail::type_name<T>(), -1, true);
         return opt;
     }
-    
+
     /// Add option for vectors
     template <typename T>
     Option *add_option(std::string name,
@@ -386,7 +384,7 @@ class App {
         opt->set_custom_option(typeval);
         return opt;
     }
-    
+
     /// Add set of options
     template <typename T>
     Option *add_set(std::string name,
@@ -394,7 +392,7 @@ class App {
                     std::set<T> options, ///< The set of posibilities
                     std::string description,
                     bool defaulted) {
-        
+
         CLI::callback_t fun = [&member, options](CLI::results_t res) {
             if(res.size() != 1) {
                 return false;
@@ -404,7 +402,7 @@ class App {
                 return false;
             return std::find(std::begin(options), std::end(options), member) != std::end(options);
         };
-        
+
         Option *opt = add_option(name, fun, description, defaulted);
         std::string typeval = detail::type_name<T>();
         typeval += " in {" + detail::join(options) + "}";
@@ -443,17 +441,17 @@ class App {
         std::string typeval = detail::type_name<std::string>();
         typeval += " in {" + detail::join(options) + "}";
         opt->set_custom_option(typeval);
-        
+
         return opt;
     }
-    
+
     /// Add set of options, string only, ignore case
     Option *add_set_ignore_case(std::string name,
                                 std::string &member,           ///< The selected member of the set
                                 std::set<std::string> options, ///< The set of posibilities
                                 std::string description,
                                 bool defaulted) {
-        
+
         CLI::callback_t fun = [&member, options](CLI::results_t res) {
             if(res.size() != 1) {
                 return false;
@@ -469,7 +467,7 @@ class App {
                 return true;
             }
         };
-        
+
         Option *opt = add_option(name, fun, description, defaulted);
         std::string typeval = detail::type_name<std::string>();
         typeval += " in {" + detail::join(options) + "}";
@@ -912,19 +910,19 @@ class App {
                 char *buffer = nullptr;
                 std::string ename_string;
 
-                #ifdef _MSC_VER
+#ifdef _MSC_VER
                 // Windows version
                 size_t sz = 0;
                 if(_dupenv_s(&buffer, &sz, opt->envname_.c_str()) == 0 && buffer != nullptr) {
                     ename_string = std::string(buffer);
                     free(buffer);
                 }
-                #else
+#else
                 // This also works on Windows, but gives a warning
                 buffer = std::getenv(opt->envname_.c_str());
                 if(buffer != nullptr)
                     ename_string = std::string(buffer);
-                #endif
+#endif
 
                 if(!ename_string.empty()) {
                     opt->add_result(ename_string);
@@ -1068,10 +1066,8 @@ class App {
     size_t _count_remaining_required_positionals() const {
         size_t retval = 0;
         for(const Option_p &opt : options_)
-            if(opt->get_positional()
-               && opt->get_required()
-               && opt->get_expected() > 0
-               && static_cast<int>(opt->count()) < opt->get_expected())
+            if(opt->get_positional() && opt->get_required() && opt->get_expected() > 0 &&
+               static_cast<int>(opt->count()) < opt->get_expected())
                 retval = static_cast<size_t>(opt->get_expected()) - opt->count();
 
         return retval;
@@ -1098,7 +1094,7 @@ class App {
         else {
             args.pop_back();
             missing()->emplace_back(detail::Classifer::NONE, positional);
-            
+
             if(prefix_command_) {
                 while(!args.empty()) {
                     missing()->emplace_back(detail::Classifer::NONE, args.back());
@@ -1106,7 +1102,6 @@ class App {
                 }
             }
         }
-        
     }
 
     /// Parse a subcommand, modify args and continue
diff --git a/include/CLI/Option.hpp b/include/CLI/Option.hpp
index ee74929a..7dbe40d1 100644
--- a/include/CLI/Option.hpp
+++ b/include/CLI/Option.hpp
@@ -433,9 +433,8 @@ class Option {
     /// Set the default value string representation
     void set_default_val(std::string val) { defaultval_ = val; }
 
-
     /// Set the type name displayed on this option
-    void set_type_name(std::string val) {typeval_ = val;}
+    void set_type_name(std::string val) { typeval_ = val; }
 
     ///@}
 
diff --git a/include/CLI/TypeTools.hpp b/include/CLI/TypeTools.hpp
index e43d1e2c..42140924 100644
--- a/include/CLI/TypeTools.hpp
+++ b/include/CLI/TypeTools.hpp
@@ -75,9 +75,8 @@ constexpr const char *type_name() {
 // Lexical cast
 
 /// Integers / enums
-template <typename T, enable_if_t<std::is_integral<T>::value
-    || std::is_enum<T>::value
-    , detail::enabler> = detail::dummy>
+template <typename T,
+          enable_if_t<std::is_integral<T>::value || std::is_enum<T>::value, detail::enabler> = detail::dummy>
 bool lexical_cast(std::string input, T &output) {
     try {
         output = static_cast<T>(std::stoll(input));
@@ -103,11 +102,9 @@ bool lexical_cast(std::string input, T &output) {
 }
 
 /// String and similar
-template <
-    typename T,
-    enable_if_t<!std::is_floating_point<T>::value
-                && !std::is_integral<T>::value
-                && !std::is_enum<T>::value, detail::enabler> = detail::dummy>
+template <typename T,
+          enable_if_t<!std::is_floating_point<T>::value && !std::is_integral<T>::value && !std::is_enum<T>::value,
+                      detail::enabler> = detail::dummy>
 bool lexical_cast(std::string input, T &output) {
     output = input;
     return true;
diff --git a/tests/AppTest.cpp b/tests/AppTest.cpp
index dd9a3684..2ddb4be7 100644
--- a/tests/AppTest.cpp
+++ b/tests/AppTest.cpp
@@ -204,34 +204,25 @@ TEST_F(TApp, DefaultOpts) {
 }
 
 TEST_F(TApp, EnumTest) {
-    enum Level : std::int32_t {
-        High,
-        Medium,
-        Low
-    };
+    enum Level : std::int32_t { High, Medium, Low };
     Level level = Level::Low;
     app.add_option("--level", level);
-    
+
     args = {"--level", "1"};
     run();
     EXPECT_EQ(level, Level::Medium);
 }
 
 TEST_F(TApp, NewEnumTest) {
-    enum class Level2 : std::int32_t {
-        High,
-        Medium,
-        Low
-    };
+    enum class Level2 : std::int32_t { High, Medium, Low };
     Level2 level = Level2::Low;
     app.add_option("--level", level);
-    
+
     args = {"--level", "1"};
     run();
     EXPECT_EQ(level, Level2::Medium);
 }
 
-
 TEST_F(TApp, RequiredFlags) {
     app.add_flag("-a")->required();
     app.add_flag("-b")->mandatory(); // Alternate term
@@ -440,7 +431,6 @@ TEST_F(TApp, InSetWithDefault) {
     EXPECT_THROW(run(), CLI::ConversionError);
 }
 
-
 TEST_F(TApp, InCaselessSetWithDefault) {
 
     std::string choice = "one";
@@ -532,7 +522,6 @@ TEST_F(TApp, VectorFixedString) {
     EXPECT_EQ(answer, strvec);
 }
 
-
 TEST_F(TApp, VectorDefaultedFixedString) {
     std::vector<std::string> strvec{"one"};
     std::vector<std::string> answer{"mystring", "mystring2", "mystring3"};
@@ -895,40 +884,40 @@ TEST_F(TApp, CheckSubcomFail) {
 
 // Added to test defaults on dual method
 TEST_F(TApp, OptionWithDefaults) {
-    int someint=2;
+    int someint = 2;
     app.add_option("-a", someint, "", true);
-    
+
     args = {"-a1", "-a2"};
-    
+
     EXPECT_THROW(run(), CLI::ConversionError);
 }
 
 // Added to test defaults on dual method
 TEST_F(TApp, SetWithDefaults) {
-    int someint=2;
-    app.add_set("-a", someint, {1,2,3,4}, "", true);
-    
+    int someint = 2;
+    app.add_set("-a", someint, {1, 2, 3, 4}, "", true);
+
     args = {"-a1", "-a2"};
-    
+
     EXPECT_THROW(run(), CLI::ConversionError);
 }
 
 // Added to test defaults on dual method
 TEST_F(TApp, SetWithDefaultsConversion) {
-    int someint=2;
-    app.add_set("-a", someint, {1,2,3,4}, "", true);
-    
+    int someint = 2;
+    app.add_set("-a", someint, {1, 2, 3, 4}, "", true);
+
     args = {"-a", "hi"};
-    
+
     EXPECT_THROW(run(), CLI::ConversionError);
 }
 
 // Added to test defaults on dual method
 TEST_F(TApp, SetWithDefaultsIC) {
-    std::string someint="ho";
+    std::string someint = "ho";
     app.add_set_ignore_case("-a", someint, {"Hi", "Ho"}, "", true);
-    
+
     args = {"-aHi", "-aHo"};
-    
+
     EXPECT_THROW(run(), CLI::ConversionError);
 }
diff --git a/tests/SubcommandTest.cpp b/tests/SubcommandTest.cpp
index 21c26c28..6e2e7e05 100644
--- a/tests/SubcommandTest.cpp
+++ b/tests/SubcommandTest.cpp
@@ -307,16 +307,15 @@ TEST_F(TApp, BadSubcomSearch) {
 }
 
 TEST_F(TApp, PrefixProgram) {
-    
+
     app.prefix_command();
-    
+
     app.add_flag("--simple");
-    
+
     args = {"--simple", "other", "--simple", "--mine"};
     auto ret_args = run();
-    
+
     EXPECT_EQ(ret_args, std::vector<std::string>({"--mine", "--simple", "other"}));
-    
 }
 
 struct SubcommandProgram : public TApp {