diff --git a/spring-boot/spring-boot-codefirst/.gitignore b/spring-boot/spring-boot-codefirst/.gitignore
new file mode 100644
index 0000000..6c01878
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/.gitignore
@@ -0,0 +1,32 @@
+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
diff --git a/spring-boot/spring-boot-codefirst/build.gradle b/spring-boot/spring-boot-codefirst/build.gradle
new file mode 100644
index 0000000..018cb68
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/build.gradle
@@ -0,0 +1,34 @@
+plugins {
+    id 'org.springframework.boot' version '2.3.0.RELEASE'
+    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+    id 'java'
+}
+
+group = 'io.reflectoring'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '1.8'
+
+configurations {
+    compileOnly {
+        extendsFrom annotationProcessor
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.boot:spring-boot-starter-security'
+    implementation 'org.springdoc:springdoc-openapi-ui:1.3.3'
+    compileOnly 'org.projectlombok:lombok'
+    annotationProcessor 'org.projectlombok:lombok'
+    testImplementation('org.springframework.boot:spring-boot-starter-test') {
+        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+    }
+}
+
+test {
+    useJUnitPlatform()
+}
diff --git a/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.jar b/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..f3d88b1
Binary files /dev/null and b/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.properties b/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..1690f2d
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Wed Apr 29 20:01:41 CEST 2020
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
diff --git a/spring-boot/spring-boot-codefirst/gradlew b/spring-boot/spring-boot-codefirst/gradlew
new file mode 100644
index 0000000..536f027
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/gradlew
@@ -0,0 +1,183 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ]; do
+  ls=$(ls -ld "$PRG")
+  link=$(expr "$ls" : '.*-> \(.*\)$')
+  if expr "$link" : '/.*' >/dev/null; then
+    PRG="$link"
+  else
+    PRG=$(dirname "$PRG")"/$link"
+  fi
+done
+SAVED="$(pwd)"
+cd "$(dirname \"$PRG\")/" >/dev/null
+APP_HOME="$(pwd -P)"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=$(basename "$0")
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn() {
+  echo "$*"
+}
+
+die() {
+  echo
+  echo "$*"
+  echo
+  exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$(uname)" in
+CYGWIN*)
+  cygwin=true
+  ;;
+Darwin*)
+  darwin=true
+  ;;
+MINGW*)
+  msys=true
+  ;;
+NONSTOP*)
+  nonstop=true
+  ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ]; then
+  if [ -x "$JAVA_HOME/jre/sh/java" ]; then
+    # IBM's JDK on AIX uses strange locations for the executables
+    JAVACMD="$JAVA_HOME/jre/sh/java"
+  else
+    JAVACMD="$JAVA_HOME/bin/java"
+  fi
+  if [ ! -x "$JAVACMD" ]; then
+    die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+  fi
+else
+  JAVACMD="java"
+  which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ]; then
+  MAX_FD_LIMIT=$(ulimit -H -n)
+  if [ $? -eq 0 ]; then
+    if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ]; then
+      MAX_FD="$MAX_FD_LIMIT"
+    fi
+    ulimit -n $MAX_FD
+    if [ $? -ne 0 ]; then
+      warn "Could not set maximum file descriptor limit: $MAX_FD"
+    fi
+  else
+    warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+  fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+  GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ]; then
+  APP_HOME=$(cygpath --path --mixed "$APP_HOME")
+  CLASSPATH=$(cygpath --path --mixed "$CLASSPATH")
+  JAVACMD=$(cygpath --unix "$JAVACMD")
+
+  # We build the pattern for arguments to be converted via cygpath
+  ROOTDIRSRAW=$(find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null)
+  SEP=""
+  for dir in $ROOTDIRSRAW; do
+    ROOTDIRS="$ROOTDIRS$SEP$dir"
+    SEP="|"
+  done
+  OURCYGPATTERN="(^($ROOTDIRS))"
+  # Add a user-defined pattern to the cygpath arguments
+  if [ "$GRADLE_CYGPATTERN" != "" ]; then
+    OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+  fi
+  # Now convert the arguments - kludge to limit ourselves to /bin/sh
+  i=0
+  for arg in "$@"; do
+    CHECK=$(echo "$arg" | egrep -c "$OURCYGPATTERN" -)
+    CHECK2=$(echo "$arg" | egrep -c "^-") ### Determine if an option
+
+    if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ]; then ### Added a condition
+      eval $(echo args$i)=$(cygpath --path --ignore --mixed "$arg")
+    else
+      eval $(echo args$i)="\"$arg\""
+    fi
+    i=$(expr $i + 1)
+  done
+  case $i in
+  0) set -- ;;
+  1) set -- "$args0" ;;
+  2) set -- "$args0" "$args1" ;;
+  3) set -- "$args0" "$args1" "$args2" ;;
+  4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+  5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+  6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+  7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+  8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+  9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+  esac
+fi
+
+# Escape application args
+save() {
+  for i; do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/"; done
+  echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/spring-boot/spring-boot-codefirst/gradlew.bat b/spring-boot/spring-boot-codefirst/gradlew.bat
new file mode 100644
index 0000000..62bd9b9
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/gradlew.bat
@@ -0,0 +1,103 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/spring-boot/spring-boot-codefirst/settings.gradle b/spring-boot/spring-boot-codefirst/settings.gradle
new file mode 100644
index 0000000..804af7d
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/settings.gradle
@@ -0,0 +1 @@
+rootProject.name = 'code-first'
diff --git a/spring-boot/spring-boot-codefirst/src/main/java/io/reflectoring/codefirst/CodeFirstApplication.java b/spring-boot/spring-boot-codefirst/src/main/java/io/reflectoring/codefirst/CodeFirstApplication.java
new file mode 100644
index 0000000..389bfc7
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/src/main/java/io/reflectoring/codefirst/CodeFirstApplication.java
@@ -0,0 +1,160 @@
+package io.reflectoring.codefirst;
+
+import io.swagger.v3.oas.annotations.OpenAPIDefinition;
+import io.swagger.v3.oas.annotations.enums.SecuritySchemeIn;
+import io.swagger.v3.oas.annotations.enums.SecuritySchemeType;
+import io.swagger.v3.oas.annotations.info.Contact;
+import io.swagger.v3.oas.annotations.info.Info;
+import io.swagger.v3.oas.annotations.info.License;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
+import io.swagger.v3.oas.annotations.security.SecurityScheme;
+import io.swagger.v3.oas.annotations.servers.Server;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.web.bind.annotation.*;
+
+import javax.annotation.PostConstruct;
+import java.util.List;
+import java.util.UUID;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+
+@SpringBootApplication
+public class CodeFirstApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(CodeFirstApplication.class, args);
+    }
+}
+
+@RequestMapping("/api/todos")
+@Tag(name = "Todo API", description = "euismod in pellentesque massa placerat duis ultricies lacus sed turpis")
+@SecurityRequirement(name = "api")
+interface TodoApi {
+
+    @GetMapping
+    @ResponseStatus(code = HttpStatus.OK)
+    List<Todo> findAll();
+
+    @GetMapping("/{id}")
+    @ResponseStatus(code = HttpStatus.OK)
+    Todo findById(@PathVariable String id);
+
+    @PostMapping
+    @ResponseStatus(code = HttpStatus.CREATED)
+    Todo save(@RequestBody Todo todo);
+
+    @PutMapping("/{id}")
+    @ResponseStatus(code = HttpStatus.OK)
+    Todo update(@PathVariable String id, @RequestBody Todo todo);
+
+    @DeleteMapping("/{id}")
+    @ResponseStatus(code = HttpStatus.NO_CONTENT)
+    void delete(@PathVariable String id);
+}
+
+@OpenAPIDefinition(
+        info = @Info(
+                title = "Code-First Approach (reflectoring.io)",
+                description = "" +
+                        "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur et rhoncus quam. Aenean quis augue ac eros pulvinar malesuada. " +
+                        "In sagittis elit egestas tincidunt iaculis. " +
+                        "Donec eu lacus vitae nulla varius consectetur a vel quam. Aliquam erat volutpat. Duis eget ullamcorper tellus",
+                contact = @Contact(name = "Reflectoring", url = "https://reflectoring.io", email = "petros.stergioulas94@gmail.com"),
+                license = @License(name = "MIT Licence", url = "https://github.com/thombergs/code-examples/blob/master/LICENSE")),
+        servers = @Server(url = "http://localhost:8080")
+)
+@SecurityScheme(name = "api", scheme = "basic", type = SecuritySchemeType.HTTP, in = SecuritySchemeIn.HEADER)
+class OpenAPIConfiguration {
+}
+
+@EnableWebSecurity
+class SecurityConfiguration extends WebSecurityConfigurerAdapter {
+
+    @Override
+    protected void configure(HttpSecurity http) throws Exception {
+        http.authorizeRequests()
+                .antMatchers("/unsecured", "/swagger-ui/**", "/reflectoring-openapi/**").permitAll()
+                .anyRequest().authenticated()
+                .and()
+                .httpBasic();
+    }
+
+    @Override
+    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+        auth.inMemoryAuthentication()
+                .withUser("admin")
+                .password(passwordEncoder().encode("password"))
+                .authorities("ADMIN");
+    }
+
+    @Bean
+    public PasswordEncoder passwordEncoder() {
+        return new BCryptPasswordEncoder();
+    }
+}
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+class Todo {
+    private String id;
+    private String text;
+}
+
+@RestController
+class TodoController implements TodoApi {
+
+    private List<Todo> todos;
+
+    @Override
+    public List<Todo> findAll() {
+        return todos;
+    }
+
+    @Override
+    public Todo findById(String id) {
+        return todos.stream().filter(todo -> todo.getId().equals(id)).findFirst().orElseGet(null);
+    }
+
+    @Override
+    public Todo save(Todo todo) {
+        todos.add(todo);
+        return todo;
+    }
+
+    @Override
+    public Todo update(String id, Todo todo) {
+        for (Todo t : todos) {
+            if (t.getId().equals(id)) {
+                t.setText(todo.getText());
+            }
+        }
+
+        return todo;
+    }
+
+    @Override
+    public void delete(String id) {
+        todos.removeIf(t -> t.getId().equals(id));
+    }
+
+    @PostConstruct
+    public void onInit() {
+        todos = Stream.of("Groceries", "Lisa's birthday")
+                .map(todo -> new Todo(UUID.randomUUID().toString(), todo))
+                .collect(Collectors.toList());
+    }
+}
\ No newline at end of file
diff --git a/spring-boot/spring-boot-codefirst/src/main/resources/application.yml b/spring-boot/spring-boot-codefirst/src/main/resources/application.yml
new file mode 100644
index 0000000..3726e11
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/src/main/resources/application.yml
@@ -0,0 +1,3 @@
+springdoc:
+  api-docs:
+    path: /reflectoring-openapi
diff --git a/spring-boot/spring-boot-codefirst/src/test/java/io/reflectoring/codefirst/CodeFirstApplicationTests.java b/spring-boot/spring-boot-codefirst/src/test/java/io/reflectoring/codefirst/CodeFirstApplicationTests.java
new file mode 100644
index 0000000..b0a838e
--- /dev/null
+++ b/spring-boot/spring-boot-codefirst/src/test/java/io/reflectoring/codefirst/CodeFirstApplicationTests.java
@@ -0,0 +1,13 @@
+package io.reflectoring.codefirst;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class CodeFirstApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}