diff --git a/src/build/cli.cr b/src/build/cli.cr
index 8cdb4dc..b957f60 100644
--- a/src/build/cli.cr
+++ b/src/build/cli.cr
@@ -16,12 +16,16 @@ module DocMachine::Build
         opts.separator ""
         opts.separator "Builder Options:"
 
+        opts.on("-a", "--action ACTION", "Action (watch, build, shell, etc.)") do |action|
+          config.action = action
+        end
+
         opts.on("-d", "--data-dir DIR", "Content directory") do |dir|
           config.data_dir = dir
         end
 
-        opts.on("-a", "--action ACTION", "Action (watch, build, shell, etc.)") do |action|
-          config.action = action
+        opts.on("-p", "--port PORT", "Set base port to PORT") do |port|
+          config.port = port.to_i
         end
 
         opts.on("-t", "--tty", "Enable TTY mode (needed for shell)") do
diff --git a/src/build/config.cr b/src/build/config.cr
index 3c1b2e5..8129259 100644
--- a/src/build/config.cr
+++ b/src/build/config.cr
@@ -4,6 +4,7 @@ module DocMachine::Build
     property data_dir : String = Dir.current
     property action : String = "watch"
     property enable_tty : Bool = false
+    property port : Int32 = 5100
 
     def initialize(@parent : DocMachine::Config)
     end
diff --git a/src/build/run.cr b/src/build/run.cr
index 0d1c5d0..af91688 100644
--- a/src/build/run.cr
+++ b/src/build/run.cr
@@ -30,6 +30,17 @@ module DocMachine::Build
       self._pull_image()
     end
 
+    private def _find_port(port_base)
+      (port_base..65535).each do |port|
+        return port if _port_available?(port)
+      end
+      raise "No port available"
+    end
+
+    private def _port_available?(port)
+      true
+    end
+
     private def _avoid_duplicates
       docker_cid = %x{docker ps -f "name=#{@docker_name}" -q}.strip
 
@@ -119,7 +130,7 @@ module DocMachine::Build
 
       ## Detect Mkdocs configuration - old format (full)
       if File.exists?("#{@config.data_dir}/mkdocs.yml")
-        Log.info { "Mkdocs: detected mkdocs.yml file. Please rename to mkdocs-patch.yml" }
+        Log.info { "Docs: detected mkdocs.yml file. Please rename to mkdocs-patch.yml" }
         exit 1
       end
 
@@ -127,27 +138,33 @@ module DocMachine::Build
       if File.exists?("#{@config.data_dir}/mkdocs-patch.yml")
         docker_opt_mkdocs_config = ["-v", "#{@config.data_dir}/mkdocs-patch.yml:/app/mkdocs-patch.yml"]
         docker_opts.concat docker_opt_mkdocs_config
-        Log.info { "Mkdocs: detected mkdocs-patch.yml file. Adding option to command line (#{docker_opt_mkdocs_config})" }
+        Log.info { "Docs: detected mkdocs-patch.yml file. Adding option to command line (#{docker_opt_mkdocs_config})" }
       else
-        Log.info { "Mkdocs: no mkdocs-patch.yml detected. Using default files" }
-        end
-
-      ## Detect slides
-      if Dir.exists?("#{@config.data_dir}/slides")
-        docker_opt_marp_port = ["-p", "5200:5200"]
-        docker_opts.concat docker_opt_marp_port 
-        Log.info { "Slides: detected slides directory. Adding option to command line (#{docker_opt_marp_port})" }
-      else
-        Log.info { "Slides: no slides directory detected." }
+        Log.info { "Docs: no mkdocs-patch.yml detected. Using default files" }
         end
 
       ## Detect docs
       if Dir.exists?("#{@config.data_dir}/docs")
-        docker_opt_marp_port = ["-p", "5100:5100"]
-        docker_opts.concat docker_opt_marp_port
-        Log.info { "Slides: detected docs directory. Adding option to command line (#{docker_opt_marp_port})" }
+        Log.info { "Docs: detected docs directory." }
+        mkdocs_port = _find_port(@config.port)
+        docker_opt_mkdocs_port = ["-p", "#{mkdocs_port}:5100"]
+        docker_opts.concat docker_opt_mkdocs_port
+        Log.notice { "Using port #{mkdocs_port} for docs" }
+        Log.info { "Docs: Adding option to command line (#{docker_opt_marp_port})" }
       else
-        Log.info { "Slides: no slides docs detected." }
+        Log.info { "Docs: no docs detected." }
+      end
+
+      ## Detect slides
+      if Dir.exists?("#{@config.data_dir}/slides")
+        Log.info { "Slides: detected slides directory." }
+        marp_port = _find_port(@config.port+100)
+        docker_opt_marp_port = ["-p", "#{marp_port}:5200"]
+        docker_opts.concat docker_opt_marp_port 
+        Log.info { "Slides: Adding option to command line (#{docker_opt_marp_port})" }
+        Log.notice { "Slides: Using port #{marp_port} for slides" }
+      else
+        Log.info { "Slides: no slides directory detected." }
         end
 
       docker_opts << @docker_image