diff --git a/src/class_diagram/generators/mermaid/class_diagram_generator.cc b/src/class_diagram/generators/mermaid/class_diagram_generator.cc
index 15c66af6..59b69050 100644
--- a/src/class_diagram/generators/mermaid/class_diagram_generator.cc
+++ b/src/class_diagram/generators/mermaid/class_diagram_generator.cc
@@ -33,6 +33,11 @@ generator::generator(diagram_config &config, diagram_model &model)
 {
 }
 
+void generator::generate_diagram_type(std::ostream &ostr) const
+{
+    ostr << "classDiagram\n";
+}
+
 void generator::generate_alias(
     const common::model::element &c, std::ostream &ostr) const
 {
@@ -696,8 +701,6 @@ void generator::generate_relationships(
 
 void generator::generate_diagram(std::ostream &ostr) const
 {
-    ostr << "classDiagram\n";
-
     generate_top_level_elements(ostr);
 
     generate_groups(ostr);
diff --git a/src/class_diagram/generators/mermaid/class_diagram_generator.h b/src/class_diagram/generators/mermaid/class_diagram_generator.h
index 4a8bd118..0ec125af 100644
--- a/src/class_diagram/generators/mermaid/class_diagram_generator.h
+++ b/src/class_diagram/generators/mermaid/class_diagram_generator.h
@@ -79,6 +79,13 @@ public:
      */
     void generate_diagram(std::ostream &ostr) const override;
 
+    /**
+     * @brief Generate the diagram type
+     *
+     * @param ostr Output stream
+     */
+    void generate_diagram_type(std::ostream &ostr) const override;
+
     /**
      * @brief In a nested diagram, generate the top level elements.
      *
diff --git a/src/common/generators/mermaid/generator.h b/src/common/generators/mermaid/generator.h
index 55776f67..6917b968 100644
--- a/src/common/generators/mermaid/generator.h
+++ b/src/common/generators/mermaid/generator.h
@@ -107,6 +107,16 @@ public:
     void generate_mermaid_directives(
         std::ostream &ostr, const std::vector<std::string> &directives) const;
 
+    /**
+     * @brief Generate the diagram type
+     *
+     * This method must be overriden for each diagram type (e.g. it renders
+     * a single line `classDiagram` for Mermaid class diagrams.
+     *
+     * @param ostr Output stream
+     */
+    virtual void generate_diagram_type(std::ostream &ostr) const = 0;
+
     /**
      * @brief Generate diagram notes
      *
@@ -228,13 +238,13 @@ void generator<C, D>::generate(std::ostream &ostr) const
 
     update_context();
 
-    // generate_mermaid_diagram_type(ostr, config);
+    generate_diagram_type(ostr);
 
-    generate_mermaid_directives(ostr, config.puml().before);
+    generate_mermaid_directives(ostr, config.mermaid().before);
 
     generate_diagram(ostr);
 
-    generate_mermaid_directives(ostr, config.puml().after);
+    generate_mermaid_directives(ostr, config.mermaid().after);
 
     generate_metadata(ostr);
 }
@@ -304,6 +314,61 @@ template <typename C, typename D>
 void generator<C, D>::generate_mermaid_directives(
     std::ostream &ostr, const std::vector<std::string> &directives) const
 {
+
+    const auto &config = generators::generator<C, D>::config();
+    const auto &model = generators::generator<C, D>::model();
+
+    using common::model::namespace_;
+
+    for (const auto &d : directives) {
+        try {
+            // Render the directive with template engine first
+            std::string directive{env().render(std::string_view{d}, context())};
+
+            // Now search for alias `@A()` directives in the text
+            // (this is deprecated)
+            std::tuple<std::string, size_t, size_t> alias_match;
+            while (util::find_element_alias(directive, alias_match)) {
+                const auto full_name =
+                    config.using_namespace() | std::get<0>(alias_match);
+                auto element_opt = model.get(full_name.to_string());
+
+                if (element_opt)
+                    directive.replace(std::get<1>(alias_match),
+                        std::get<2>(alias_match), element_opt.value().alias());
+                else {
+                    LOG_ERROR("Cannot find clang-uml alias for element {}",
+                        full_name.to_string());
+                    directive.replace(std::get<1>(alias_match),
+                        std::get<2>(alias_match), "UNKNOWN_ALIAS");
+                }
+            }
+
+            ostr << indent(1) << directive << '\n';
+        }
+        catch (const clanguml::error::uml_alias_missing &e) {
+            LOG_ERROR(
+                "Failed to render MermaidJS directive due to unresolvable "
+                "alias: {}",
+                e.what());
+        }
+        catch (const inja::json::parse_error &e) {
+            LOG_ERROR("Failed to parse Jinja template: {}", d);
+        }
+        catch (const inja::json::exception &e) {
+            LOG_ERROR("Failed to render MermaidJS directive: \n{}\n due to: {}",
+                d, e.what());
+        }
+        catch (const std::regex_error &e) {
+            LOG_ERROR("Failed to render MermaidJS directive: \n{}\n due to "
+                      "std::regex_error: {}",
+                d, e.what());
+        }
+        catch (const std::exception &e) {
+            LOG_ERROR("Failed to render PlantUML directive: \n{}\n due to: {}",
+                d, e.what());
+        }
+    }
 }
 
 template <typename C, typename D>
diff --git a/src/config/yaml_decoders.cc b/src/config/yaml_decoders.cc
index 1c0a9f45..c281f02b 100644
--- a/src/config/yaml_decoders.cc
+++ b/src/config/yaml_decoders.cc
@@ -42,6 +42,7 @@ using clanguml::config::include_diagram;
 using clanguml::config::layout_hint;
 using clanguml::config::location_t;
 using clanguml::config::member_order_t;
+using clanguml::config::mermaid;
 using clanguml::config::method_arguments;
 using clanguml::config::method_type;
 using clanguml::config::package_diagram;
@@ -389,6 +390,18 @@ template <> struct convert<plantuml> {
     }
 };
 
+template <> struct convert<mermaid> {
+    static bool decode(const Node &node, mermaid &rhs)
+    {
+        if (node["before"])
+            rhs.before = node["before"].as<decltype(rhs.before)>();
+
+        if (node["after"])
+            rhs.after = node["after"].as<decltype(rhs.after)>();
+        return true;
+    }
+};
+
 template <> struct convert<string_or_regex> {
     static bool decode(const Node &node, string_or_regex &rhs)
     {
@@ -531,6 +544,7 @@ template <typename T> bool decode_diagram(const Node &node, T &rhs)
     get_option(node, rhs.include);
     get_option(node, rhs.exclude);
     get_option(node, rhs.puml);
+    get_option(node, rhs.mermaid);
     get_option(node, rhs.git);
     get_option(node, rhs.generate_links);
     get_option(node, rhs.type_aliases);
@@ -762,6 +776,7 @@ template <> struct convert<config> {
         get_option(node, rhs.remove_compile_flags);
         get_option(node, rhs.include_relations_also_as_members);
         get_option(node, rhs.puml);
+        get_option(node, rhs.mermaid);
         get_option(node, rhs.generate_method_arguments);
         get_option(node, rhs.generate_packages);
         get_option(node, rhs.package_type);
diff --git a/src/include_diagram/generators/mermaid/include_diagram_generator.cc b/src/include_diagram/generators/mermaid/include_diagram_generator.cc
index 4c06e1ce..48cf3472 100644
--- a/src/include_diagram/generators/mermaid/include_diagram_generator.cc
+++ b/src/include_diagram/generators/mermaid/include_diagram_generator.cc
@@ -29,6 +29,11 @@ generator::generator(diagram_config &config, diagram_model &model)
 {
 }
 
+void generator::generate_diagram_type(std::ostream &ostr) const
+{
+    ostr << "flowchart\n";
+}
+
 void generator::generate_relationships(
     const source_file &f, std::ostream &ostr) const
 {
@@ -114,8 +119,6 @@ void generator::generate_notes(
 
 void generator::generate_diagram(std::ostream &ostr) const
 {
-    ostr << "flowchart\n";
-
     // Generate files and folders
     util::for_each(model(), [this, &ostr](const auto &f) {
         generate(dynamic_cast<source_file &>(*f), ostr);
diff --git a/src/include_diagram/generators/mermaid/include_diagram_generator.h b/src/include_diagram/generators/mermaid/include_diagram_generator.h
index 12afe076..4efaf94e 100644
--- a/src/include_diagram/generators/mermaid/include_diagram_generator.h
+++ b/src/include_diagram/generators/mermaid/include_diagram_generator.h
@@ -64,6 +64,13 @@ public:
      */
     void generate_diagram(std::ostream &ostr) const override;
 
+    /**
+     * @brief Generate the diagram type
+     *
+     * @param ostr Output stream
+     */
+    void generate_diagram_type(std::ostream &ostr) const override;
+
     /**
      * @brief Generate relationships originating from source_file `f`
      *
diff --git a/src/package_diagram/generators/mermaid/package_diagram_generator.cc b/src/package_diagram/generators/mermaid/package_diagram_generator.cc
index 8843ce64..1b68d131 100644
--- a/src/package_diagram/generators/mermaid/package_diagram_generator.cc
+++ b/src/package_diagram/generators/mermaid/package_diagram_generator.cc
@@ -30,6 +30,11 @@ generator::generator(diagram_config &config, diagram_model &model)
 {
 }
 
+void generator::generate_diagram_type(std::ostream &ostr) const
+{
+    ostr << "flowchart\n";
+}
+
 void generator::generate_relationships(
     const package &p, std::ostream &ostr) const
 {
@@ -144,8 +149,6 @@ void generator::generate_notes(
 
 void generator::generate_diagram(std::ostream &ostr) const
 {
-    ostr << "flowchart\n";
-
     for (const auto &p : model()) {
         auto &pkg = dynamic_cast<package &>(*p);
         if (model().should_include(pkg)) {
diff --git a/src/package_diagram/generators/mermaid/package_diagram_generator.h b/src/package_diagram/generators/mermaid/package_diagram_generator.h
index c7d07e68..e17ca55c 100644
--- a/src/package_diagram/generators/mermaid/package_diagram_generator.h
+++ b/src/package_diagram/generators/mermaid/package_diagram_generator.h
@@ -66,6 +66,13 @@ public:
      */
     void generate_diagram(std::ostream &ostr) const override;
 
+    /**
+     * @brief Generate the diagram type
+     *
+     * @param ostr Output stream
+     */
+    void generate_diagram_type(std::ostream &ostr) const override;
+
     /**
      * @brief Generate relationships originating from package `p`
      *
diff --git a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
index 229b3b54..65870510 100644
--- a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
+++ b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
@@ -48,6 +48,11 @@ generator::generator(
 {
 }
 
+void generator::generate_diagram_type(std::ostream &ostr) const
+{
+    ostr << "sequenceDiagram\n";
+}
+
 void generator::generate_call(const message &m, std::ostream &ostr) const
 {
     const auto &from = model().get_participant<model::participant>(m.from());
@@ -389,8 +394,6 @@ void generator::generate_diagram(std::ostream &ostr) const
 {
     model().print();
 
-    ostr << "sequenceDiagram\n";
-
     if (config().participants_order.has_value) {
         for (const auto &p : config().participants_order()) {
             LOG_DBG("Pregenerating participant {}", p);
diff --git a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.h b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.h
index 823f729f..c6bbd33d 100644
--- a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.h
+++ b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.h
@@ -60,6 +60,13 @@ public:
      */
     void generate_diagram(std::ostream &ostr) const override;
 
+    /**
+     * @brief Generate the diagram type
+     *
+     * @param ostr Output stream
+     */
+    void generate_diagram_type(std::ostream &ostr) const override;
+
     /**
      * @brief Generate sequence diagram message.
      *
diff --git a/tests/t20006/test_case.h b/tests/t20006/test_case.h
index 625341ae..d2913f07 100644
--- a/tests/t20006/test_case.h
+++ b/tests/t20006/test_case.h
@@ -96,4 +96,10 @@ TEST_CASE("t20006", "[test-case][sequence]")
 
         save_json(config.output_directory(), diagram->name + ".json", j);
     }
+
+    {
+        auto mmd = generate_sequence_mermaid(diagram, *model);
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+    }
 }
\ No newline at end of file
diff --git a/tests/t20012/test_case.h b/tests/t20012/test_case.h
index fe1b70c6..2b9f099f 100644
--- a/tests/t20012/test_case.h
+++ b/tests/t20012/test_case.h
@@ -121,4 +121,10 @@ TEST_CASE("t20012", "[test-case][sequence]")
 
         save_json(config.output_directory(), diagram->name + ".json", j);
     }
+
+    {
+        auto mmd = generate_sequence_mermaid(diagram, *model);
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+    }
 }
diff --git a/tests/t90000/.clang-uml b/tests/t90000/.clang-uml
index e09671a3..7f12a85b 100644
--- a/tests/t90000/.clang-uml
+++ b/tests/t90000/.clang-uml
@@ -18,3 +18,15 @@ diagrams:
         - 'class "Boo" as C_002'
         - 'class C_002 {'
         - '}'
+    mermaid:
+      before:
+        - 'class C_001["Foo"]'
+        - 'class C_001 {'
+        - ' +int value'
+        - '}'
+        - 'C_001 <|-- ArrayList'
+        - 'note for C_001 "This is a very important class."'
+        - 'note "This is a\nfloating note"'
+        - 'class C_002["Boo"]'
+        - 'class C_002 {'
+        - '}'
diff --git a/tests/t90000/test_case.h b/tests/t90000/test_case.h
index dda3d671..84d50e58 100644
--- a/tests/t90000/test_case.h
+++ b/tests/t90000/test_case.h
@@ -26,14 +26,30 @@ TEST_CASE("t90000", "[test-case][config]")
 
     REQUIRE(model->name() == "t90000_class");
 
-    auto puml = generate_class_puml(diagram, *model);
-    AliasMatcher _A(puml);
+    {
+        auto puml = generate_class_puml(diagram, *model);
+        AliasMatcher _A(puml);
 
-    REQUIRE_THAT(puml, StartsWith("@startuml"));
-    REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+        REQUIRE_THAT(puml, StartsWith("@startuml"));
+        REQUIRE_THAT(puml, EndsWith("@enduml\n"));
 
-    REQUIRE_THAT(puml, IsClass(_A("Foo")));
-    REQUIRE_THAT(puml, IsClass(_A("Boo")));
+        REQUIRE_THAT(puml, IsClass(_A("Foo")));
+        REQUIRE_THAT(puml, IsClass(_A("Boo")));
 
-    save_puml(config.output_directory(), diagram->name + ".puml", puml);
+        save_puml(config.output_directory(), diagram->name + ".puml", puml);
+    }
+
+    {
+        auto j = generate_class_json(diagram, *model);
+
+        using namespace json;
+
+        save_json(config.output_directory(), diagram->name + ".json", j);
+    }
+
+    {
+        auto mmd = generate_class_mermaid(diagram, *model);
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+    }
 }
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index c5714ad7..b2e6222a 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -282,7 +282,6 @@ void save_puml(const std::string &path, const std::string &filename,
     const std::string &puml)
 {
     std::filesystem::path p{path};
-    p /= "puml";
     p /= filename;
     save_diagram(p, puml);
 }
@@ -291,7 +290,6 @@ void save_json(const std::string &path, const std::string &filename,
     const nlohmann::json &j)
 {
     std::filesystem::path p{path};
-    p /= "json";
     p /= filename;
     save_diagram(p, j);
 }
@@ -300,7 +298,6 @@ void save_mermaid(const std::string &path, const std::string &filename,
     const std::string &mmd)
 {
     std::filesystem::path p{path};
-    p /= "mermaid";
     p /= filename;
     save_diagram(p, mmd);
 }