diff --git a/README.md b/README.md
index 0dd6635..43c9359 100644
--- a/README.md
+++ b/README.md
@@ -36,11 +36,12 @@ Options:
   -o, --output PATH        [required]
   -t, --template-dir PATH
   -m, --model-file         Specify generated model file path + name, if not default to models.py
+  -r, --generate-routers   Generate modular api with multiple routers using RouterAPI (for bigger applications).
+  --specify-tags           Use along with --generate-routers to generate specific routers from given list of tags.
   -c, --custom-visitors    PATH - A custom visitor that adds variables to the template.
   --install-completion     Install completion for the current shell.
   --show-completion        Show completion for the current shell, to copy it
                            or customize the installation.
-
   --help                   Show this message and exit.
 ```
 
@@ -313,6 +314,79 @@ def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operati
 
 ```
 
+### modular template
+`modular_template/main.jinja2`:
+```jinja
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import {{ routers | join(", ") }}
+
+app = FastAPI(
+    {% if info %}
+    {% for key,value in info.items() %}
+    {% set info_value= value.__repr__() %}
+    {{ key }} = {{info_value}},
+    {% endfor %}
+    {% endif %}
+    )
+
+{% for router in routers -%}
+app.include_router({{router}}.router)
+{% endfor -%}
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
+```
+
+`modular_template/routers.jinja2`:
+```jinja
+from __future__ import annotations
+
+from fastapi import APIRouter
+from fastapi import FastAPI
+
+from ..dependencies import *
+
+router = APIRouter(
+    tags=['{{tag}}']
+    )
+
+{% for operation in operations %}
+{% if operation.tags[0] == tag %}
+@router.{{operation.type}}('{{operation.snake_case_path}}', response_model={{operation.response}}
+    {% if operation.additional_responses %}
+        , responses={
+            {% for status_code, models in operation.additional_responses.items() %}
+                '{{ status_code }}': {
+                {% for key, model in models.items() %}
+                    '{{ key }}': {{ model }}{% if not loop.last %},{% endif %}
+                {% endfor %}
+                }{% if not loop.last %},{% endif %}
+            {% endfor %}
+        }
+    {% endif %}
+    {% if operation.tags%}
+    , tags={{operation.tags}}
+    {% endif %})
+def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operation.return_type}}:
+    {%- if operation.summary %}
+    """
+    {{ operation.summary }}
+    """
+    {%- endif %}
+    pass
+{% endif %}
+{% endfor %}
+```
+
+`modular_template/dependencies.jinja2`:
+```jinja
+{{imports}}
+```
+
 ## Custom Visitors
 
 Custom visitors allow you to pass custom variables to your custom templates.
@@ -346,6 +420,424 @@ def custom_visitor(parser: OpenAPIParser, model_path: Path) -> Dict[str, object]
 visit: Visitor = custom_visitor
 ```
 
+### Multiple Files using APIRouter (For Bigger Applications)
+
+```
+├── app                      # "app" is a Root directory      
+│   ├── main.py              # "main" module
+│   ├── models.py            # "models" of the application
+│   ├── dependencies.py      # "dependencies" module, e.g. import app.dependencies
+│   └── routers              # "routers" is a "app subpackage"
+│       ├── fat_cats.py      # "fat_cats" submodule, e.g. import app.routers.fat_cats
+│       ├── slim_dogs.py     # "slim_dogs" submodule, e.g. import app.routers.slim_dogs
+│       └── wild_boars.py    # "wild_boars" submodule, e.g. import app.routers.wild_boars
+```
+
+See [documentation](https://fastapi.tiangolo.com/tutorial/bigger-applications/) of APIRouter OpenAPI for more details.
+
+**_Generate main aside with all of its routers_**:
+```bash
+$ fastapi-codegen --input swagger.yaml --output app --generate-routers
+```
+
+**_Regenerate specific routers_**:
+```bash
+$ fastapi-codegen --input swagger.yaml --output app --generate-routers --specify-tags "Wild Boars, Fat Cats"
+```
+
+
+<details>
+<summary>swagger.yaml</summary>
+<pre>
+<code>
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: /
+  - url: http://petstore.swagger.io/v1
+  - url: http://localhost:8080/
+paths:
+  /boars:
+    get:
+      summary: List All Wild Boars
+      operationId: listWildBoars
+      tags:
+        - Wild Boars
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of wild boars
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/WildBoars"
+    post:
+      summary: Create a Wild Boar
+      operationId: createWildBoars
+      tags:
+        - Wild Boars
+      responses:
+        '201':
+          description: Null response
+  /boars/{boarId}:
+    get:
+      summary: Info For a Specific Boar
+      operationId: showBoarById
+      tags:
+        - Wild Boars
+      parameters:
+        - name: boarId
+          in: path
+          required: true
+          description: The id of the boar to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /cats:
+    get:
+      summary: List All Fat Cats
+      operationId: listFatCats
+      tags:
+        - Fat Cats
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of fat cats
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FatCats"
+    post:
+      summary: Create a Fat Cat
+      operationId: createFatCats
+      tags:
+        - Fat Cats
+      responses:
+        '201':
+          description: Null response
+  /cats/{catId}:
+    get:
+      summary: Info For a Specific Cat
+      operationId: showCatById
+      tags:
+        - Fat Cats
+      parameters:
+        - name: catId
+          in: path
+          required: true
+          description: The id of the cat to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /dogs:
+    get:
+      summary: List All Slim Dogs
+      operationId: listSlimDogs
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of slim dogs
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/SlimDogs"
+    post:
+      summary: Create a Slim Dog
+      operationId: createSlimDogs
+      tags:
+        - Slim Dogs
+      responses:
+        '201':
+          description: Null response
+  /dogs/{dogId}:
+    get:
+      summary: Info For a Specific Dog
+      operationId: showDogById
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: dogId
+          in: path
+          required: true
+          description: The id of the dog to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+        tag:
+          type: string
+    FatCats:
+      type: array
+      description: list of fat cats
+      items:
+        $ref: "#/components/schemas/Pet"
+    SlimDogs:
+      type: array
+      description: list of slim dogs
+      items:
+        $ref: "#/components/schemas/Pet"
+    WildBoars:
+      type: array
+      description: list of wild boars
+      items:
+        $ref: "#/components/schemas/Pet"
+</code>
+</pre>
+</details>
+
+`app/main.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import fat_cats, slim_dogs, wild_boars
+
+app = FastAPI(
+    version='1.0.0',
+    title='Swagger Petstore',
+    license={'name': 'MIT'},
+    servers=[
+        {'url': '/'},
+        {'url': 'http://petstore.swagger.io/v1'},
+        {'url': 'http://localhost:8080/'},
+    ],
+)
+
+app.include_router(fat_cats.router)
+app.include_router(slim_dogs.router)
+app.include_router(wild_boars.router)
+
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
+```
+
+`app/models.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+
+class Pet(BaseModel):
+    id: int
+    name: str
+    tag: Optional[str] = None
+
+
+class FatCats(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of fat cats')
+
+
+class SlimDogs(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of slim dogs')
+
+
+class WildBoars(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of wild boars')
+```
+
+`app/routers/fat_cats.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Fat Cats'])
+
+
+@router.get('/cats', response_model=FatCats, tags=['Fat Cats'])
+def list_fat_cats(limit: Optional[int] = None) -> FatCats:
+    """
+    List All Fat Cats
+    """
+    pass
+
+
+@router.post('/cats', response_model=None, tags=['Fat Cats'])
+def create_fat_cats() -> None:
+    """
+    Create a Fat Cat
+    """
+    pass
+
+
+@router.get('/cats/{cat_id}', response_model=Pet, tags=['Fat Cats'])
+def show_cat_by_id(cat_id: str = Path(..., alias='catId')) -> Pet:
+    """
+    Info For a Specific Cat
+    """
+    pass
+```
+
+`app/routers/slim_dogs.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Slim Dogs'])
+
+
+@router.get('/dogs', response_model=SlimDogs, tags=['Slim Dogs'])
+def list_slim_dogs(limit: Optional[int] = None) -> SlimDogs:
+    """
+    List All Slim Dogs
+    """
+    pass
+
+
+@router.post('/dogs', response_model=None, tags=['Slim Dogs'])
+def create_slim_dogs() -> None:
+    """
+    Create a Slim Dog
+    """
+    pass
+
+
+@router.get('/dogs/{dog_id}', response_model=Pet, tags=['Slim Dogs'])
+def show_dog_by_id(dog_id: str = Path(..., alias='dogId')) -> Pet:
+    """
+    Info For a Specific Dog
+    """
+    pass
+```
+
+`app/routers/wild_boars.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Wild Boars'])
+
+
+@router.get('/boars', response_model=WildBoars, tags=['Wild Boars'])
+def list_wild_boars(limit: Optional[int] = None) -> WildBoars:
+    """
+    List All Wild Boars
+    """
+    pass
+
+
+@router.post('/boars', response_model=None, tags=['Wild Boars'])
+def create_wild_boars() -> None:
+    """
+    Create a Wild Boar
+    """
+    pass
+
+
+@router.get('/boars/{boar_id}', response_model=Pet, tags=['Wild Boars'])
+def show_boar_by_id(boar_id: str = Path(..., alias='boarId')) -> Pet:
+    """
+    Info For a Specific Boar
+    """
+    pass
+```
+
+`app/dependencies.py`:
+
+```python
+# generated by fastapi-codegen:
+#   filename:  swagger.yaml
+#   timestamp: 2023-04-04T12:06:16+00:00
+
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import Path
+
+from .models import FatCats, Pet, SlimDogs, WildBoars
+```
 ## PyPi 
 
 [https://pypi.org/project/fastapi-code-generator](https://pypi.org/project/fastapi-code-generator)
diff --git a/fastapi_code_generator/__main__.py b/fastapi_code_generator/__main__.py
index 25bb43e..9f214e8 100644
--- a/fastapi_code_generator/__main__.py
+++ b/fastapi_code_generator/__main__.py
@@ -1,3 +1,4 @@
+import re
 from datetime import datetime, timezone
 from importlib.util import module_from_spec, spec_from_file_location
 from pathlib import Path
@@ -16,6 +17,12 @@
 
 app = typer.Typer()
 
+all_tags = []
+
+TITLE_PATTERN = re.compile(r'(?<!^)(?<![A-Z ])(?=[A-Z])| ')
+
+BUILTIN_MODULAR_TEMPLATE_DIR = Path(__file__).parent / "modular_template"
+
 BUILTIN_TEMPLATE_DIR = Path(__file__).parent / "template"
 
 BUILTIN_VISITOR_DIR = Path(__file__).parent / "visitors"
@@ -43,6 +50,8 @@ def main(
     enum_field_as_literal: Optional[LiteralType] = typer.Option(
         None, "--enum-field-as-literal"
     ),
+    generate_routers: bool = typer.Option(False, "--generate-routers", "-r"),
+    specify_tags: Optional[str] = typer.Option(None, "--specify-tags"),
     custom_visitors: Optional[List[Path]] = typer.Option(
         None, "--custom-visitor", "-c"
     ),
@@ -54,6 +63,7 @@ def main(
         model_path = Path(model_file).with_suffix('.py')
     else:
         model_path = MODEL_PATH
+
     if enum_field_as_literal:
         return generate_code(
             input_name,
@@ -63,6 +73,8 @@ def main(
             model_path,
             enum_field_as_literal,
             disable_timestamp=disable_timestamp,
+            generate_routers=generate_routers,
+            specify_tags=specify_tags,
         )
     return generate_code(
         input_name,
@@ -72,6 +84,8 @@ def main(
         model_path,
         custom_visitors=custom_visitors,
         disable_timestamp=disable_timestamp,
+        generate_routers=generate_routers,
+        specify_tags=specify_tags,
     )
 
 
@@ -94,11 +108,16 @@ def generate_code(
     enum_field_as_literal: Optional[str] = None,
     custom_visitors: Optional[List[Path]] = [],
     disable_timestamp: bool = False,
+    generate_routers: Optional[bool] = None,
+    specify_tags: Optional[str] = None,
 ) -> None:
     if not model_path:
         model_path = MODEL_PATH
     if not output_dir.exists():
         output_dir.mkdir(parents=True)
+    if generate_routers:
+        template_dir = BUILTIN_MODULAR_TEMPLATE_DIR
+        Path(output_dir / "routers").mkdir(parents=True, exist_ok=True)
     if not template_dir:
         template_dir = BUILTIN_TEMPLATE_DIR
     if enum_field_as_literal:
@@ -143,12 +162,52 @@ def generate_code(
         visitor_result = visitor(parser, model_path)
         template_vars = {**template_vars, **visitor_result}
 
+    if generate_routers:
+        operations: Any = template_vars.get("operations", [])
+        for operation in operations:
+            if hasattr(operation, "tags"):
+                for tag in operation.tags:
+                    all_tags.append(tag)
+    # Convert from Tag Names to router_names
+    sorted_tags = sorted(set(all_tags))
+    routers = sorted(
+        [re.sub(TITLE_PATTERN, '_', tag.strip()).lower() for tag in sorted_tags]
+    )
+    template_vars = {**template_vars, "routers": routers, "tags": sorted_tags}
+
     for target in template_dir.rglob("*"):
         relative_path = target.relative_to(template_dir)
         template = environment.get_template(str(relative_path))
         result = template.render(template_vars)
         results[relative_path] = code_formatter.format_code(result)
 
+    if generate_routers:
+        tags = sorted_tags
+        results.pop(Path("routers.jinja2"))
+        if specify_tags:
+            if Path(output_dir.joinpath("main.py")).exists():
+                with open(Path(output_dir.joinpath("main.py")), 'r') as file:
+                    content = file.read()
+                    if "app.include_router" in content:
+                        tags = sorted(
+                            set(tag.strip() for tag in str(specify_tags).split(","))
+                        )
+
+        for target in BUILTIN_MODULAR_TEMPLATE_DIR.rglob("routers.*"):
+            relative_path = target.relative_to(template_dir)
+            for router, tag in zip(routers, sorted_tags):
+                if (
+                    not Path(output_dir.joinpath("routers", router))
+                    .with_suffix(".py")
+                    .exists()
+                    or tag in tags
+                ):
+                    template_vars["tag"] = tag.strip()
+                    template = environment.get_template(str(relative_path))
+                    result = template.render(template_vars)
+                    router_path = Path("routers", router).with_suffix(".jinja2")
+                    results[router_path] = code_formatter.format_code(result)
+
     timestamp = datetime.now(timezone.utc).replace(microsecond=0).isoformat()
     header = f"""\
 # generated by fastapi-codegen:
diff --git a/fastapi_code_generator/modular_template/dependencies.jinja2 b/fastapi_code_generator/modular_template/dependencies.jinja2
new file mode 100644
index 0000000..ef3149f
--- /dev/null
+++ b/fastapi_code_generator/modular_template/dependencies.jinja2
@@ -0,0 +1 @@
+{{imports}}
\ No newline at end of file
diff --git a/fastapi_code_generator/modular_template/main.jinja2 b/fastapi_code_generator/modular_template/main.jinja2
new file mode 100644
index 0000000..8d6a33d
--- /dev/null
+++ b/fastapi_code_generator/modular_template/main.jinja2
@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import {{ routers | join(", ") }}
+
+app = FastAPI(
+    {% if info %}
+    {% for key,value in info.items() %}
+    {% set info_value= value.__repr__() %}
+    {{ key }} = {{info_value}},
+    {% endfor %}
+    {% endif %}
+    )
+
+{% for router in routers -%}
+app.include_router({{router}}.router)
+{% endfor -%}
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
diff --git a/fastapi_code_generator/modular_template/routers.jinja2 b/fastapi_code_generator/modular_template/routers.jinja2
new file mode 100644
index 0000000..0cec624
--- /dev/null
+++ b/fastapi_code_generator/modular_template/routers.jinja2
@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(
+    tags=['{{tag}}']
+    )
+
+{% for operation in operations %}
+{% if operation.tags[0] == tag %}
+@router.{{operation.type}}('{{operation.snake_case_path}}', response_model={{operation.response}}
+    {% if operation.additional_responses %}
+        , responses={
+            {% for status_code, models in operation.additional_responses.items() %}
+                '{{ status_code }}': {
+                {% for key, model in models.items() %}
+                    '{{ key }}': {{ model }}{% if not loop.last %},{% endif %}
+                {% endfor %}
+                }{% if not loop.last %},{% endif %}
+            {% endfor %}
+        }
+    {% endif %}
+    {% if operation.tags%}
+    , tags={{operation.tags}}
+    {% endif %})
+def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operation.return_type}}:
+    {%- if operation.summary %}
+    """
+    {{ operation.summary }}
+    """
+    {%- endif %}
+    pass
+{% endif %}
+{% endfor %}
\ No newline at end of file
diff --git a/swagger.yaml b/swagger.yaml
new file mode 100644
index 0000000..8b12cb7
--- /dev/null
+++ b/swagger.yaml
@@ -0,0 +1,184 @@
+
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: /
+  - url: http://petstore.swagger.io/v1
+  - url: http://localhost:8080/
+paths:
+  /boars:
+    get:
+      summary: List All Wild Boars
+      operationId: listWildBoars
+      tags:
+        - Wild Boars
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of wild boars
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/WildBoars"
+    post:
+      summary: Create a Wild Boar
+      operationId: createWildBoars
+      tags:
+        - Wild Boars
+      responses:
+        '201':
+          description: Null response
+  /boars/{boarId}:
+    get:
+      summary: Info For a Specific Boar
+      operationId: showBoarById
+      tags:
+        - Wild Boars
+      parameters:
+        - name: boarId
+          in: path
+          required: true
+          description: The id of the boar to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /cats:
+    get:
+      summary: List All Fat Cats
+      operationId: listFatCats
+      tags:
+        - Fat Cats
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of fat cats
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FatCats"
+    post:
+      summary: Create a Fat Cat
+      operationId: createFatCats
+      tags:
+        - Fat Cats
+      responses:
+        '201':
+          description: Null response
+  /cats/{catId}:
+    get:
+      summary: Info For a Specific Cat
+      operationId: showCatById
+      tags:
+        - Fat Cats
+      parameters:
+        - name: catId
+          in: path
+          required: true
+          description: The id of the cat to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /dogs:
+    get:
+      summary: List All Slim Dogs
+      operationId: listSlimDogs
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of slim dogs
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/SlimDogs"
+    post:
+      summary: Create a Slim Dog
+      operationId: createSlimDogs
+      tags:
+        - Slim Dogs
+      responses:
+        '201':
+          description: Null response
+  /dogs/{dogId}:
+    get:
+      summary: Info For a Specific Dog
+      operationId: showDogById
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: dogId
+          in: path
+          required: true
+          description: The id of the dog to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+        tag:
+          type: string
+    FatCats:
+      type: array
+      description: list of fat cats
+      items:
+        $ref: "#/components/schemas/Pet"
+    SlimDogs:
+      type: array
+      description: list of slim dogs
+      items:
+        $ref: "#/components/schemas/Pet"
+    WildBoars:
+      type: array
+      description: list of wild boars
+      items:
+        $ref: "#/components/schemas/Pet"
\ No newline at end of file
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/dependencies.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/dependencies.py
new file mode 100644
index 0000000..ede6084
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/dependencies.py
@@ -0,0 +1,11 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import Path
+
+from .models import FatCats, Pet, SlimDogs, WildBoars
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/main.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/main.py
new file mode 100644
index 0000000..b6de4f4
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/main.py
@@ -0,0 +1,29 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import fat_cats, slim_dogs, wild_boars
+
+app = FastAPI(
+    version='1.0.0',
+    title='Swagger Petstore',
+    license={'name': 'MIT'},
+    servers=[
+        {'url': '/'},
+        {'url': 'http://petstore.swagger.io/v1'},
+        {'url': 'http://localhost:8080/'},
+    ],
+)
+
+app.include_router(fat_cats.router)
+app.include_router(slim_dogs.router)
+app.include_router(wild_boars.router)
+
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/models.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/models.py
new file mode 100644
index 0000000..ceb4515
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/models.py
@@ -0,0 +1,27 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+
+class Pet(BaseModel):
+    id: int
+    name: str
+    tag: Optional[str] = None
+
+
+class FatCats(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of fat cats')
+
+
+class SlimDogs(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of slim dogs')
+
+
+class WildBoars(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of wild boars')
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/fat_cats.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/fat_cats.py
new file mode 100644
index 0000000..77a7da4
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/fat_cats.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Fat Cats'])
+
+
+@router.get('/cats', response_model=FatCats, tags=['Fat Cats'])
+def list_fat_cats(limit: Optional[int] = None) -> FatCats:
+    """
+    List All Fat Cats
+    """
+    pass
+
+
+@router.post('/cats', response_model=None, tags=['Fat Cats'])
+def create_fat_cats() -> None:
+    """
+    Create a Fat Cat
+    """
+    pass
+
+
+@router.get('/cats/{cat_id}', response_model=Pet, tags=['Fat Cats'])
+def show_cat_by_id(cat_id: str = Path(..., alias='catId')) -> Pet:
+    """
+    Info For a Specific Cat
+    """
+    pass
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/slim_dogs.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/slim_dogs.py
new file mode 100644
index 0000000..170237f
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/slim_dogs.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Slim Dogs'])
+
+
+@router.get('/dogs', response_model=SlimDogs, tags=['Slim Dogs'])
+def list_slim_dogs(limit: Optional[int] = None) -> SlimDogs:
+    """
+    List All Slim Dogs
+    """
+    return SlimDogs.parse_obj([{"id": "9", "name": "Pluto"}])
+
+
+@router.post('/dogs', response_model=None, tags=['Slim Dogs'])
+def create_slim_dogs() -> None:
+    """
+    Create a Slim Dog
+    """
+    return None
+
+
+@router.get('/dogs/{dog_id}', response_model=Pet, tags=['Slim Dogs'])
+def show_dog_by_id(dog_id: str = Path(..., alias='dogId')) -> Pet:
+    """
+    Info For a Specific Dog
+    """
+    return Pet.parse_obj({"id": dog_id, "name": "Pluto"})
\ No newline at end of file
diff --git a/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/wild_boars.py b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/wild_boars.py
new file mode 100644
index 0000000..b0a849e
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/expected/using_routers_example/routers/wild_boars.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Wild Boars'])
+
+
+@router.get('/boars', response_model=WildBoars, tags=['Wild Boars'])
+def list_wild_boars(limit: Optional[int] = None) -> WildBoars:
+    """
+    List All Wild Boars
+    """
+    pass
+
+
+@router.post('/boars', response_model=None, tags=['Wild Boars'])
+def create_wild_boars() -> None:
+    """
+    Create a Wild Boar
+    """
+    pass
+
+
+@router.get('/boars/{boar_id}', response_model=Pet, tags=['Wild Boars'])
+def show_boar_by_id(boar_id: str = Path(..., alias='boarId')) -> Pet:
+    """
+    Info For a Specific Boar
+    """
+    pass
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/dependencies.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/dependencies.py
new file mode 100644
index 0000000..ede6084
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/dependencies.py
@@ -0,0 +1,11 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import Path
+
+from .models import FatCats, Pet, SlimDogs, WildBoars
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/main.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/main.py
new file mode 100644
index 0000000..b6de4f4
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/main.py
@@ -0,0 +1,29 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import fat_cats, slim_dogs, wild_boars
+
+app = FastAPI(
+    version='1.0.0',
+    title='Swagger Petstore',
+    license={'name': 'MIT'},
+    servers=[
+        {'url': '/'},
+        {'url': 'http://petstore.swagger.io/v1'},
+        {'url': 'http://localhost:8080/'},
+    ],
+)
+
+app.include_router(fat_cats.router)
+app.include_router(slim_dogs.router)
+app.include_router(wild_boars.router)
+
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/models.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/models.py
new file mode 100644
index 0000000..ceb4515
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/models.py
@@ -0,0 +1,27 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+
+class Pet(BaseModel):
+    id: int
+    name: str
+    tag: Optional[str] = None
+
+
+class FatCats(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of fat cats')
+
+
+class SlimDogs(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of slim dogs')
+
+
+class WildBoars(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of wild boars')
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/fat_cats.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/fat_cats.py
new file mode 100644
index 0000000..77a7da4
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/fat_cats.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Fat Cats'])
+
+
+@router.get('/cats', response_model=FatCats, tags=['Fat Cats'])
+def list_fat_cats(limit: Optional[int] = None) -> FatCats:
+    """
+    List All Fat Cats
+    """
+    pass
+
+
+@router.post('/cats', response_model=None, tags=['Fat Cats'])
+def create_fat_cats() -> None:
+    """
+    Create a Fat Cat
+    """
+    pass
+
+
+@router.get('/cats/{cat_id}', response_model=Pet, tags=['Fat Cats'])
+def show_cat_by_id(cat_id: str = Path(..., alias='catId')) -> Pet:
+    """
+    Info For a Specific Cat
+    """
+    pass
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/slim_dogs.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/slim_dogs.py
new file mode 100644
index 0000000..170237f
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/slim_dogs.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Slim Dogs'])
+
+
+@router.get('/dogs', response_model=SlimDogs, tags=['Slim Dogs'])
+def list_slim_dogs(limit: Optional[int] = None) -> SlimDogs:
+    """
+    List All Slim Dogs
+    """
+    return SlimDogs.parse_obj([{"id": "9", "name": "Pluto"}])
+
+
+@router.post('/dogs', response_model=None, tags=['Slim Dogs'])
+def create_slim_dogs() -> None:
+    """
+    Create a Slim Dog
+    """
+    return None
+
+
+@router.get('/dogs/{dog_id}', response_model=Pet, tags=['Slim Dogs'])
+def show_dog_by_id(dog_id: str = Path(..., alias='dogId')) -> Pet:
+    """
+    Info For a Specific Dog
+    """
+    return Pet.parse_obj({"id": dog_id, "name": "Pluto"})
\ No newline at end of file
diff --git a/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/wild_boars.py b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/wild_boars.py
new file mode 100644
index 0000000..b0a849e
--- /dev/null
+++ b/tests/data/expected/openapi/modify_specific_routers/modified/using_routers_example/routers/wild_boars.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Wild Boars'])
+
+
+@router.get('/boars', response_model=WildBoars, tags=['Wild Boars'])
+def list_wild_boars(limit: Optional[int] = None) -> WildBoars:
+    """
+    List All Wild Boars
+    """
+    pass
+
+
+@router.post('/boars', response_model=None, tags=['Wild Boars'])
+def create_wild_boars() -> None:
+    """
+    Create a Wild Boar
+    """
+    pass
+
+
+@router.get('/boars/{boar_id}', response_model=Pet, tags=['Wild Boars'])
+def show_boar_by_id(boar_id: str = Path(..., alias='boarId')) -> Pet:
+    """
+    Info For a Specific Boar
+    """
+    pass
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/dependencies.py b/tests/data/expected/openapi/using_routers/using_routers_example/dependencies.py
new file mode 100644
index 0000000..ede6084
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/dependencies.py
@@ -0,0 +1,11 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import Path
+
+from .models import FatCats, Pet, SlimDogs, WildBoars
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/main.py b/tests/data/expected/openapi/using_routers/using_routers_example/main.py
new file mode 100644
index 0000000..b6de4f4
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/main.py
@@ -0,0 +1,29 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import fat_cats, slim_dogs, wild_boars
+
+app = FastAPI(
+    version='1.0.0',
+    title='Swagger Petstore',
+    license={'name': 'MIT'},
+    servers=[
+        {'url': '/'},
+        {'url': 'http://petstore.swagger.io/v1'},
+        {'url': 'http://localhost:8080/'},
+    ],
+)
+
+app.include_router(fat_cats.router)
+app.include_router(slim_dogs.router)
+app.include_router(wild_boars.router)
+
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/models.py b/tests/data/expected/openapi/using_routers/using_routers_example/models.py
new file mode 100644
index 0000000..ceb4515
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/models.py
@@ -0,0 +1,27 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+
+class Pet(BaseModel):
+    id: int
+    name: str
+    tag: Optional[str] = None
+
+
+class FatCats(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of fat cats')
+
+
+class SlimDogs(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of slim dogs')
+
+
+class WildBoars(BaseModel):
+    __root__: List[Pet] = Field(..., description='list of wild boars')
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/routers/fat_cats.py b/tests/data/expected/openapi/using_routers/using_routers_example/routers/fat_cats.py
new file mode 100644
index 0000000..77a7da4
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/routers/fat_cats.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Fat Cats'])
+
+
+@router.get('/cats', response_model=FatCats, tags=['Fat Cats'])
+def list_fat_cats(limit: Optional[int] = None) -> FatCats:
+    """
+    List All Fat Cats
+    """
+    pass
+
+
+@router.post('/cats', response_model=None, tags=['Fat Cats'])
+def create_fat_cats() -> None:
+    """
+    Create a Fat Cat
+    """
+    pass
+
+
+@router.get('/cats/{cat_id}', response_model=Pet, tags=['Fat Cats'])
+def show_cat_by_id(cat_id: str = Path(..., alias='catId')) -> Pet:
+    """
+    Info For a Specific Cat
+    """
+    pass
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/routers/slim_dogs.py b/tests/data/expected/openapi/using_routers/using_routers_example/routers/slim_dogs.py
new file mode 100644
index 0000000..776c622
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/routers/slim_dogs.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Slim Dogs'])
+
+
+@router.get('/dogs', response_model=SlimDogs, tags=['Slim Dogs'])
+def list_slim_dogs(limit: Optional[int] = None) -> SlimDogs:
+    """
+    List All Slim Dogs
+    """
+    pass
+
+
+@router.post('/dogs', response_model=None, tags=['Slim Dogs'])
+def create_slim_dogs() -> None:
+    """
+    Create a Slim Dog
+    """
+    pass
+
+
+@router.get('/dogs/{dog_id}', response_model=Pet, tags=['Slim Dogs'])
+def show_dog_by_id(dog_id: str = Path(..., alias='dogId')) -> Pet:
+    """
+    Info For a Specific Dog
+    """
+    pass
diff --git a/tests/data/expected/openapi/using_routers/using_routers_example/routers/wild_boars.py b/tests/data/expected/openapi/using_routers/using_routers_example/routers/wild_boars.py
new file mode 100644
index 0000000..b0a849e
--- /dev/null
+++ b/tests/data/expected/openapi/using_routers/using_routers_example/routers/wild_boars.py
@@ -0,0 +1,35 @@
+# generated by fastapi-codegen:
+#   filename:  using_routers_example.yaml
+#   timestamp: 2023-04-11T00:00:00+00:00
+
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(tags=['Wild Boars'])
+
+
+@router.get('/boars', response_model=WildBoars, tags=['Wild Boars'])
+def list_wild_boars(limit: Optional[int] = None) -> WildBoars:
+    """
+    List All Wild Boars
+    """
+    pass
+
+
+@router.post('/boars', response_model=None, tags=['Wild Boars'])
+def create_wild_boars() -> None:
+    """
+    Create a Wild Boar
+    """
+    pass
+
+
+@router.get('/boars/{boar_id}', response_model=Pet, tags=['Wild Boars'])
+def show_boar_by_id(boar_id: str = Path(..., alias='boarId')) -> Pet:
+    """
+    Info For a Specific Boar
+    """
+    pass
diff --git a/tests/data/modular_template/dependencies.jinja2 b/tests/data/modular_template/dependencies.jinja2
new file mode 100644
index 0000000..ef3149f
--- /dev/null
+++ b/tests/data/modular_template/dependencies.jinja2
@@ -0,0 +1 @@
+{{imports}}
\ No newline at end of file
diff --git a/tests/data/modular_template/main.jinja2 b/tests/data/modular_template/main.jinja2
new file mode 100644
index 0000000..8d6a33d
--- /dev/null
+++ b/tests/data/modular_template/main.jinja2
@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from .routers import {{ routers | join(", ") }}
+
+app = FastAPI(
+    {% if info %}
+    {% for key,value in info.items() %}
+    {% set info_value= value.__repr__() %}
+    {{ key }} = {{info_value}},
+    {% endfor %}
+    {% endif %}
+    )
+
+{% for router in routers -%}
+app.include_router({{router}}.router)
+{% endfor -%}
+
+@app.get("/")
+async def root():
+    return {"message": "Gateway of the App"}
diff --git a/tests/data/modular_template/routers.jinja2 b/tests/data/modular_template/routers.jinja2
new file mode 100644
index 0000000..0cec624
--- /dev/null
+++ b/tests/data/modular_template/routers.jinja2
@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from fastapi import APIRouter
+
+from ..dependencies import *
+
+router = APIRouter(
+    tags=['{{tag}}']
+    )
+
+{% for operation in operations %}
+{% if operation.tags[0] == tag %}
+@router.{{operation.type}}('{{operation.snake_case_path}}', response_model={{operation.response}}
+    {% if operation.additional_responses %}
+        , responses={
+            {% for status_code, models in operation.additional_responses.items() %}
+                '{{ status_code }}': {
+                {% for key, model in models.items() %}
+                    '{{ key }}': {{ model }}{% if not loop.last %},{% endif %}
+                {% endfor %}
+                }{% if not loop.last %},{% endif %}
+            {% endfor %}
+        }
+    {% endif %}
+    {% if operation.tags%}
+    , tags={{operation.tags}}
+    {% endif %})
+def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operation.return_type}}:
+    {%- if operation.summary %}
+    """
+    {{ operation.summary }}
+    """
+    {%- endif %}
+    pass
+{% endif %}
+{% endfor %}
\ No newline at end of file
diff --git a/tests/data/openapi/using_routers/using_routers_example.yaml b/tests/data/openapi/using_routers/using_routers_example.yaml
new file mode 100644
index 0000000..8b12cb7
--- /dev/null
+++ b/tests/data/openapi/using_routers/using_routers_example.yaml
@@ -0,0 +1,184 @@
+
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: /
+  - url: http://petstore.swagger.io/v1
+  - url: http://localhost:8080/
+paths:
+  /boars:
+    get:
+      summary: List All Wild Boars
+      operationId: listWildBoars
+      tags:
+        - Wild Boars
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of wild boars
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/WildBoars"
+    post:
+      summary: Create a Wild Boar
+      operationId: createWildBoars
+      tags:
+        - Wild Boars
+      responses:
+        '201':
+          description: Null response
+  /boars/{boarId}:
+    get:
+      summary: Info For a Specific Boar
+      operationId: showBoarById
+      tags:
+        - Wild Boars
+      parameters:
+        - name: boarId
+          in: path
+          required: true
+          description: The id of the boar to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /cats:
+    get:
+      summary: List All Fat Cats
+      operationId: listFatCats
+      tags:
+        - Fat Cats
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of fat cats
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FatCats"
+    post:
+      summary: Create a Fat Cat
+      operationId: createFatCats
+      tags:
+        - Fat Cats
+      responses:
+        '201':
+          description: Null response
+  /cats/{catId}:
+    get:
+      summary: Info For a Specific Cat
+      operationId: showCatById
+      tags:
+        - Fat Cats
+      parameters:
+        - name: catId
+          in: path
+          required: true
+          description: The id of the cat to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+  /dogs:
+    get:
+      summary: List All Slim Dogs
+      operationId: listSlimDogs
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: An array of slim dogs
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/SlimDogs"
+    post:
+      summary: Create a Slim Dog
+      operationId: createSlimDogs
+      tags:
+        - Slim Dogs
+      responses:
+        '201':
+          description: Null response
+  /dogs/{dogId}:
+    get:
+      summary: Info For a Specific Dog
+      operationId: showDogById
+      tags:
+        - Slim Dogs
+      parameters:
+        - name: dogId
+          in: path
+          required: true
+          description: The id of the dog to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pet"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+        tag:
+          type: string
+    FatCats:
+      type: array
+      description: list of fat cats
+      items:
+        $ref: "#/components/schemas/Pet"
+    SlimDogs:
+      type: array
+      description: list of slim dogs
+      items:
+        $ref: "#/components/schemas/Pet"
+    WildBoars:
+      type: array
+      description: list of wild boars
+      items:
+        $ref: "#/components/schemas/Pet"
\ No newline at end of file
diff --git a/tests/test_generate.py b/tests/test_generate.py
index 507d74b..095cf1c 100644
--- a/tests/test_generate.py
+++ b/tests/test_generate.py
@@ -11,11 +11,16 @@
 OPEN_API_SECURITY_TEMPLATE_DIR_NAME = Path('openapi') / 'custom_template_security'
 OPEN_API_REMOTE_REF_DIR_NAME = Path('openapi') / 'remote_ref'
 OPEN_API_DISABLE_TIMESTAMP_DIR_NAME = Path('openapi') / 'disable_timestamp'
+OPEN_API_USING_ROUTERS_DIR_NAME = Path('openapi') / 'using_routers'
 
 DATA_DIR = Path(__file__).parent / 'data'
 
 EXPECTED_DIR = DATA_DIR / 'expected'
 
+BUILTIN_MODULAR_TEMPLATE_DIR = DATA_DIR / 'modular_template'
+
+SPECIFIC_TAGS = 'Wild Boars, Fat Cats'
+
 
 @pytest.mark.parametrize(
     "oas_file", (DATA_DIR / OPEN_API_DEFAULT_TEMPLATE_DIR_NAME).glob("*.yaml")
@@ -111,3 +116,64 @@ def test_disable_timestamp(oas_file):
         assert [f.name for f in output_files] == [f.name for f in expected_files]
         for output_file, expected_file in zip(output_files, expected_files):
             assert output_file.read_text() == expected_file.read_text()
+
+
+@pytest.mark.parametrize(
+    "oas_file", (DATA_DIR / OPEN_API_USING_ROUTERS_DIR_NAME).glob("*.yaml")
+)
+@freeze_time("2023-04-11")
+def test_generate_using_routers(oas_file):
+    with TemporaryDirectory() as tmp_dir:
+        output_dir = Path(tmp_dir) / oas_file.stem
+        Path(output_dir / "routers").mkdir(parents=True, exist_ok=True)
+        generate_code(
+            input_name=oas_file.name,
+            input_text=oas_file.read_text(),
+            output_dir=output_dir,
+            template_dir=BUILTIN_MODULAR_TEMPLATE_DIR,
+            generate_routers=True,
+        )
+        expected_dir = EXPECTED_DIR / OPEN_API_USING_ROUTERS_DIR_NAME / oas_file.stem
+        output_files = sorted(list(output_dir.glob('*')))
+        expected_files = sorted(list(expected_dir.glob('*')))
+        assert [f.name for f in output_files] == [f.name for f in expected_files]
+        for output_file, expected_file in zip(output_files, expected_files):
+            if output_file.is_dir() and expected_file.is_dir():
+                output_inners = sorted(list((output_dir / output_file).glob('*')))
+                expected_inners = sorted(list((expected_dir / expected_file).glob('*')))
+                for output_inner, expected_inner in zip(output_inners, expected_inners):
+                    assert output_inner.read_text() == expected_inner.read_text()
+            else:
+                assert output_file.read_text() == expected_file.read_text()
+
+
+@pytest.mark.parametrize(
+    "oas_file", (DATA_DIR / OPEN_API_USING_ROUTERS_DIR_NAME).glob("*.yaml")
+)
+@freeze_time("2023-04-11")
+def test_generate_modify_specific_routers(oas_file):
+    test_dir = EXPECTED_DIR / 'openapi/modify_specific_routers/modified'
+    output_dir = Path(test_dir) / oas_file.stem
+    Path(output_dir / "routers").mkdir(parents=True, exist_ok=True)
+    generate_code(
+        input_name=oas_file.name,
+        input_text=oas_file.read_text(),
+        output_dir=output_dir,
+        template_dir=BUILTIN_MODULAR_TEMPLATE_DIR,
+        generate_routers=True,
+        specify_tags=SPECIFIC_TAGS,
+    )
+    expected_dir = (
+        EXPECTED_DIR / 'openapi/modify_specific_routers/expected' / oas_file.stem
+    )
+    output_files = sorted(list(output_dir.glob('*')))
+    expected_files = sorted(list(expected_dir.glob('*')))
+    assert [f.name for f in output_files] == [f.name for f in expected_files]
+    for output_file, expected_file in zip(output_files, expected_files):
+        if output_file.is_dir() and expected_file.is_dir():
+            output_inners = sorted(list((output_dir / output_file).glob('*')))
+            expected_inners = sorted(list((expected_dir / expected_file).glob('*')))
+            for output_inner, expected_inner in zip(output_inners, expected_inners):
+                assert output_inner.read_text() == expected_inner.read_text()
+        else:
+            assert output_file.read_text() == expected_file.read_text()