diff --git a/apparun/gui/modules.py b/apparun/gui/modules.py
index 74f1130..c340904 100644
--- a/apparun/gui/modules.py
+++ b/apparun/gui/modules.py
@@ -1,15 +1,25 @@
 from __future__ import annotations
 
+import io
+import re
 import subprocess
-from typing import Annotated, Callable, List, Optional, TypeVar, Union
+from typing import Annotated, Any, Callable, Dict, List, Optional, TypeVar, Union
 
 import pandas as pd
+import requests
 import streamlit as st
-from pydantic import BaseModel, Field
+from PIL import Image
+from pydantic import BaseModel, Field, field_validator
 
-from apparun.gui.panels.base import InputScenarioFormPanel
-from apparun.gui.panels.output_dynamic import ScenarioComparisonDynamicOutputPanel
-from apparun.gui.panels.output_static import Markdown
+from apparun.gui.panels.base import *
+from apparun.gui.panels.base import (
+    InputPanel,
+    OutputPanel,
+    get_input_panel,
+    get_output_panel,
+)
+from apparun.gui.panels.output_dynamic import *
+from apparun.gui.panels.output_static import *
 from apparun.impact_model import ImpactModel
 
 PandasDataFrame = TypeVar("pd.core.frame.DataFrame")
@@ -19,19 +29,29 @@ class Module(BaseModel):
     name: Optional[str] = None
     lca_data_path: Optional[str] = None
     impact_model_path: Optional[str] = None
-    input_panel: Optional[
-        Annotated[InputScenarioFormPanel, Field(discriminator="type")]
-    ] = None
-    output_panels: List[
-        Annotated[
-            Union[ScenarioComparisonDynamicOutputPanel, Markdown],
-            Field(discriminator="type"),
-        ]
-    ]
+    input_panel: Optional[InputPanel] = None
+    output_panels: List[OutputPanel]
     cols: Optional[Callable] = None
     lca_data: Optional[PandasDataFrame] = None
     impact_model: Optional[ImpactModel] = None
 
+    @field_validator("input_panel", mode="before")
+    @classmethod
+    def build_input_panel(
+        cls, panel: Optional[Dict[Any]] = None
+    ) -> Optional[InputPanel]:
+        if panel is None:
+            return None
+        return get_input_panel(panel["type"])(**panel)
+
+    @field_validator("output_panels", mode="before")
+    @classmethod
+    def build_output_panels(cls, panels: List[Dict[Any]]) -> List[OutputPanel]:
+        return [
+            get_output_panel(output_panel["type"])(**output_panel)
+            for output_panel in panels
+        ]
+
     def __init__(self, **args):
         super().__init__(**args)
         self.lca_data = (
@@ -77,14 +97,26 @@ def run(self):
         else:
             with self.output_col:
                 for output_panel in self.output_panels:
-                    output_panel.run()
+                    output_panel.run(
+                        impact_model=self.impact_model, lca_data=self.lca_data
+                    )
 
 
 class GUI(BaseModel):
     name: Optional[str] = None
+    favicon_path: Optional[str] = None
     modules: List[Module]
 
     def setup_layout(self):
+        favicon = None
+        if self.favicon_path is not None:
+            if re.match(r"https?://.*", self.favicon_path):
+                favicon = Image.open(
+                    io.BytesIO(requests.get(self.favicon_path, stream=True).content)
+                )
+            else:
+                favicon = Image.open(self.favicon_path)
+        st.set_page_config(page_title=self.name, page_icon=favicon)
         st.html(
             """
             <style>
diff --git a/apparun/gui/panels/base.py b/apparun/gui/panels/base.py
index 9fe7627..79bf1d1 100644
--- a/apparun/gui/panels/base.py
+++ b/apparun/gui/panels/base.py
@@ -11,6 +11,65 @@
 ACTION_ADD = "add"
 ACTION_CLEAR = "clear"
 
+INPUT_PANELS = {}
+OUTPUT_PANELS = {}
+
+
+def register_panel(panel_type: str):
+    """
+    This decorator registers a new Panel class in PANELS registry.
+    :param panel_type: new Panel's type name
+    :return: new Panel class
+    """
+
+    def decorator(decorated_class):
+        if issubclass(decorated_class, OutputPanel):
+            if panel_type not in OUTPUT_PANELS:
+                OUTPUT_PANELS[panel_type] = decorated_class
+            return decorated_class
+        if issubclass(decorated_class, InputPanel):
+            if panel_type not in INPUT_PANELS:
+                INPUT_PANELS[panel_type] = decorated_class
+            return decorated_class
+        msg = f"Custom panel {panel_type} must inherit from InputPanel or OutputPanel."
+        raise TypeError(msg)
+
+    return decorator
+
+
+def get_input_panel(panel_type: str):
+    """
+    Get a registered InputPanel class by type.
+    :param panel_type: type of the desired input panel.
+    :return: registered InputPanel class corresponding to the type.
+    """
+    return INPUT_PANELS[panel_type]
+
+
+def get_output_panel(panel_type: str):
+    """
+    Get a registered OutputPanel class by type.
+    :param panel_type: type of the desired output panel.
+    :return: registered OutputPanel class corresponding to the type.
+    """
+    return OUTPUT_PANELS[panel_type]
+
+
+def registered_input_panels() -> List[str]:
+    """
+    Get a list of registered InputPanel types.
+    :return: list of registered InputPanel types.
+    """
+    return list(INPUT_PANELS.keys())
+
+
+def registered_output_panels() -> List[str]:
+    """
+    Get a list of registered OutputPanel types.
+    :return: list of registered OutputPanel types.
+    """
+    return list(OUTPUT_PANELS.keys())
+
 
 class Panel(BaseModel):
     _state: Dict[Any, Any] = {}
@@ -60,7 +119,7 @@ def get_results(
 class StaticOutputPanel(OutputPanel):
     type: Literal["static_output_panel"]
 
-    def run(self):
+    def run(self, impact_model: ImpactModel = None, lca_data: pd.DataFrame = None):
         return
 
 
@@ -76,8 +135,9 @@ def submit(self):
         return
 
 
+@register_panel("input_scenario_form_panel")
 class InputScenarioFormPanel(InputPanel):
-    fields: List[Dict[str, Any]]
+    fields: Optional[List[Dict[str, Any]]] = []
     type: Literal["input_scenario_form_panel"]
 
     def __init__(self, **args):
diff --git a/apparun/gui/panels/output_dynamic.py b/apparun/gui/panels/output_dynamic.py
index 1bc1428..339db36 100644
--- a/apparun/gui/panels/output_dynamic.py
+++ b/apparun/gui/panels/output_dynamic.py
@@ -3,11 +3,17 @@
 import pandas as pd
 import streamlit as st
 
-from apparun.gui.panels.base import ACTION_ADD, ACTION_CLEAR, DynamicOutputPanel
+from apparun.gui.panels.base import (
+    ACTION_ADD,
+    ACTION_CLEAR,
+    DynamicOutputPanel,
+    register_panel,
+)
 from apparun.impact_model import ImpactModel
 from apparun.results import ImpactModelResult, ScenarioComparisonResult
 
 
+@register_panel("scenario_comparison_dynamic_output_panel")
 class ScenarioComparisonDynamicOutputPanel(DynamicOutputPanel):
     type: Literal["scenario_comparison_dynamic_output_panel"]
     result: Optional[ImpactModelResult] = None
diff --git a/apparun/gui/panels/output_static.py b/apparun/gui/panels/output_static.py
index 212a181..9e7b48c 100644
--- a/apparun/gui/panels/output_static.py
+++ b/apparun/gui/panels/output_static.py
@@ -1,14 +1,17 @@
 from typing import Literal
 
+import pandas as pd
 import streamlit as st
 
-from apparun.gui.panels.base import StaticOutputPanel
+from apparun.gui.panels.base import StaticOutputPanel, register_panel
+from apparun.impact_model import ImpactModel
 from apparun.results import ImpactModelResult
 
 
+@register_panel("markdown")
 class Markdown(StaticOutputPanel):
     type: Literal["markdown"]
     message: str
 
-    def run(self):
+    def run(self, impact_model: ImpactModel = None, lca_data: pd.DataFrame = None):
         st.markdown(f"{self.message}")
diff --git a/samples/conf/custom_gui.yaml b/samples/conf/custom_gui.yaml
new file mode 100644
index 0000000..67b06f9
--- /dev/null
+++ b/samples/conf/custom_gui.yaml
@@ -0,0 +1,21 @@
+name: "GUI with custom panels"
+favicon_path: "https://www.cea.fr/PublishingImages/cea.jpg"
+modules:
+  - name: "Rude markdown"
+    output_panels:
+      - type: markdown
+        message: "This is using a panel built in Appa Run."
+  - name: "Polite markdown"
+    output_panels:
+      - type: polite_markdown
+        message: "This is using a panel built in an external script."
+  - name: "Scenario comparison by phase"
+    impact_model_path: "samples/impact_models/nvidia_ai_gpu_chip.yaml"
+    input_panel:
+      type: input_scenario_from_file_panel
+      name: "GPU parameters"
+    output_panels:
+      - type: batch_scenario_comparison_dynamic_output_panel
+        y: EFV3_CLIMATE_CHANGE
+        hue: phase
+        by_property: "phase"
\ No newline at end of file
diff --git a/samples/conf/parameters_sets/scenario_A.yaml b/samples/conf/parameters_sets/scenario_A.yaml
new file mode 100644
index 0000000..23dab9d
--- /dev/null
+++ b/samples/conf/parameters_sets/scenario_A.yaml
@@ -0,0 +1,3 @@
+lifespan: 3
+architecture: Maxwell
+cuda_core: 2048
\ No newline at end of file
diff --git a/samples/conf/parameters_sets/scenario_B.yaml b/samples/conf/parameters_sets/scenario_B.yaml
new file mode 100644
index 0000000..3c90075
--- /dev/null
+++ b/samples/conf/parameters_sets/scenario_B.yaml
@@ -0,0 +1,3 @@
+lifespan: 3
+architecture: Pascal
+cuda_core: 1024
\ No newline at end of file
diff --git a/samples/conf/sample_gui.yaml b/samples/conf/sample_gui.yaml
index c52994d..49a4083 100644
--- a/samples/conf/sample_gui.yaml
+++ b/samples/conf/sample_gui.yaml
@@ -1,4 +1,5 @@
 name: "Preconfigured tool for NVIDIA AI GPU"
+favicon_path: "https://www.cea.fr/PublishingImages/cea.jpg"
 modules:
   - impact_model_path: "samples/impact_models/nvidia_ai_gpu_chip.yaml"
     name: "Scenario comparison by phase"
diff --git a/samples/scripts/custom_gui.py b/samples/scripts/custom_gui.py
new file mode 100644
index 0000000..ec48a6c
--- /dev/null
+++ b/samples/scripts/custom_gui.py
@@ -0,0 +1,74 @@
+from typing import Literal
+
+import pandas as pd
+import streamlit as st
+import yaml
+
+from apparun.cli.main import generate_gui
+from apparun.gui.panels.base import (
+    ACTION_ADD,
+    InputScenarioFormPanel,
+    StaticOutputPanel,
+    register_panel,
+)
+from apparun.gui.panels.output_dynamic import ScenarioComparisonDynamicOutputPanel
+from apparun.impact_model import ImpactModel
+
+
+@register_panel("polite_markdown")
+class PoliteMarkdown(StaticOutputPanel):
+    type: Literal["polite_markdown"]
+    message: str
+
+    def run(self, impact_model: ImpactModel = None, lca_data: pd.DataFrame = None):
+        st.markdown(f"{self.message}\n\nKind regards.")
+
+
+@register_panel("batch_scenario_comparison_dynamic_output_panel")
+class BatchScenarioComparisonDynamicOutputPanel(ScenarioComparisonDynamicOutputPanel):
+    type: Literal["batch_scenario_comparison_dynamic_output_panel"]
+
+    def __init__(self, **args):
+        super().__init__(**args)
+        self._state["scenarios"] = {}
+
+    def run(
+        self,
+        entry_data,
+        impact_model: ImpactModel = None,
+        lca_data: pd.DataFrame = None,
+    ):
+        if entry_data["action"] == ACTION_ADD:
+            scenario_scores = self.get_results(
+                entry_data["parameters"], impact_model, lca_data
+            )
+            fig = self.result.get_figure(scenario_scores)
+            st.plotly_chart(fig)
+
+
+@register_panel("input_scenario_from_file_panel")
+class ScenarioFromFilePanel(InputScenarioFormPanel):
+    type: Literal["input_scenario_from_file_panel"]
+
+    def run(self):
+        self.st_component = st.form(self._uuid)
+
+        if self.name is not None:
+            self.st_component.markdown(f"### {self.name}")
+
+        uploaded_files = self.st_component.file_uploader(
+            "Upload parameters", accept_multiple_files="directory", type="yaml"
+        )
+        for uploaded_file in uploaded_files:
+            scenario_name = uploaded_file.name.split("/")[-1].split(".")[:-1][0]
+            self._state["parameters"][scenario_name] = yaml.safe_load(
+                uploaded_file.getvalue()
+            )
+
+        scenarios_add = self.st_component.form_submit_button("Compute")
+
+        if scenarios_add and len(uploaded_files) > 0:
+            self._state["action"] = ACTION_ADD
+
+
+generate_gui("samples/conf/custom_gui.yaml")
diff --git a/tests/data/cea.jpg b/tests/data/cea.jpg
new file mode 100644
index 0000000..84c1b5e
Binary files /dev/null and b/tests/data/cea.jpg differ
diff --git a/tests/data/conf/functional_gui.yaml b/tests/data/conf/functional_gui.yaml
index abdba25..eef0065 100644
--- a/tests/data/conf/functional_gui.yaml
+++ b/tests/data/conf/functional_gui.yaml
@@ -1,4 +1,5 @@
 name: "Preconfigured tool for NVIDIA AI GPU"
+favicon_path: "https://www.cea.fr/PublishingImages/cea.jpg"
 modules:
   - name: "Random explanation"
     output_panels:
diff --git a/tests/data/conf/functional_gui_local_logo.yaml b/tests/data/conf/functional_gui_local_logo.yaml
new file mode 100644
index 0000000..8c34495
--- /dev/null
+++ b/tests/data/conf/functional_gui_local_logo.yaml
@@ -0,0 +1,7 @@
+name: "Preconfigured tool for NVIDIA AI GPU"
+favicon_path: "tests/data/cea.jpg"
+modules:
+  - name: "Random explanation"
+    output_panels:
+      - type: markdown
+        message: "**Lorem ipsum** dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
diff --git a/tests/end_to_end/test_gui.py b/tests/end_to_end/test_gui.py
index 1c44a90..613092a 100644
--- a/tests/end_to_end/test_gui.py
+++ b/tests/end_to_end/test_gui.py
@@ -2,8 +2,13 @@
 This module contains the tests related to the gui command.
 """
 
+import pytest
+from PIL import UnidentifiedImageError
 from streamlit.testing.v1 import AppTest
 
+from apparun.cli.main import load_yaml
+from apparun.gui.modules import GUI
+
 
 def run_test_gui():
     from apparun.cli.main import generate_gui
@@ -20,3 +25,26 @@ def test_streamlit_app_is_deploying():
     at.run()
     # This app should generate three md widgets: one title, one header, one text block.
     assert len(at.markdown) == 3
+
+
+def test_favicons():
+    """
+    Check that local and remote favicon can be loaded.
+    """
+    remote_logo_gui_config = load_yaml("tests/data/conf/functional_gui.yaml", "r")
+    gui = GUI(**remote_logo_gui_config)
+    try:
+        gui.setup_layout()
+    except UnidentifiedImageError:
+        msg = f"Cannot load remote favicon {gui.favicon_path}"
+        pytest.fail(msg)
+
+    local_logo_gui_config = load_yaml(
+        "tests/data/conf/functional_gui_local_logo.yaml", "r"
+    )
+    gui = GUI(**local_logo_gui_config)
+    try:
+        gui.setup_layout()
+    except UnidentifiedImageError:
+        msg = f"Cannot load local favicon {gui.favicon_path}"
+        pytest.fail(msg)