diff --git a/glotaran/io/preprocessor/__init__.py b/glotaran/io/preprocessor/__init__.py
new file mode 100644
index 000000000..f419c7669
--- /dev/null
+++ b/glotaran/io/preprocessor/__init__.py
@@ -0,0 +1,2 @@
+"""Tools for data pre-processing."""
+from glotaran.io.preprocessor.pipeline import PreProcessingPipeline
diff --git a/glotaran/io/preprocessor/pipeline.py b/glotaran/io/preprocessor/pipeline.py
new file mode 100644
index 000000000..c331b8008
--- /dev/null
+++ b/glotaran/io/preprocessor/pipeline.py
@@ -0,0 +1,88 @@
+"""A pre-processor pipeline for data."""
+from __future__ import annotations
+
+from typing import Annotated
+
+import xarray as xr
+from pydantic import BaseModel
+from pydantic import Field
+
+from glotaran.io.preprocessor.preprocessor import CorrectBaselineAverage
+from glotaran.io.preprocessor.preprocessor import CorrectBaselineValue
+
+PipelineAction = Annotated[
+    CorrectBaselineValue | CorrectBaselineAverage,
+    Field(discriminator="action"),
+]
+
+
+class PreProcessingPipeline(BaseModel):
+    """A pipeline for pre-processors."""
+
+    actions: list[PipelineAction] = Field(default_factory=list)
+
+    def apply(self, original: xr.DataArray) -> xr.DataArray:
+        """Apply all pre-processors on data.
+
+        Parameters
+        ----------
+        original: xr.DataArray
+            The data to process.
+
+        Returns
+        -------
+        xr.DataArray
+        """
+        result = original.copy()
+
+        for action in self.actions:
+            result = action.apply(result)
+        return result
+
+    def _push_action(self, action: PipelineAction):
+        """Push an action.
+
+        Parameters
+        ----------
+        action: PipelineAction
+            The action to push.
+        """
+        self.actions.append(action)
+
+    def correct_baseline_value(self, value: float) -> PreProcessingPipeline:
+        """Correct a dataset by subtracting baseline value.
+
+        Parameters
+        ----------
+        value: float
+            The value to subtract.
+
+        Returns
+        -------
+        PreProcessingPipeline
+        """
+        self._push_action(CorrectBaselineValue(value=value))
+        return self
+
+    def correct_baseline_average(
+        self,
+        select: dict[str, slice | list[int] | int] | None = None,
+        exclude: dict[str, slice | list[int] | int] | None = None,
+    ) -> PreProcessingPipeline:
+        """Correct a dataset by subtracting the average over a part of the data.
+
+        Parameters
+        ----------
+        select: dict[str, slice | list[int] | int] | None
+            The selection to average as dictionary of dimension and indexer.
+            The indexer can be a slice, a list or an integer value.
+        exclude: dict[str, slice | list[int] | int] | None
+            Excluded regions from the average as dictionary of dimension and indexer.
+            The indexer can be a slice, a list or an integer value.
+
+        Returns
+        -------
+        PreProcessingPipeline
+        """
+        self._push_action(CorrectBaselineAverage(exclude=exclude, select=select))
+        return self
diff --git a/glotaran/io/preprocessor/preprocessor.py b/glotaran/io/preprocessor/preprocessor.py
new file mode 100644
index 000000000..6d918a96e
--- /dev/null
+++ b/glotaran/io/preprocessor/preprocessor.py
@@ -0,0 +1,76 @@
+"""A pre-processor pipeline for data."""
+from __future__ import annotations
+
+import abc
+from typing import Literal
+
+import xarray as xr
+from pydantic import BaseModel
+
+
+class PreProcessor(BaseModel, abc.ABC):
+    """A base class for pre=processors."""
+
+    class Config:
+        """Config for BaseModel."""
+
+        arbitrary_types_allowed = True
+
+    @abc.abstractmethod
+    def apply(self, data: xr.DataArray) -> xr.DataArray:
+        """Apply the pre-processor.
+
+        Parameters
+        ----------
+        data: xr.DataArray
+            The data to process.
+
+        Returns
+        -------
+        xr.DataArray
+
+        .. # noqa: DAR202
+        """
+
+
+class CorrectBaselineValue(PreProcessor):
+    """Corrects a dataset by subtracting baseline value."""
+
+    action: Literal["baseline-value"] = "baseline-value"
+    value: float
+
+    def apply(self, data: xr.DataArray) -> xr.DataArray:
+        """Apply the pre-processor.
+
+        Parameters
+        ----------
+        data: xr.DataArray
+            The data to process.
+
+        Returns
+        -------
+        xr.DataArray
+        """
+        return data - self.value
+
+
+class CorrectBaselineAverage(PreProcessor):
+    """Corrects a dataset by subtracting the average over a part of the data."""
+
+    action: Literal["baseline-average"] = "baseline-average"
+    select: dict[str, slice | list[int] | int] | None = None
+    exclude: dict[str, slice | list[int] | int] | None = None
+
+    def apply(self, data: xr.DataArray) -> xr.DataArray:
+        """Apply the pre-processor.
+
+        Parameters
+        ----------
+        data: xr.DataArray
+            The data to process.
+
+        Returns
+        -------
+        xr.DataArray
+        """
+        return data - data.sel(self.select or {}).drop_sel(self.exclude or {}).mean()
diff --git a/glotaran/io/preprocessor/test/test_preprocessor.py b/glotaran/io/preprocessor/test/test_preprocessor.py
new file mode 100644
index 000000000..f6a6e283e
--- /dev/null
+++ b/glotaran/io/preprocessor/test/test_preprocessor.py
@@ -0,0 +1,44 @@
+import pytest
+import xarray as xr
+
+from glotaran.io.preprocessor import PreProcessingPipeline
+
+
+def test_correct_baseline_value():
+    pl = PreProcessingPipeline()
+    pl.correct_baseline_value(1)
+    data = xr.DataArray([[1]])
+    result = pl.apply(data)
+    assert result == data - 1
+
+
+@pytest.mark.parametrize("indexer", (slice(0, 2), [0, 1]))
+def test_correct_baseline_average(indexer: slice | list[int]):
+    pl = PreProcessingPipeline()
+    pl.correct_baseline_average(select={"dim_0": 0, "dim_1": indexer})
+    data = xr.DataArray([[1.1, 0.9]])
+    result = pl.apply(data)
+    assert (result == data - 1).all()
+
+
+def test_correct_baseline_average_exclude():
+    pl = PreProcessingPipeline()
+    pl.correct_baseline_average(select={"dim_0": 0}, exclude={"dim_1": 1})
+    data = xr.DataArray([[1.1, 0.9]])
+    result = pl.apply(data)
+    print(result)
+    assert (result == data - 1.1).all()
+
+
+def test_to_from_dict():
+    pl = PreProcessingPipeline()
+    pl.correct_baseline_value(1)
+    pl.correct_baseline_average({"dim_1": slice(0, 2)})
+    pl_dict = pl.dict()
+    assert pl_dict == {
+        "actions": [
+            {"action": "baseline-value", "value": 1.0},
+            {"action": "baseline-average", "select": {"dim_1": slice(0, 2)}, "exclude": None},
+        ]
+    }
+    assert PreProcessingPipeline.parse_obj(pl_dict) == pl
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 5982a1092..6502bdc94 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -12,6 +12,7 @@ numpy==1.23.5
 odfpy==1.4.1
 openpyxl==3.1.1
 pandas==1.5.3
+pydantic==1.10.2
 rich==13.3.1
 ruamel.yaml==0.17.21
 scipy==1.10.1
diff --git a/setup.cfg b/setup.cfg
index b08492677..3080b3f3c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -40,6 +40,7 @@ install_requires =
     odfpy>=1.4.1
     openpyxl>=3.0.10
     pandas>=1.3.4
+    pydantic>=1.10.2
     rich>=10.9.0
     ruamel.yaml>=0.17.17
     scipy>=1.7.2