diff --git a/src/depiction/tools/process_spectra/evaluators.py b/src/depiction/tools/process_spectra/evaluators.py
new file mode 100644
index 0000000..1129b28
--- /dev/null
+++ b/src/depiction/tools/process_spectra/evaluators.py
@@ -0,0 +1,80 @@
+from functools import cached_property
+from numpy.typing import NDArray
+from typing import Protocol
+
+from depiction.parallel_ops import ParallelConfig
+from depiction.spectrum.peak_filtering import PeakFilteringType
+from depiction.tools.correct_baseline.config import BaselineCorrectionConfig
+from depiction.tools.correct_baseline.correct_baseline import CorrectBaseline
+from depiction.tools.filter_peaks.config import FilterPeaksConfig
+from depiction.tools.filter_peaks.filter_peaks import get_peak_filter
+from depiction.tools.pick_peaks.config import PickPeaksConfig
+from depiction.tools.pick_peaks.pick_peaks import get_peak_picker_from_config
+from depiction.tools.process_spectra.config import (
+    ProcessSpectraStepPickPeaks,
+    ProcessSpectraStepRemoveBaseline,
+    ProcessSpectraStepFilterPeaks,
+)
+
+
+class Evaluator(Protocol):
+    def evaluate(self, mz_arr: NDArray[float], int_arr: NDArray[float]) -> tuple[NDArray[float], NDArray[float]]:
+        raise NotImplementedError
+
+
+def get_evaluator(step_config) -> Evaluator:
+    match step_config:
+        case ProcessSpectraStepPickPeaks(pick=pick_peaks_config):
+            return EvaluatePickPeaks(config=pick_peaks_config)
+        case ProcessSpectraStepRemoveBaseline(baseline=baseline_config):
+            return EvaluateRemoveBaseline(config=baseline_config)
+        case ProcessSpectraStepFilterPeaks(filter=filter_peaks_config):
+            return EvaluateFilterPeaks(config=filter_peaks_config)
+        case _:
+            raise ValueError(f"Unsupported step config: {step_config}")
+
+
+class EvaluatePickPeaks(Evaluator):
+    def __init__(self, config: PickPeaksConfig) -> None:
+        self._config = config
+
+    @cached_property
+    def _picker(self):
+        return get_peak_picker_from_config(self._config)
+
+    def evaluate(self, mz_arr, int_arr):
+        return self._picker.pick_peaks(mz_arr, int_arr)
+
+
+class EvaluateRemoveBaseline(Evaluator):
+    def __init__(self, config: BaselineCorrectionConfig) -> None:
+        self._config = config
+
+    @cached_property
+    def _correct_baseline(self) -> CorrectBaseline:
+        return CorrectBaseline.from_variant(
+            parallel_config=ParallelConfig.no_parallelism(),
+            variant=self._config.baseline_variant,
+            window_size=self._config.window_size,
+            window_unit=self._config.window_unit,
+        )
+
+    def evaluate(self, mz_arr, int_arr):
+        int_arr_new = self._correct_baseline.evaluate_spectrum(mz_arr, int_arr)
+        return mz_arr, int_arr_new
+
+
+class EvaluateFilterPeaks(Evaluator):
+    def __init__(self, config: FilterPeaksConfig) -> None:
+        self._config = config
+
+    @cached_property
+    def _filter(self) -> PeakFilteringType:
+        return get_peak_filter(self._config)
+
+    def evaluate(self, mz_arr, int_arr):
+        # TODO this is going to be important, how to handle this, i think we really
+        #      need to remove the spectrum_mz_arr, spectrum_int_arr; but then it will
+        #      not be possible to implement some things anymore (e.g. relative to total TIC)
+        #       unless filters can request these info somehow
+        return self._filter.filter_peaks(mz_arr, int_arr, mz_arr, int_arr)
diff --git a/src/depiction/tools/process_spectra/process.py b/src/depiction/tools/process_spectra/process.py
index 313b3e9..92c8fad 100644
--- a/src/depiction/tools/process_spectra/process.py
+++ b/src/depiction/tools/process_spectra/process.py
@@ -1,6 +1,7 @@
+from depiction.parallel_ops import ParallelConfig
 from depiction.persistence.types import GenericReadFile, GenericWriteFile
 from depiction.tools.process_spectra.config import ProcessSpectraConfig
 
 
 def process_spectra(read_file: GenericReadFile, write_file: GenericWriteFile, config: ProcessSpectraConfig) -> None:
-    pass
+    parallel_config = ParallelConfig(n_jobs=config.n_jobs)