diff --git a/personal_mnemonic_medium/v2/domain/diff_determiner/base_diff_determiner.py b/personal_mnemonic_medium/v2/domain/diff_determiner/base_diff_determiner.py
index 558a9338..62ff37fe 100644
--- a/personal_mnemonic_medium/v2/domain/diff_determiner/base_diff_determiner.py
+++ b/personal_mnemonic_medium/v2/domain/diff_determiner/base_diff_determiner.py
@@ -1,14 +1,23 @@
-from collections.abc import Sequence
-from typing import Protocol
+from collections.abc import Mapping, Sequence
+from pathlib import Path
+from typing import Generic, Protocol, TypeVar
 
 from personal_mnemonic_medium.v2.domain.prompt_destination.base_prompt_destination import (
     PromptDestinationCommand,
 )
 
+from ..prompt_destination.destination_commands import (
+    DeletePrompts,
+    PushPrompts,
+)
 from ..prompts.base_prompt import BasePrompt
 
+K = TypeVar("K")
+T = TypeVar("T")
+S = TypeVar("S")
+
 
-class BaseSyncer(Protocol):
+class BaseDiffDeterminer(Protocol):
     def sync(
         self,
         source_prompts: Sequence[BasePrompt],
@@ -17,7 +26,60 @@ def sync(
         ...
 
 
-class FakeDiffDeterminer(BaseSyncer):
+class GeneralSyncer(Generic[K, T, S]):
+    def __init__(
+        self, source: Mapping[K, T], destination: Mapping[K, S]
+    ):
+        self.source = source
+        self.destination = destination
+
+    def only_in_source(self) -> Sequence[T]:
+        return [
+            value
+            for key, value in self.source.items()
+            if key not in self.destination
+        ]
+
+    def only_in_destination(self) -> Sequence[S]:
+        return [
+            value
+            for key, value in self.destination.items()
+            if key not in self.source
+        ]
+
+
+class PromptDiffDeterminer(BaseDiffDeterminer):
+    def __init__(self, tmp_read_dir: Path, tmp_write_dir: Path):
+        # TODO: https://github.com/MartinBernstorff/personal-mnemonic-medium/issues/308 refactor: get rid of tmp_read_dir and tmp_write_dir
+        self.tmp_read_dir = tmp_read_dir
+        self.tmp_read_dir.mkdir(exist_ok=True)
+
+        self.tmp_write_dir = tmp_write_dir
+        self.tmp_write_dir.mkdir(exist_ok=True)
+
+    def sync(
+        self,
+        source_prompts: Sequence[BasePrompt],
+        destination_prompts: Sequence[BasePrompt],
+    ) -> Sequence[PromptDestinationCommand]:
+        syncer = GeneralSyncer(
+            source={prompt.uid: prompt for prompt in source_prompts},
+            destination={
+                prompt.uid: prompt for prompt in destination_prompts
+            },
+        )
+
+        return [
+            DeletePrompts(syncer.only_in_destination()),
+            PushPrompts(
+                syncer.only_in_source(),
+                tmp_write_dir=self.tmp_write_dir,
+                tmp_read_dir=self.tmp_read_dir,
+            ),
+        ]
+
+
+class FakeDiffDeterminer(BaseDiffDeterminer):
     def sync(
         self,
         source_prompts: Sequence[BasePrompt],
diff --git a/personal_mnemonic_medium/v2/domain/diff_determiner/test_diff_determiner.py b/personal_mnemonic_medium/v2/domain/diff_determiner/test_diff_determiner.py
new file mode 100644
index 00000000..0dea7042
--- /dev/null
+++ b/personal_mnemonic_medium/v2/domain/diff_determiner/test_diff_determiner.py
@@ -0,0 +1,45 @@
+from pathlib import Path
+
+from ..prompt_destination.destination_commands import (
+    DeletePrompts,
+    PushPrompts,
+)
+from ..prompts.qa_prompt import QAPrompt
+from .base_diff_determiner import GeneralSyncer, PromptDiffDeterminer
+
+
+def test_diff_determiner():
+    syncer = GeneralSyncer(
+        source={"a": 1, "b": 2}, destination={"b": "2", "c": "3"}
+    )
+
+    assert syncer.only_in_source() == [1]
+    assert syncer.only_in_destination() == ["3"]
+
+
+def test_prompt_diff_determiner(tmp_path: Path):
+    syncer = PromptDiffDeterminer(
+        tmp_read_dir=tmp_path, tmp_write_dir=tmp_path
+    )
+
+    source_prompts = [
+        QAPrompt(question="a", answer="a"),
+        QAPrompt(question="b", answer="b"),
+    ]
+    destination_prompts = [
+        QAPrompt(question="b", answer="b"),
+        QAPrompt(question="c", answer="c"),
+    ]
+
+    diff = syncer.sync(
+        source_prompts=source_prompts,
+        destination_prompts=destination_prompts,
+    )
+    assert diff == [
+        DeletePrompts([QAPrompt(question="c", answer="c")]),
+        PushPrompts(
+            [QAPrompt(question="a", answer="a")],
+            tmp_write_dir=tmp_path,
+            tmp_read_dir=tmp_path,
+        ),
+    ]
diff --git a/personal_mnemonic_medium/v2/presentation/cli.py b/personal_mnemonic_medium/v2/presentation/cli.py
index 633c17b9..386002c3 100644
--- a/personal_mnemonic_medium/v2/presentation/cli.py
+++ b/personal_mnemonic_medium/v2/presentation/cli.py
@@ -15,7 +15,7 @@
 from ...main import get_env
 from ..data_access.ankiconnect_gateway import AnkiConnectGateway
 from ..domain.diff_determiner.base_diff_determiner import (
-    FakeDiffDeterminer,
+    PromptDiffDeterminer,
 )
 from ..domain.prompt_destination.anki_connect.ankiconnect_destination import (
     AnkiConnectDestination,
@@ -29,6 +29,7 @@
 
 
 def _sync_deck(deck_name: str):
+    # TODO: https://github.com/MartinBernstorff/personal-mnemonic-medium/issues/309 feat: use markdown promptsource
     source_prompts = FakePromptSource().get_prompts()
 
     destination = AnkiConnectDestination(
@@ -41,7 +42,9 @@ def _sync_deck(deck_name: str):
     )
     destination_prompts = destination.get_all_prompts()
 
-    update_commands = FakeDiffDeterminer().sync(
+    update_commands = PromptDiffDeterminer(
+        tmp_write_dir=Path("/tmp"), tmp_read_dir=Path("/tmp")
+    ).sync(
         source_prompts=source_prompts,
         destination_prompts=destination_prompts,
     )