diff --git a/src/teampulse/resolver.py b/src/teampulse/resolver.py
new file mode 100644
index 0000000..dfef0b9
--- /dev/null
+++ b/src/teampulse/resolver.py
@@ -0,0 +1,38 @@
+import json
+from pathlib import Path
+
+from playwright.sync_api import Page
+
+
+class Resolver:
+    def __init__(self, cache_path: Path, page: Page):
+        self._cache_path = cache_path
+        self._page = page
+        self._cache: dict[str, str] = self._load_cache()
+
+    def resolve(self, display_name: str) -> str:
+        if display_name in self._cache:
+            return self._cache[display_name]
+
+        email = self._extract_email_from_profile(display_name)
+        if email is None:
+            return "<nicht auflösbar>"
+
+        self._cache[display_name] = email
+        self._save_cache()
+        return email
+
+    def _load_cache(self) -> dict[str, str]:
+        if not self._cache_path.exists():
+            return {}
+        return json.loads(self._cache_path.read_text(encoding="utf-8"))
+
+    def _save_cache(self) -> None:
+        self._cache_path.write_text(
+            json.dumps(self._cache, ensure_ascii=False, indent=2),
+            encoding="utf-8",
+        )
+
+    def _extract_email_from_profile(self, display_name: str) -> str | None:
+        # Implemented in Task 8 — browser interaction with Teams profile cards
+        raise NotImplementedError
diff --git a/tests/test_resolver_cache.py b/tests/test_resolver_cache.py
new file mode 100644
index 0000000..2ac37f9
--- /dev/null
+++ b/tests/test_resolver_cache.py
@@ -0,0 +1,69 @@
+import json
+from pathlib import Path
+from unittest.mock import MagicMock
+
+import pytest
+
+from teampulse.resolver import Resolver
+
+
+@pytest.fixture
+def cache_path(tmp_path):
+    return tmp_path / "cache.json"
+
+
+def test_resolve_returns_email_from_cache(cache_path):
+    cache_path.write_text(json.dumps({"Max Mustermann": "m.mustermann@company.com"}))
+    resolver = Resolver(cache_path=cache_path, page=MagicMock())
+    assert resolver.resolve("Max Mustermann") == "m.mustermann@company.com"
+
+
+def test_resolve_unknown_name_calls_browser(cache_path):
+    cache_path.write_text(json.dumps({}))
+    mock_page = MagicMock()
+    resolver = Resolver(cache_path=cache_path, page=mock_page)
+    resolver._extract_email_from_profile = MagicMock(return_value="k.huber@company.com")
+
+    result = resolver.resolve("Klaus Huber")
+
+    resolver._extract_email_from_profile.assert_called_once_with("Klaus Huber")
+    assert result == "k.huber@company.com"
+
+
+def test_resolve_caches_newly_resolved_email(cache_path):
+    cache_path.write_text(json.dumps({}))
+    resolver = Resolver(cache_path=cache_path, page=MagicMock())
+    resolver._extract_email_from_profile = MagicMock(return_value="k.huber@company.com")
+
+    resolver.resolve("Klaus Huber")
+
+    saved = json.loads(cache_path.read_text())
+    assert saved["Klaus Huber"] == "k.huber@company.com"
+
+
+def test_resolve_unresolvable_returns_placeholder(cache_path):
+    cache_path.write_text(json.dumps({}))
+    resolver = Resolver(cache_path=cache_path, page=MagicMock())
+    resolver._extract_email_from_profile = MagicMock(return_value=None)
+
+    result = resolver.resolve("Unknown Person")
+    assert result == "<nicht auflösbar>"
+
+
+def test_resolve_does_not_cache_unresolvable(cache_path):
+    cache_path.write_text(json.dumps({}))
+    resolver = Resolver(cache_path=cache_path, page=MagicMock())
+    resolver._extract_email_from_profile = MagicMock(return_value=None)
+
+    resolver.resolve("Unknown Person")
+
+    saved = json.loads(cache_path.read_text())
+    assert "Unknown Person" not in saved
+
+
+def test_creates_cache_file_if_missing(tmp_path):
+    cache_path = tmp_path / "nonexistent.json"
+    resolver = Resolver(cache_path=cache_path, page=MagicMock())
+    resolver._extract_email_from_profile = MagicMock(return_value="a@b.com")
+    resolver.resolve("Test User")
+    assert cache_path.exists()