diff --git a/src/auto_reverse/store.py b/src/auto_reverse/store.py
index 7a310f6..d84df52 100644
--- a/src/auto_reverse/store.py
+++ b/src/auto_reverse/store.py
@@ -1,9 +1,15 @@
 from __future__ import annotations
 
 import re
+import threading
+from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
+from auto_reverse.models import EndpointRecord, Signature, status_class
+
 if TYPE_CHECKING:
+    from collections.abc import Callable
+
     from auto_reverse.models import CapturedFlow
 
 _UUID = re.compile(r"^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$")
@@ -62,3 +68,80 @@ class ScopeFilter:
             return False
         ctype = flow.resp_headers.get("content-type", "").lower()
         return not ctype.startswith(("text/css", "image/", "font/", "application/javascript"))
+
+
+MAX_SAMPLES = 5
+
+
+@dataclass
+class IngestResult:
+    in_scope: bool
+    is_new: bool
+    signature: Signature | None
+
+
+class FlowStore:
+    """Thread-safe store: dedup by signature, retain bounded samples per endpoint."""
+
+    def __init__(
+        self,
+        scope: ScopeFilter,
+        on_new_signature: Callable[[Signature], None] | None = None,
+    ) -> None:
+        self._scope = scope
+        self._on_new = on_new_signature
+        self._lock = threading.Lock()
+        self._records: dict[Signature, EndpointRecord] = {}
+        self._samples: dict[Signature, list[CapturedFlow]] = {}
+
+    def signature_of(self, flow: CapturedFlow) -> Signature:
+        return Signature(
+            method=flow.method.upper(),
+            host=flow.host,
+            path_template=path_template(flow.path),
+            status_class=status_class(flow.status),
+        )
+
+    def ingest(self, flow: CapturedFlow) -> IngestResult:
+        if not self._scope.is_in_scope(flow):
+            return IngestResult(in_scope=False, is_new=False, signature=None)
+        sig = self.signature_of(flow)
+        with self._lock:
+            is_new = sig not in self._records
+            if is_new:
+                self._records[sig] = EndpointRecord(signature=sig)
+                self._samples[sig] = []
+            record = self._records[sig]
+            record.sample_count += 1
+            record.query_params.update(self._query_keys(flow))
+            samples = self._samples[sig]
+            if len(samples) < MAX_SAMPLES:
+                samples.append(flow)
+        if is_new and self._on_new is not None:
+            self._on_new(sig)
+        return IngestResult(in_scope=True, is_new=is_new, signature=sig)
+
+    @staticmethod
+    def _query_keys(flow: CapturedFlow) -> set[str]:
+        return set(flow.query.keys())
+
+    def endpoints(self) -> list[EndpointRecord]:
+        with self._lock:
+            return list(self._records.values())
+
+    def samples(self, sig: Signature) -> list[CapturedFlow]:
+        with self._lock:
+            return list(self._samples.get(sig, []))
+
+    def get(self, sig: Signature) -> EndpointRecord | None:
+        with self._lock:
+            return self._records.get(sig)
+
+    def search(self, query: str) -> list[EndpointRecord]:
+        q = query.lower()
+        with self._lock:
+            return [
+                r for r in self._records.values()
+                if q in r.signature.path_template.lower()
+                or q in r.signature.method.lower()
+            ]
diff --git a/tests/test_store.py b/tests/test_store.py
index 995a05e..825b53e 100644
--- a/tests/test_store.py
+++ b/tests/test_store.py
@@ -1,4 +1,5 @@
-from auto_reverse.store import path_template
+from auto_reverse.models import CapturedFlow, Signature
+from auto_reverse.store import FlowStore, ScopeFilter, path_template
 
 
 def test_collapses_numeric_ids():
@@ -21,3 +22,46 @@ def test_keeps_short_words():
 def test_root_and_empty():
     assert path_template("/") == "/"
     assert path_template("") == "/"
+
+
+def _post(host: str, path: str, body: bytes) -> CapturedFlow:
+    return CapturedFlow(
+        method="POST", host=host, path=path, query={},
+        req_headers={"content-type": "application/json"}, req_body=body,
+        status=201, resp_headers={"content-type": "application/json"},
+        resp_body=b'{"ok": true}', timestamp=0.0,
+    )
+
+
+def test_ingest_new_signature_returns_true_once():
+    store = FlowStore(ScopeFilter(target_hosts={"ex.com"}))
+    assert store.ingest(_post("ex.com", "/api/cart/1", b'{"q": 1}')).is_new is True
+    # same template, different id -> not new
+    assert store.ingest(_post("ex.com", "/api/cart/2", b'{"q": 2}')).is_new is False
+    assert len(store.endpoints()) == 1
+
+
+def test_out_of_scope_flow_ignored():
+    store = FlowStore(ScopeFilter(target_hosts={"ex.com"}))
+    result = store.ingest(_post("other.com", "/x", b"{}"))
+    assert result.is_new is False
+    assert result.in_scope is False
+    assert store.endpoints() == []
+
+
+def test_new_signature_callback_fires_with_signature():
+    seen: list[Signature] = []
+    store = FlowStore(ScopeFilter(target_hosts={"ex.com"}), on_new_signature=seen.append)
+    store.ingest(_post("ex.com", "/api/cart/1", b"{}"))
+    store.ingest(_post("ex.com", "/api/cart/2", b"{}"))
+    assert len(seen) == 1
+    assert seen[0].path_template == "/api/cart/{id}"
+
+
+def test_search_filters_by_substring():
+    store = FlowStore(ScopeFilter(target_hosts={"ex.com"}))
+    store.ingest(_post("ex.com", "/api/cart/1", b"{}"))
+    store.ingest(_post("ex.com", "/api/login", b"{}"))
+    results = store.search("cart")
+    assert len(results) == 1
+    assert results[0].signature.path_template == "/api/cart/{id}"