diff --git a/app/api/v1/router.py b/app/api/v1/router.py
index e2cb7b4..557dea2 100644
--- a/app/api/v1/router.py
+++ b/app/api/v1/router.py
@@ -22,7 +22,7 @@ from pydantic import BaseModel, Field
 from ...auth import resolve_account_id
 from ...crypto import encrypt_creds
 from ...db import get_connection
-from ...idempotency import idempotency_key
+from ...idempotency import build_key, canonicalize_row, idempotency_key
 from ...mapping import (
     account_or_default,
     load_mapping,
@@ -63,7 +63,17 @@ def create_prezentari(
         mapping = load_mapping(conn, acct)
         for prez in req.prezentari:
             content = prez.model_dump()
-            key = idempotency_key(account_id, content)
+            # T9/OV-2: canonicalize_row inaintea build_key (odometru strip ".0", VIN upper).
+            # build_key aplica account_or_default(account_id) inainte de hash:
+            # None si 1 colapseaza la aceeasi cheie (canal API + canal import).
+            canon = canonicalize_row(content)
+            key = build_key(account_id, canon)
+            # Aplica normalizarea si in content (odometru canonicalizat inainte de validare, §3.4bis)
+            content.update({
+                "vin": canon["vin"],
+                "nr_inmatriculare": canon["nr_inmatriculare"],
+                "odometru_final": canon["odometru_final"],
+            })
             existing = conn.execute(
                 "SELECT id, status, id_prezentare FROM submissions WHERE idempotency_key=?",
                 (key,),
diff --git a/app/idempotency.py b/app/idempotency.py
index b395fb8..9e47438 100644
--- a/app/idempotency.py
+++ b/app/idempotency.py
@@ -2,6 +2,23 @@
 
 RAR nu are camp nr. comanda si accepta duplicate -> dedup-ul e in sarcina noastra
 (plan.md sect. 14). Hash stabil peste o reprezentare canonica a prezentarii.
+
+Treapta 2 (T9 + OV-2): extrage canonicalize_row + build_key ca helpere publice
+partajate intre canalul API si canalul import.
+  - canonicalize_row: normeaza VIN/nr/odometru (strip ".0" Excel coercion) INAINTE
+    de validare (§3.4bis) si INAINTE de cheie.
+  - build_key: aplica account_or_default INAINTE de hash (None si 1 => o cheie).
+
+OV-2 — skew account_id: routerul vechi pasa account_id AS-PASSED (None pe canal API
+fara auth). Randurile se stocau sub account_or_default=1, dar cheia includea None.
+Acelasi rand logic din import (account_id=1) dadea cheie diferita -> already_sent
+rata -> al doilea FINALIZATA. Fix: build_key normalizeaza INTOTDEAUNA la
+account_or_default inainte de hash.
+
+Migrare DB productie (OV-2): randurile existente cu cheie-None nu mai sunt gasite de
+build_key nou. Strategie documentata: dual-lookup la already_sent (incearca cheia
+noua, apoi cheia legacy). In dev nu exista date reale; la first-deploy productie
+se poate face recompute-keys o singura data.
 """
 
 from __future__ import annotations
@@ -20,10 +37,88 @@ def _op_identity(p: Any) -> str:
     return (get("cod_op_service", "") or "").strip()
 
 
+def canonicalize_row(raw: dict[str, Any]) -> dict[str, Any]:
+    """Normalizare canonica a unui rand brut. Apelata INAINTE de validare si de build_key.
+
+    - VIN, nr_inmatriculare: strip + upper.
+    - odometru_final: strip ".0" (Excel coercion numeric 123456.0 -> "123456").
+      Necesar ca validation._parse_int (isdigit()) sa nu respinga float-string.
+    - data_prestatie: strip (normalizarea la YYYY-MM-DD se face in parser).
+    - prestatii: pastrate ca-atare (rezolvarea e in resolve_prestatii).
+    """
+    # VIN
+    vin = (raw.get("vin") or "").strip().upper()
+
+    # Nr. inmatriculare
+    nr = (raw.get("nr_inmatriculare") or "").strip().upper()
+
+    # Odometru: strip ".0" Excel float coercion
+    odo_raw = raw.get("odometru_final")
+    if odo_raw is not None:
+        odo_s = str(odo_raw).strip()
+        # "123456.0" -> "123456"; "123456.50" nu (nu e coercion Excel pur)
+        if "." in odo_s:
+            before, after = odo_s.split(".", 1)
+            if after == "0" and before.lstrip("-").isdigit():
+                odo_s = before
+    else:
+        odo_s = ""
+
+    # Data (pastrata ca string; parsarea la YYYY-MM-DD e in parser)
+    data = str(raw.get("data_prestatie") or "").strip()
+
+    # Prestatii (copie superficiala; rezolvarea e upstream)
+    prestatii = list(raw.get("prestatii") or [])
+
+    return {
+        "vin": vin,
+        "nr_inmatriculare": nr,
+        "data_prestatie": data,
+        "odometru_final": odo_s,
+        "prestatii": prestatii,
+    }
+
+
+def build_key(account_id: int | None, canon: dict[str, Any]) -> str:
+    """SHA-256 partajat canal-API + canal-import.
+
+    Aplica account_or_default inainte de hash (OV-2): None si 1 colapseaza la
+    aceeasi cheie => acelasi rand logic din canale diferite nu se trimite de doua ori.
+    """
+    # Import local ca sa evitam import circular (mapping importa din idempotency via validator)
+    from .mapping import account_or_default
+    acct = account_or_default(account_id)
+    canonic = {
+        "account_id": acct,
+        "vin": canon.get("vin", ""),
+        "nr_inmatriculare": canon.get("nr_inmatriculare", ""),
+        "data_prestatie": canon.get("data_prestatie"),
+        "odometru_final": canon.get("odometru_final", ""),
+        "prestatii": sorted(_op_identity(p) for p in (canon.get("prestatii") or [])),
+    }
+    blob = json.dumps(canonic, sort_keys=True, ensure_ascii=False, separators=(",", ":"))
+    return hashlib.sha256(blob.encode("utf-8")).hexdigest()
+
+
 def idempotency_key(account_id: int | None, prezentare: dict[str, Any]) -> str:
     """SHA-256 peste (account_id + campurile semnificative ale prezentarii).
 
+    Wrapper backward-compat peste canonicalize_row + build_key.
     Exclude obs si b64Image (cosmetice, nu definesc unicitatea declaratiei).
+
+    NOTA: dupa OV-2, account_id=None si account_id=1 produc ACEEASI cheie
+    (via account_or_default in build_key). Randuri vechi cu cheie-None nu sunt
+    acoperite automat — dual-lookup sau recompute-keys la migrare productie.
+    """
+    canon = canonicalize_row(prezentare)
+    return build_key(account_id, canon)
+
+
+def build_key_legacy(account_id: int | None, prezentare: dict[str, Any]) -> str:
+    """Cheia in formatul vechi (account_id AS-PASSED, fara canonicalize).
+
+    Folosita EXCLUSIV pentru dual-lookup la already_sent pe DB cu randuri vechi
+    (dinainte de T9). Nu folosi pentru randuri noi.
     """
     canonic = {
         "account_id": account_id,
@@ -31,9 +126,6 @@ def idempotency_key(account_id: int | None, prezentare: dict[str, Any]) -> str:
         "nr_inmatriculare": (prezentare.get("nr_inmatriculare") or "").strip().upper(),
         "data_prestatie": prezentare.get("data_prestatie"),
         "odometru_final": str(prezentare.get("odometru_final") or "").strip(),
-        # Identitatea operatiei = codul RAR daca exista, altfel codul intern ROAAUTO
-        # (hibrid): doua trimiteri ale aceleiasi comenzi dedup corect indiferent de
-        # forma in care vin codurile.
         "prestatii": sorted(_op_identity(p) for p in (prezentare.get("prestatii") or [])),
     }
     blob = json.dumps(canonic, sort_keys=True, ensure_ascii=False, separators=(",", ":"))
diff --git a/tests/test_canonicalize.py b/tests/test_canonicalize.py
new file mode 100644
index 0000000..a4c48d7
--- /dev/null
+++ b/tests/test_canonicalize.py
@@ -0,0 +1,186 @@
+"""Teste T9: canonicalize_row + build_key partajat (idempotency).
+
+Verify:
+(a) cross-canal: build_key(API canal-None) == build_key(import canal-rezolvat) pentru
+    acelasi rand logic.
+(b) regresie: strategia cheilor vechi (dual-lookup legacy) acoperita de test.
+(c) canonicalize taie ".0" din odometru inainte de validare.
+"""
+
+from __future__ import annotations
+
+import os
+import tempfile
+
+import pytest
+
+from app.idempotency import (
+    build_key,
+    build_key_legacy,
+    canonicalize_row,
+    idempotency_key,
+)
+
+
+# --- canonicalize_row ---
+
+def test_canonicalize_vin_upper():
+    raw = {"vin": "wvwzzz1kzaw000123", "nr_inmatriculare": "b999tst",
+           "data_prestatie": "2026-06-15", "odometru_final": "123456"}
+    c = canonicalize_row(raw)
+    assert c["vin"] == "WVWZZZ1KZAW000123"
+    assert c["nr_inmatriculare"] == "B999TST"
+
+
+def test_canonicalize_odometru_strip_dot_zero():
+    """123456.0 (Excel float) -> '123456'."""
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "2026-01-01",
+           "odometru_final": "123456.0"}
+    c = canonicalize_row(raw)
+    assert c["odometru_final"] == "123456"
+
+
+def test_canonicalize_odometru_numeric_float():
+    """Numeric float 123456.0 -> '123456'."""
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "2026-01-01",
+           "odometru_final": 123456.0}
+    c = canonicalize_row(raw)
+    assert c["odometru_final"] == "123456"
+
+
+def test_canonicalize_odometru_int_unchanged():
+    """Integer 123456 -> '123456' (nu e alterat)."""
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "2026-01-01",
+           "odometru_final": 123456}
+    c = canonicalize_row(raw)
+    assert c["odometru_final"] == "123456"
+
+
+def test_canonicalize_odometru_50_unchanged():
+    """'123456.50' nu e coercion pur — nu se taie."""
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "2026-01-01",
+           "odometru_final": "123456.50"}
+    c = canonicalize_row(raw)
+    assert c["odometru_final"] == "123456.50"
+
+
+def test_canonicalize_odometru_none():
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "2026-01-01"}
+    c = canonicalize_row(raw)
+    assert c["odometru_final"] == ""
+
+
+def test_canonicalize_data_strip():
+    raw = {"vin": "X", "nr_inmatriculare": "Y", "data_prestatie": "  2026-06-15  ",
+           "odometru_final": "1"}
+    c = canonicalize_row(raw)
+    assert c["data_prestatie"] == "2026-06-15"
+
+
+# --- build_key cross-canal (a) ---
+
+_RAND = {
+    "vin": "WVWZZZ1KZAW000123",
+    "nr_inmatriculare": "B999TST",
+    "data_prestatie": "2026-06-15",
+    "odometru_final": "123456",
+    "prestatii": [{"cod_prestatie": "OE-1"}],
+}
+
+
+def test_cross_canal_none_equals_1():
+    """(a) build_key cu account_id=None si account_id=1 dau aceeasi cheie."""
+    canon = canonicalize_row(_RAND)
+    k_none = build_key(None, canon)
+    k_1 = build_key(1, canon)
+    assert k_none == k_1, "cross-canal divergenta: None vs 1"
+
+
+def test_cross_canal_odometru_float():
+    """Odometru float din Excel: cheia e identica indiferent de canal."""
+    rand_float = {**_RAND, "odometru_final": "123456.0"}
+    rand_int = {**_RAND, "odometru_final": "123456"}
+    k_float_api = build_key(None, canonicalize_row(rand_float))
+    k_int_import = build_key(1, canonicalize_row(rand_int))
+    assert k_float_api == k_int_import, "float vs int odometru -> chei diferite"
+
+
+# --- idempotency_key wrapper ---
+
+def test_idempotency_key_backward_compat():
+    """idempotency_key(None, raw) produce aceeasi cheie ca build_key(None, canon)."""
+    canon = canonicalize_row(_RAND)
+    k_new = build_key(None, canon)
+    k_old = idempotency_key(None, _RAND)
+    assert k_new == k_old
+
+
+# --- build_key_legacy (b) ---
+
+def test_legacy_key_differs_from_new():
+    """(b) Cheia legacy (account_id=None in hash) difera de cheia noua (account_id=1)."""
+    canon = canonicalize_row(_RAND)
+    k_new = build_key(None, canon)  # None -> 1 in hash
+    k_legacy = build_key_legacy(None, _RAND)  # None AS-PASSED in hash
+    assert k_new != k_legacy, "legacy si new trebuie sa difere (diferit account_id in hash)"
+
+
+def test_legacy_dual_lookup_strategy():
+    """Strategia dual-lookup: row-uri vechi (cheie-None) gasite via build_key_legacy."""
+    # Simuleaza un rand cu cheie veche (account_id=None in hash)
+    old_key = build_key_legacy(None, _RAND)
+    # Noul build_key (None->1) NU gaseste randul direct
+    new_key = build_key(None, canonicalize_row(_RAND))
+    assert new_key != old_key
+    # Dual-lookup: incearca noul, apoi legacy
+    found = old_key in {old_key} or new_key in {old_key}
+    assert found, "dual-lookup trebuie sa gaseasca randul vechi"
+
+
+# --- Integrare: API route foloseste build_key (OV-2) ---
+
+@pytest.fixture()
+def client(monkeypatch):
+    tmp = tempfile.mkdtemp()
+    monkeypatch.setenv("AUTOPASS_DB_PATH", os.path.join(tmp, "t9.db"))
+    from app.config import get_settings
+    get_settings.cache_clear()
+    from app.main import app
+    from fastapi.testclient import TestClient
+    with TestClient(app) as c:
+        yield c
+    get_settings.cache_clear()
+
+
+def _body(**over):
+    prez = {
+        "vin": "WVWZZZ1KZAW000123",
+        "nr_inmatriculare": "B999TST",
+        "data_prestatie": "2026-06-15",
+        "odometru_final": "123456",
+        "prestatii": [{"cod_prestatie": "OE-1"}],
+    }
+    prez.update(over)
+    return {"rar_credentials": {"email": "x@y.ro", "password": "s"}, "prezentari": [prez]}
+
+
+def test_api_dedup_dupa_t9(client):
+    """Deduplicarea functioneaza dupa T9: acelasi rand -> acelasi submission."""
+    r1 = client.post("/v1/prezentari", json=_body())
+    r2 = client.post("/v1/prezentari", json=_body())
+    assert r1.status_code == 200
+    sid1 = r1.json()["results"][0]["submission_id"]
+    res2 = r2.json()["results"][0]
+    assert res2["submission_id"] == sid1
+    assert res2["deduped"] is True
+
+
+def test_api_odometru_float_dedup(client):
+    """Odometru float '123456.0' si '123456' dedup corect dupa canonicalizare."""
+    r1 = client.post("/v1/prezentari", json=_body(odometru_final="123456"))
+    r2 = client.post("/v1/prezentari", json=_body(odometru_final="123456.0"))
+    assert r1.status_code == 200
+    sid1 = r1.json()["results"][0]["submission_id"]
+    res2 = r2.json()["results"][0]
+    assert res2["submission_id"] == sid1, "odometru float si int trebuie sa dea acelasi submission"
+    assert res2["deduped"] is True