diff --git a/SINGLE_EVALUATION_FLOW.md b/SINGLE_EVALUATION_FLOW.md
new file mode 100644
index 0000000..c00bfc0
--- /dev/null
+++ b/SINGLE_EVALUATION_FLOW.md
@@ -0,0 +1,132 @@
+# SINGLE_EVALUATION_FLOW
+
+## Scopo
+Descrive il flusso frontend della funzionalità **Evaluación Individual** (route: `/evaluations/single`) e il passaggio alla pagina risultati **FastCheck** (route: `/fast-check-ex`), includendo le chiamate API effettuate dal frontend.
+
+## Componenti coinvolti
+- **UI form valutazione**: `src/pages/evaluations/SingleEvaluation.tsx`
+- **Pagina risultati**: `src/pages/FastCheckEX.tsx`
+- **Client HTTP**: `src/services/api.ts` (`apiClient`)
+- **Auth**: `src/contexts/AuthContext.tsx` + `src/services/authService.ts`
+- **Tenant/Crediti**: `src/contexts/TenantContext.tsx`
+
+## Base URL API
+Il frontend usa:
+- `globalThis.__APP_ENV__?.VITE_API_BASE_URL`
+- fallback: `https://duxiter.azurianlab.com/api`
+
+Tutte le chiamate sotto sono relative a questa base URL.
+
+## Flusso ad alto livello
+1. L’utente apre **Evaluación Individual** (`/evaluations/single`)
+2. Il frontend carica contesto sessione/tenant (token + crediti)
+3. L’utente inserisce e conferma il **RUT** (validazione lato client + accettazione termini)
+4. Alla submit:
+   - controlla se esiste già un risultato in DB
+   - se esiste: reindirizza direttamente a **FastCheck** con `rut` in querystring
+   - se non esiste: avvia `lookup` e poi reindirizza a **FastCheck**
+5. In **FastCheck** vengono caricati i dettagli del risultato e i dati “accessori” (AI analysis, liste, note, ecc.)
+
+## Normalizzazione RUT (frontend)
+- Durante digitazione il RUT viene formattato.
+- Prima delle API, il RUT viene “sanitizzato” togliendo i punti: `formattedRut.replace(/\./g, '')`
+- L’hyphen rimane (es. `12.345.678-9` → `12345678-9`)
+
+## Diagramma (sequenza)
+
+```mermaid
+sequenceDiagram
+  autonumber
+  actor U as Utente
+  participant SE as FE: /evaluations/single (SingleEvaluation.tsx)
+  participant AC as FE: AuthContext/AuthService
+  participant TC as FE: TenantContext
+  participant API as Backend API (VITE_API_BASE_URL)
+  participant FC as FE: /fast-check-ex (FastCheckEX.tsx)
+
+  U->>SE: Apre pagina
+  SE->>AC: Ripristina sessione (token in localStorage)
+  AC->>API: GET /auth/me
+  SE->>TC: Carica tenant/crediti
+  TC->>API: GET /tenant (Bearer token)
+
+  U->>SE: Inserisce RUT + accetta termini
+  U->>SE: Submit
+
+  SE->>API: GET /rut/results/rut/{rutSanitized}
+  alt Esiste già un risultato
+    SE-->>FC: navigate("/fast-check-ex?rut={rutSanitized}")
+  else Non esiste (404)
+    SE->>API: POST /rut/lookup { rut: rutSanitized, isMonitoring: false }
+    SE-->>FC: navigate("/fast-check-ex?rut={rutSanitized}")
+  end
+
+  FC->>API: GET /rut/results/rut/{rutSanitized} (opzionale ?risk=true)
+  opt Se non c'è rut o serve "latest"
+    FC->>API: GET /rut/results/latest
+    FC->>API: GET /rut/results/rut/{latestRut}
+  end
+  opt Funzioni accessorie in FastCheck
+    FC->>API: GET /rut/ai-analysis/{rut} (opzionale ?regenerate=true)
+    FC->>API: POST /rut/fast-check-summary/{rut} { summary }
+    FC->>API: GET /lpalto/search/rut/{rut}
+    FC->>API: GET /lpmedio/search/rut/{rut}
+    FC->>API: GET /antiunion-cases/rut/{rut}
+    FC->>API: GET /user-notes/rut/{rut}
+    FC->>API: POST /user-notes { rut, note, tags }
+    FC->>API: PUT /user-notes/{noteId} { note, tags }
+    FC->>API: DELETE /user-notes/{noteId}
+    FC->>API: PUT /rut/results/rut/{rut}/update-pep-status { ... }
+  end
+```
+
+## Chiamate API per “Evaluación Individual” (pagina `/evaluations/single`)
+Chiamate direttamente collegate al submit:
+
+1. **Controllo esistenza risultato**
+- `GET /rut/results/rut/{rut}`
+  - Se risponde con dati: considerato “già esistente” → redirect a FastCheck
+  - Se 404: procede con `lookup`
+
+2. **Avvio valutazione**
+- `POST /rut/lookup`
+  - Body: `{ "rut": "{rut}", "isMonitoring": false }`
+  - In seguito redirect a FastCheck
+
+## Chiamate “di contesto” (sessione/tenant)
+Queste possono avvenire mentre l’utente è su `/evaluations/single`:
+
+- `GET /auth/me` (ripristino sessione)
+- `GET /tenant` (crediti/tenant; header `Authorization: Bearer <token>`)
+
+## Caricamento risultati (pagina `/fast-check-ex`)
+FastCheck usa tipicamente questi endpoint per mostrare il risultato della valutazione:
+
+- `GET /rut/results/rut/{rut}` (opzionale `?risk=true`)
+- `GET /rut/results/{resultId}` (opzionale `?risk=true`)
+- `GET /rut/results/latest`
+
+In base alle feature attive in UI, possono aggiungersi:
+- `GET /rut/ai-analysis/{rut}` (opzionale `?regenerate=true`)
+- `POST /rut/fast-check-summary/{rut}`
+- `GET /lpalto/search/rut/{rut}`
+- `GET /lpmedio/search/rut/{rut}`
+- `GET /antiunion-cases/rut/{rut}`
+- Note utente:
+  - `GET /user-notes/rut/{rut}`
+  - `POST /user-notes`
+  - `PUT /user-notes/{noteId}`
+  - `DELETE /user-notes/{noteId}`
+- Aggiornamento stato PEP:
+  - `PUT /rut/results/rut/{rut}/update-pep-status`
+
+## Stati e UX (sintesi)
+- Submit bloccato se:
+  - RUT non valido
+  - termini non accettati
+  - loading in corso
+- Se crediti tenant = 0: viene mostrato un dialog informativo.
+- In caso di errore non-404 nel check esistenza: viene loggato ma il flusso continua con `lookup`.
+
+## Note operative
+- Il redirect a `/fast-check-ex` è parte integrante del flusso: la pagina “Evaluación Individual” funge da avvio/trigger, mentre la visualizzazione del risultato avviene in FastCheck.
diff --git a/fastcheck_api/app/api/v1/routers/rut.py b/fastcheck_api/app/api/v1/routers/rut.py
new file mode 100644
index 0000000..5bffa96
--- /dev/null
+++ b/fastcheck_api/app/api/v1/routers/rut.py
@@ -0,0 +1,219 @@
+from __future__ import annotations
+
+import datetime as dt
+import time
+from typing import Annotated, Any
+
+from fastapi import APIRouter, Depends, HTTPException, Request, status
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+from motor.motor_asyncio import AsyncIOMotorDatabase
+from pymongo import ReturnDocument
+from pydantic import BaseModel, Field
+
+from fastcheck_api.app.api.dependencies import CurrentUser, require_permission
+from fastcheck_api.app.core.mongodb import get_db
+from fastcheck_api.app.services.audit_service import AuditService
+from fastcheck_api.app.services.legacy_service import legacy_service
+from fastcheck_api.app.utils.mongo import sanitize_rut, to_object_id
+
+
+router = APIRouter(prefix="/rut", tags=["rut"])
+
+_bearer = HTTPBearer(auto_error=False)
+
+
+class RutLookupRequest(BaseModel):
+    rut: str = Field(examples=["12345678-9"])
+    isMonitoring: bool = Field(default=False, description="Compatibility flag with legacy backend.")
+
+
+@router.post(
+    "/lookup",
+    summary="Lookup RUT (single evaluation)",
+    description=(
+        "Runs a single evaluation for a RUT using the legacy backend and persists the result in MongoDB.\n\n"
+        "If a successful result for the same RUT already exists for the tenant, returns it without consuming credits."
+    ),
+)
+async def lookup_rut(
+    request: Request,
+    payload: RutLookupRequest,
+    user: Annotated[CurrentUser, Depends(require_permission("rut:lookup"))],
+    db: Annotated[AsyncIOMotorDatabase, Depends(get_db)],
+    credentials: Annotated[HTTPAuthorizationCredentials | None, Depends(_bearer)] = None,
+):
+    start = time.perf_counter()
+    rut = sanitize_rut(payload.rut)
+
+    token = credentials.credentials if credentials else None
+    if not token:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="No token provided")
+
+    cached = (
+        await db["evaluationresults"]
+        .find({"tenantId": user.tenant, "rut": rut, "status": "success"})
+        .sort([("createdAt", -1)])
+        .limit(1)
+        .to_list(length=1)
+    )
+    if cached and isinstance(cached[0], dict) and isinstance(cached[0].get("data"), dict):
+        await AuditService.log_consulta(
+            db=db,
+            tenant_id=user.tenant,
+            user_id=user.id,
+            consulta_type="individual",
+            rut=rut,
+            endpoint="/api/v1/rut/lookup",
+            response_status=status.HTTP_200_OK,
+            request_data={"rut": rut, "isMonitoring": payload.isMonitoring},
+            response_data={"source": "cache"},
+            processing_time_ms=int((time.perf_counter() - start) * 1000),
+            credits_used=0,
+            ip_address=request.client.host if request.client else None,
+            user_agent=request.headers.get("user-agent"),
+            metadata={"source": "cache"},
+        )
+        return {**cached[0]["data"], "isFromCache": True}
+
+    tenant_oid = to_object_id(user.tenant)
+    now = dt.datetime.now(dt.timezone.utc)
+
+    tenant_after = await db["tenants"].find_one_and_update(
+        {"_id": tenant_oid, "creditBalance.availableCredits": {"$gte": 1}},
+        {
+            "$inc": {
+                "creditBalance.availableCredits": -1,
+                "creditBalance.totalCreditsUsed": 1,
+            },
+            "$set": {
+                "creditBalance.lastCreditOperation": now,
+                "updatedAt": now,
+            },
+        },
+        return_document=ReturnDocument.AFTER,
+    )
+    if not tenant_after:
+        await AuditService.log_consulta(
+            db=db,
+            tenant_id=user.tenant,
+            user_id=user.id,
+            consulta_type="individual",
+            rut=rut,
+            endpoint="/api/v1/rut/lookup",
+            response_status=status.HTTP_402_PAYMENT_REQUIRED,
+            request_data={"rut": rut, "isMonitoring": payload.isMonitoring},
+            processing_time_ms=int((time.perf_counter() - start) * 1000),
+            credits_used=0,
+            ip_address=request.client.host if request.client else None,
+            user_agent=request.headers.get("user-agent"),
+            metadata={"reason": "insufficient_credits"},
+        )
+        raise HTTPException(status_code=status.HTTP_402_PAYMENT_REQUIRED, detail="Insufficient credits")
+
+    new_balance = int((tenant_after.get("creditBalance") or {}).get("availableCredits") or 0)
+    await db["creditoperations"].insert_one(
+        {
+            "tenantId": tenant_oid,
+            "userId": to_object_id(user.id),
+            "operationType": "evaluation",
+            "creditsChanged": -1,
+            "balanceAfter": new_balance,
+            "description": f"Valutazione singola per {rut}",
+            "metadata": {"evaluationType": "single", "supplierRut": rut},
+            "createdAt": now,
+        }
+    )
+
+    job_doc: dict[str, Any] = {
+        "tenantId": user.tenant,
+        "status": "processing",
+        "type": "single",
+        "createdBy": user.id,
+        "totalEvaluations": 1,
+        "completedEvaluations": 0,
+        "failedEvaluations": 0,
+        "supplierData": {"rut": rut, "name": "N/A"},
+        "createdAt": now,
+        "updatedAt": now,
+    }
+    job_insert = await db["evaluationjobs"].insert_one(job_doc)
+    job_id = str(job_insert.inserted_id)
+
+    response_status = status.HTTP_200_OK
+    error_message: str | None = None
+    result_data: dict[str, Any] | None = None
+    try:
+        result_data = await legacy_service.lookup_rut(
+            rut=rut,
+            token=token,
+            is_monitoring=payload.isMonitoring,
+            evaluation_type="individual",
+        )
+        ai_summary = result_data.get("aiAnalysis")
+        if isinstance(ai_summary, str) and ai_summary.strip():
+            try:
+                await legacy_service.save_fastcheck_summary(rut=rut, summary=ai_summary, token=token)
+            except Exception:
+                pass
+
+        await db["evaluationresults"].insert_one(
+            {
+                "jobId": job_insert.inserted_id,
+                "tenantId": user.tenant,
+                "rut": rut,
+                "name": None,
+                "status": "success",
+                "data": result_data,
+                "createdAt": now,
+                "updatedAt": now,
+            }
+        )
+        await db["evaluationjobs"].update_one(
+            {"_id": job_insert.inserted_id, "tenantId": user.tenant},
+            {"$set": {"status": "completed", "completedEvaluations": 1, "updatedAt": now}},
+        )
+        return {**result_data, "jobId": job_id, "isFromCache": False}
+    except HTTPException as e:
+        raise e
+    except Exception as e:
+        response_status = status.HTTP_502_BAD_GATEWAY
+        error_message = str(e)
+        await db["evaluationresults"].insert_one(
+            {
+                "jobId": job_insert.inserted_id,
+                "tenantId": user.tenant,
+                "rut": rut,
+                "name": None,
+                "status": "failed",
+                "error": error_message,
+                "createdAt": now,
+                "updatedAt": now,
+            }
+        )
+        await db["evaluationjobs"].update_one(
+            {"_id": job_insert.inserted_id, "tenantId": user.tenant},
+            {"$set": {"status": "completed", "failedEvaluations": 1, "updatedAt": now}},
+        )
+        raise HTTPException(status_code=response_status, detail="Legacy lookup failed")
+    finally:
+        processing_ms = int((time.perf_counter() - start) * 1000)
+        audit_response: dict[str, Any] | None = None
+        if result_data is not None:
+            audit_response = {"jobId": job_id}
+        await AuditService.log_consulta(
+            db=db,
+            tenant_id=user.tenant,
+            user_id=user.id,
+            consulta_type="individual",
+            rut=rut,
+            endpoint="/api/v1/rut/lookup",
+            response_status=response_status,
+            request_data={"rut": rut, "isMonitoring": payload.isMonitoring},
+            response_data=audit_response,
+            error_message=error_message,
+            processing_time_ms=processing_ms,
+            credits_used=1,
+            ip_address=request.client.host if request.client else None,
+            user_agent=request.headers.get("user-agent"),
+            metadata={"evaluationType": "single", "jobId": job_id},
+        )
diff --git a/fastcheck_api/app/main.py b/fastcheck_api/app/main.py
index 5f57af3..d2cef51 100644
--- a/fastcheck_api/app/main.py
+++ b/fastcheck_api/app/main.py
@@ -8,7 +8,7 @@ from fastapi import APIRouter
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import HTMLResponse, JSONResponse
 
-from fastcheck_api.app.api.v1.routers import auth, checks, reports, usage
+from fastcheck_api.app.api.v1.routers import auth, checks, reports, rut, usage
 from fastcheck_api.app.core.logging import configure_logging
 from fastcheck_api.app.core.mongodb import lifespan_db
 from fastcheck_api.app.services.legacy_service import legacy_service
@@ -24,6 +24,7 @@ tags_metadata = [
     {"name": "auth", "description": "Authentication and session management."},
     {"name": "checks", "description": "Create checks (evaluations) and retrieve job/results."},
     {"name": "reports", "description": "Fetch saved reports from existing persistence."},
+    {"name": "rut", "description": "Legacy-compatible RUT lookup endpoints."},
     {"name": "usage", "description": "Usage and credit balance information."},
 ]
 
@@ -156,5 +157,6 @@ async def prefixed_openapi():
 api_v1.include_router(auth.router)
 api_v1.include_router(checks.router)
 api_v1.include_router(reports.router)
+api_v1.include_router(rut.router)
 api_v1.include_router(usage.router)
 app.include_router(api_v1)
diff --git a/fastcheck_api/app/services/legacy_service.py b/fastcheck_api/app/services/legacy_service.py
index 3597c61..615bf81 100644
--- a/fastcheck_api/app/services/legacy_service.py
+++ b/fastcheck_api/app/services/legacy_service.py
@@ -17,11 +17,18 @@ class LegacyService:
     async def close(self) -> None:
         await self._client.aclose()
 
-    async def lookup_rut(self, *, rut: str, token: str) -> dict[str, Any]:
+    async def lookup_rut(
+        self,
+        *,
+        rut: str,
+        token: str,
+        is_monitoring: bool = False,
+        evaluation_type: str = "individual",
+    ) -> dict[str, Any]:
         resp = await self._client.post(
             "rut/lookup",
             headers={"Authorization": f"Bearer {token}"},
-            json={"rut": rut, "isMonitoring": False, "type": "masiva"},
+            json={"rut": rut, "isMonitoring": is_monitoring, "type": evaluation_type},
         )
         resp.raise_for_status()
         data = resp.json()