diff --git a/apps/api/src/services/sat/sat.service.ts b/apps/api/src/services/sat/sat.service.ts
new file mode 100644
index 0000000..7c41e3e
--- /dev/null
+++ b/apps/api/src/services/sat/sat.service.ts
@@ -0,0 +1,618 @@
+import { prisma } from '../../config/database.js';
+import { getDecryptedFiel } from '../fiel.service.js';
+import { authenticate, isTokenValid } from './sat-auth.service.js';
+import {
+  requestDownload,
+  verifyRequest,
+  downloadPackage,
+  isRequestComplete,
+  isRequestFailed,
+  isRequestInProgress,
+  SAT_REQUEST_STATES,
+} from './sat-download.service.js';
+import { processPackage, type CfdiParsed } from './sat-parser.service.js';
+import type { SatSyncJob, CfdiSyncType, SatSyncType } from '@horux/shared';
+import type { Credential } from '@nodecfdi/credentials/node';
+
+const POLL_INTERVAL_MS = 30000; // 30 segundos
+const MAX_POLL_ATTEMPTS = 60; // 30 minutos máximo
+const YEARS_TO_SYNC = 10;
+
+interface SyncContext {
+  credential: Credential;
+  token: string;
+  tokenExpiresAt: Date;
+  rfc: string;
+  tenantId: string;
+  schemaName: string;
+}
+
+/**
+ * Obtiene o renueva el token de autenticación
+ */
+async function ensureValidToken(ctx: SyncContext): Promise<void> {
+  if (!isTokenValid({ token: ctx.token, expiresAt: ctx.tokenExpiresAt })) {
+    console.log('[SAT] Renovando token...');
+    const newToken = await authenticate(ctx.credential);
+    ctx.token = newToken.token;
+    ctx.tokenExpiresAt = newToken.expiresAt;
+  }
+}
+
+/**
+ * Actualiza el progreso de un job
+ */
+async function updateJobProgress(
+  jobId: string,
+  updates: Partial<{
+    status: 'pending' | 'running' | 'completed' | 'failed';
+    satRequestId: string;
+    satPackageIds: string[];
+    cfdisFound: number;
+    cfdisDownloaded: number;
+    cfdisInserted: number;
+    cfdisUpdated: number;
+    progressPercent: number;
+    errorMessage: string;
+    startedAt: Date;
+    completedAt: Date;
+    retryCount: number;
+    nextRetryAt: Date;
+  }>
+): Promise<void> {
+  await prisma.satSyncJob.update({
+    where: { id: jobId },
+    data: updates,
+  });
+}
+
+/**
+ * Guarda los CFDIs en la base de datos del tenant
+ */
+async function saveCfdis(
+  schemaName: string,
+  cfdis: CfdiParsed[],
+  jobId: string
+): Promise<{ inserted: number; updated: number }> {
+  let inserted = 0;
+  let updated = 0;
+
+  for (const cfdi of cfdis) {
+    try {
+      // Usar raw query para el esquema del tenant
+      const existing = await prisma.$queryRawUnsafe<{ id: string }[]>(
+        `SELECT id FROM "${schemaName}".cfdis WHERE uuid_fiscal = $1`,
+        cfdi.uuidFiscal
+      );
+
+      if (existing.length > 0) {
+        // Actualizar CFDI existente
+        await prisma.$executeRawUnsafe(
+          `UPDATE "${schemaName}".cfdis SET
+            tipo = $2,
+            serie = $3,
+            folio = $4,
+            fecha_emision = $5,
+            fecha_timbrado = $6,
+            rfc_emisor = $7,
+            nombre_emisor = $8,
+            rfc_receptor = $9,
+            nombre_receptor = $10,
+            subtotal = $11,
+            descuento = $12,
+            iva = $13,
+            isr_retenido = $14,
+            iva_retenido = $15,
+            total = $16,
+            moneda = $17,
+            tipo_cambio = $18,
+            metodo_pago = $19,
+            forma_pago = $20,
+            uso_cfdi = $21,
+            estado = $22,
+            xml_original = $23,
+            last_sat_sync = NOW(),
+            sat_sync_job_id = $24,
+            updated_at = NOW()
+          WHERE uuid_fiscal = $1`,
+          cfdi.uuidFiscal,
+          cfdi.tipo,
+          cfdi.serie,
+          cfdi.folio,
+          cfdi.fechaEmision,
+          cfdi.fechaTimbrado,
+          cfdi.rfcEmisor,
+          cfdi.nombreEmisor,
+          cfdi.rfcReceptor,
+          cfdi.nombreReceptor,
+          cfdi.subtotal,
+          cfdi.descuento,
+          cfdi.iva,
+          cfdi.isrRetenido,
+          cfdi.ivaRetenido,
+          cfdi.total,
+          cfdi.moneda,
+          cfdi.tipoCambio,
+          cfdi.metodoPago,
+          cfdi.formaPago,
+          cfdi.usoCfdi,
+          cfdi.estado,
+          cfdi.xmlOriginal,
+          jobId
+        );
+        updated++;
+      } else {
+        // Insertar nuevo CFDI
+        await prisma.$executeRawUnsafe(
+          `INSERT INTO "${schemaName}".cfdis (
+            id, uuid_fiscal, tipo, serie, folio, fecha_emision, fecha_timbrado,
+            rfc_emisor, nombre_emisor, rfc_receptor, nombre_receptor,
+            subtotal, descuento, iva, isr_retenido, iva_retenido, total,
+            moneda, tipo_cambio, metodo_pago, forma_pago, uso_cfdi, estado,
+            xml_original, source, sat_sync_job_id, last_sat_sync, created_at
+          ) VALUES (
+            gen_random_uuid(), $1, $2, $3, $4, $5, $6, $7, $8, $9, $10,
+            $11, $12, $13, $14, $15, $16, $17, $18, $19, $20, $21, $22,
+            $23, 'sat', $24, NOW(), NOW()
+          )`,
+          cfdi.uuidFiscal,
+          cfdi.tipo,
+          cfdi.serie,
+          cfdi.folio,
+          cfdi.fechaEmision,
+          cfdi.fechaTimbrado,
+          cfdi.rfcEmisor,
+          cfdi.nombreEmisor,
+          cfdi.rfcReceptor,
+          cfdi.nombreReceptor,
+          cfdi.subtotal,
+          cfdi.descuento,
+          cfdi.iva,
+          cfdi.isrRetenido,
+          cfdi.ivaRetenido,
+          cfdi.total,
+          cfdi.moneda,
+          cfdi.tipoCambio,
+          cfdi.metodoPago,
+          cfdi.formaPago,
+          cfdi.usoCfdi,
+          cfdi.estado,
+          cfdi.xmlOriginal,
+          jobId
+        );
+        inserted++;
+      }
+    } catch (error) {
+      console.error(`[SAT] Error guardando CFDI ${cfdi.uuidFiscal}:`, error);
+    }
+  }
+
+  return { inserted, updated };
+}
+
+/**
+ * Procesa una solicitud de descarga para un rango de fechas
+ */
+async function processDateRange(
+  ctx: SyncContext,
+  jobId: string,
+  fechaInicio: Date,
+  fechaFin: Date,
+  tipoCfdi: CfdiSyncType
+): Promise<{ found: number; downloaded: number; inserted: number; updated: number }> {
+  console.log(`[SAT] Procesando ${tipoCfdi} desde ${fechaInicio.toISOString()} hasta ${fechaFin.toISOString()}`);
+
+  await ensureValidToken(ctx);
+
+  // 1. Solicitar descarga
+  const requestResponse = await requestDownload({
+    credential: ctx.credential,
+    token: ctx.token,
+    rfc: ctx.rfc,
+    fechaInicio,
+    fechaFin,
+    tipoSolicitud: 'CFDI',
+    tipoCfdi,
+  });
+
+  if (requestResponse.codEstatus !== '5000') {
+    if (requestResponse.codEstatus === '5004') {
+      console.log('[SAT] No se encontraron CFDIs en el rango');
+      return { found: 0, downloaded: 0, inserted: 0, updated: 0 };
+    }
+    throw new Error(`Error SAT: ${requestResponse.codEstatus} - ${requestResponse.mensaje}`);
+  }
+
+  const idSolicitud = requestResponse.idSolicitud;
+  console.log(`[SAT] Solicitud creada: ${idSolicitud}`);
+
+  await updateJobProgress(jobId, { satRequestId: idSolicitud });
+
+  // 2. Esperar y verificar solicitud
+  let verifyResponse;
+  let attempts = 0;
+
+  while (attempts < MAX_POLL_ATTEMPTS) {
+    await new Promise(resolve => setTimeout(resolve, POLL_INTERVAL_MS));
+    attempts++;
+
+    await ensureValidToken(ctx);
+    verifyResponse = await verifyRequest(ctx.credential, ctx.token, ctx.rfc, idSolicitud);
+
+    console.log(`[SAT] Estado solicitud: ${verifyResponse.estadoSolicitud} (intento ${attempts})`);
+
+    if (isRequestComplete(verifyResponse.estadoSolicitud)) {
+      break;
+    }
+
+    if (isRequestFailed(verifyResponse.estadoSolicitud)) {
+      throw new Error(`Solicitud fallida: ${verifyResponse.mensaje}`);
+    }
+  }
+
+  if (!verifyResponse || !isRequestComplete(verifyResponse.estadoSolicitud)) {
+    throw new Error('Timeout esperando respuesta del SAT');
+  }
+
+  // 3. Descargar paquetes
+  const packageIds = verifyResponse.paquetes;
+  await updateJobProgress(jobId, {
+    satPackageIds: packageIds,
+    cfdisFound: verifyResponse.numeroCfdis,
+  });
+
+  let totalInserted = 0;
+  let totalUpdated = 0;
+  let totalDownloaded = 0;
+
+  for (let i = 0; i < packageIds.length; i++) {
+    const packageId = packageIds[i];
+    console.log(`[SAT] Descargando paquete ${i + 1}/${packageIds.length}: ${packageId}`);
+
+    await ensureValidToken(ctx);
+    const packageResponse = await downloadPackage(ctx.credential, ctx.token, ctx.rfc, packageId);
+
+    // 4. Procesar paquete
+    const cfdis = processPackage(packageResponse.paquete);
+    totalDownloaded += cfdis.length;
+
+    console.log(`[SAT] Procesando ${cfdis.length} CFDIs del paquete`);
+
+    const { inserted, updated } = await saveCfdis(ctx.schemaName, cfdis, jobId);
+    totalInserted += inserted;
+    totalUpdated += updated;
+
+    // Actualizar progreso
+    const progress = Math.round(((i + 1) / packageIds.length) * 100);
+    await updateJobProgress(jobId, {
+      cfdisDownloaded: totalDownloaded,
+      cfdisInserted: totalInserted,
+      cfdisUpdated: totalUpdated,
+      progressPercent: progress,
+    });
+  }
+
+  return {
+    found: verifyResponse.numeroCfdis,
+    downloaded: totalDownloaded,
+    inserted: totalInserted,
+    updated: totalUpdated,
+  };
+}
+
+/**
+ * Ejecuta sincronización inicial (últimos 10 años)
+ */
+async function processInitialSync(ctx: SyncContext, jobId: string): Promise<void> {
+  const ahora = new Date();
+  const inicioHistorico = new Date(ahora.getFullYear() - YEARS_TO_SYNC, ahora.getMonth(), 1);
+
+  let totalFound = 0;
+  let totalDownloaded = 0;
+  let totalInserted = 0;
+  let totalUpdated = 0;
+
+  // Procesar por meses para evitar límites del SAT
+  let currentDate = new Date(inicioHistorico);
+
+  while (currentDate < ahora) {
+    const monthEnd = new Date(currentDate.getFullYear(), currentDate.getMonth() + 1, 0, 23, 59, 59);
+    const rangeEnd = monthEnd > ahora ? ahora : monthEnd;
+
+    // Procesar emitidos
+    try {
+      const emitidos = await processDateRange(ctx, jobId, currentDate, rangeEnd, 'emitidos');
+      totalFound += emitidos.found;
+      totalDownloaded += emitidos.downloaded;
+      totalInserted += emitidos.inserted;
+      totalUpdated += emitidos.updated;
+    } catch (error: any) {
+      console.error(`[SAT] Error procesando emitidos ${currentDate.toISOString()}:`, error.message);
+    }
+
+    // Procesar recibidos
+    try {
+      const recibidos = await processDateRange(ctx, jobId, currentDate, rangeEnd, 'recibidos');
+      totalFound += recibidos.found;
+      totalDownloaded += recibidos.downloaded;
+      totalInserted += recibidos.inserted;
+      totalUpdated += recibidos.updated;
+    } catch (error: any) {
+      console.error(`[SAT] Error procesando recibidos ${currentDate.toISOString()}:`, error.message);
+    }
+
+    // Siguiente mes
+    currentDate = new Date(currentDate.getFullYear(), currentDate.getMonth() + 1, 1);
+
+    // Pequeña pausa entre meses para no saturar el SAT
+    await new Promise(resolve => setTimeout(resolve, 5000));
+  }
+
+  await updateJobProgress(jobId, {
+    cfdisFound: totalFound,
+    cfdisDownloaded: totalDownloaded,
+    cfdisInserted: totalInserted,
+    cfdisUpdated: totalUpdated,
+  });
+}
+
+/**
+ * Ejecuta sincronización diaria (mes actual)
+ */
+async function processDailySync(ctx: SyncContext, jobId: string): Promise<void> {
+  const ahora = new Date();
+  const inicioMes = new Date(ahora.getFullYear(), ahora.getMonth(), 1);
+
+  let totalFound = 0;
+  let totalDownloaded = 0;
+  let totalInserted = 0;
+  let totalUpdated = 0;
+
+  // Procesar emitidos del mes
+  try {
+    const emitidos = await processDateRange(ctx, jobId, inicioMes, ahora, 'emitidos');
+    totalFound += emitidos.found;
+    totalDownloaded += emitidos.downloaded;
+    totalInserted += emitidos.inserted;
+    totalUpdated += emitidos.updated;
+  } catch (error: any) {
+    console.error('[SAT] Error procesando emitidos:', error.message);
+  }
+
+  // Procesar recibidos del mes
+  try {
+    const recibidos = await processDateRange(ctx, jobId, inicioMes, ahora, 'recibidos');
+    totalFound += recibidos.found;
+    totalDownloaded += recibidos.downloaded;
+    totalInserted += recibidos.inserted;
+    totalUpdated += recibidos.updated;
+  } catch (error: any) {
+    console.error('[SAT] Error procesando recibidos:', error.message);
+  }
+
+  await updateJobProgress(jobId, {
+    cfdisFound: totalFound,
+    cfdisDownloaded: totalDownloaded,
+    cfdisInserted: totalInserted,
+    cfdisUpdated: totalUpdated,
+  });
+}
+
+/**
+ * Inicia la sincronización con el SAT
+ */
+export async function startSync(
+  tenantId: string,
+  type: SatSyncType = 'daily',
+  dateFrom?: Date,
+  dateTo?: Date
+): Promise<string> {
+  // Obtener credenciales FIEL
+  const fielData = await getDecryptedFiel(tenantId);
+  if (!fielData) {
+    throw new Error('No hay FIEL configurada o está vencida');
+  }
+
+  // Obtener datos del tenant
+  const tenant = await prisma.tenant.findUnique({
+    where: { id: tenantId },
+    select: { schemaName: true },
+  });
+
+  if (!tenant) {
+    throw new Error('Tenant no encontrado');
+  }
+
+  // Verificar que no haya sync activo
+  const activeSync = await prisma.satSyncJob.findFirst({
+    where: {
+      tenantId,
+      status: { in: ['pending', 'running'] },
+    },
+  });
+
+  if (activeSync) {
+    throw new Error('Ya hay una sincronización en curso');
+  }
+
+  // Crear job
+  const now = new Date();
+  const job = await prisma.satSyncJob.create({
+    data: {
+      tenantId,
+      type,
+      status: 'running',
+      dateFrom: dateFrom || new Date(now.getFullYear() - YEARS_TO_SYNC, 0, 1),
+      dateTo: dateTo || now,
+      startedAt: now,
+    },
+  });
+
+  // Autenticar con SAT
+  const tokenData = await authenticate(fielData.credential);
+
+  const ctx: SyncContext = {
+    credential: fielData.credential,
+    token: tokenData.token,
+    tokenExpiresAt: tokenData.expiresAt,
+    rfc: fielData.rfc,
+    tenantId,
+    schemaName: tenant.schemaName,
+  };
+
+  // Ejecutar sincronización en background
+  (async () => {
+    try {
+      if (type === 'initial') {
+        await processInitialSync(ctx, job.id);
+      } else {
+        await processDailySync(ctx, job.id);
+      }
+
+      await updateJobProgress(job.id, {
+        status: 'completed',
+        completedAt: new Date(),
+        progressPercent: 100,
+      });
+
+      console.log(`[SAT] Sincronización ${job.id} completada`);
+    } catch (error: any) {
+      console.error(`[SAT] Error en sincronización ${job.id}:`, error);
+      await updateJobProgress(job.id, {
+        status: 'failed',
+        errorMessage: error.message,
+        completedAt: new Date(),
+      });
+    }
+  })();
+
+  return job.id;
+}
+
+/**
+ * Obtiene el estado actual de sincronización de un tenant
+ */
+export async function getSyncStatus(tenantId: string): Promise<{
+  hasActiveSync: boolean;
+  currentJob?: SatSyncJob;
+  lastCompletedJob?: SatSyncJob;
+  totalCfdisSynced: number;
+}> {
+  const activeJob = await prisma.satSyncJob.findFirst({
+    where: {
+      tenantId,
+      status: { in: ['pending', 'running'] },
+    },
+    orderBy: { createdAt: 'desc' },
+  });
+
+  const lastCompleted = await prisma.satSyncJob.findFirst({
+    where: {
+      tenantId,
+      status: 'completed',
+    },
+    orderBy: { completedAt: 'desc' },
+  });
+
+  const totals = await prisma.satSyncJob.aggregate({
+    where: {
+      tenantId,
+      status: 'completed',
+    },
+    _sum: {
+      cfdisInserted: true,
+    },
+  });
+
+  const mapJob = (job: any): SatSyncJob => ({
+    id: job.id,
+    tenantId: job.tenantId,
+    type: job.type,
+    status: job.status,
+    dateFrom: job.dateFrom.toISOString(),
+    dateTo: job.dateTo.toISOString(),
+    cfdiType: job.cfdiType ?? undefined,
+    satRequestId: job.satRequestId ?? undefined,
+    satPackageIds: job.satPackageIds,
+    cfdisFound: job.cfdisFound,
+    cfdisDownloaded: job.cfdisDownloaded,
+    cfdisInserted: job.cfdisInserted,
+    cfdisUpdated: job.cfdisUpdated,
+    progressPercent: job.progressPercent,
+    errorMessage: job.errorMessage ?? undefined,
+    startedAt: job.startedAt?.toISOString(),
+    completedAt: job.completedAt?.toISOString(),
+    createdAt: job.createdAt.toISOString(),
+    retryCount: job.retryCount,
+  });
+
+  return {
+    hasActiveSync: !!activeJob,
+    currentJob: activeJob ? mapJob(activeJob) : undefined,
+    lastCompletedJob: lastCompleted ? mapJob(lastCompleted) : undefined,
+    totalCfdisSynced: totals._sum.cfdisInserted || 0,
+  };
+}
+
+/**
+ * Obtiene el historial de sincronizaciones
+ */
+export async function getSyncHistory(
+  tenantId: string,
+  page: number = 1,
+  limit: number = 10
+): Promise<{ jobs: SatSyncJob[]; total: number }> {
+  const [jobs, total] = await Promise.all([
+    prisma.satSyncJob.findMany({
+      where: { tenantId },
+      orderBy: { createdAt: 'desc' },
+      skip: (page - 1) * limit,
+      take: limit,
+    }),
+    prisma.satSyncJob.count({ where: { tenantId } }),
+  ]);
+
+  return {
+    jobs: jobs.map(job => ({
+      id: job.id,
+      tenantId: job.tenantId,
+      type: job.type,
+      status: job.status,
+      dateFrom: job.dateFrom.toISOString(),
+      dateTo: job.dateTo.toISOString(),
+      cfdiType: job.cfdiType ?? undefined,
+      satRequestId: job.satRequestId ?? undefined,
+      satPackageIds: job.satPackageIds,
+      cfdisFound: job.cfdisFound,
+      cfdisDownloaded: job.cfdisDownloaded,
+      cfdisInserted: job.cfdisInserted,
+      cfdisUpdated: job.cfdisUpdated,
+      progressPercent: job.progressPercent,
+      errorMessage: job.errorMessage ?? undefined,
+      startedAt: job.startedAt?.toISOString(),
+      completedAt: job.completedAt?.toISOString(),
+      createdAt: job.createdAt.toISOString(),
+      retryCount: job.retryCount,
+    })),
+    total,
+  };
+}
+
+/**
+ * Reintenta un job fallido
+ */
+export async function retryJob(jobId: string): Promise<string> {
+  const job = await prisma.satSyncJob.findUnique({
+    where: { id: jobId },
+  });
+
+  if (!job) {
+    throw new Error('Job no encontrado');
+  }
+
+  if (job.status !== 'failed') {
+    throw new Error('Solo se pueden reintentar jobs fallidos');
+  }
+
+  return startSync(job.tenantId, job.type, job.dateFrom, job.dateTo);
+}