diff --git a/src/shared/services/base.service.ts b/src/shared/services/base.service.ts
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+++ b/src/shared/services/base.service.ts
@@ -0,0 +1,429 @@
+import { query, queryOne, getClient, PoolClient } from '../../config/database.js';
+import { NotFoundError, ValidationError } from '../errors/index.js';
+import { PaginationMeta } from '../types/index.js';
+
+/**
+ * Resultado paginado genérico
+ */
+export interface PaginatedResult<T> {
+  data: T[];
+  total: number;
+  page: number;
+  limit: number;
+  totalPages: number;
+}
+
+/**
+ * Filtros de paginación base
+ */
+export interface BasePaginationFilters {
+  page?: number;
+  limit?: number;
+  sortBy?: string;
+  sortOrder?: 'asc' | 'desc';
+  search?: string;
+}
+
+/**
+ * Opciones para construcción de queries
+ */
+export interface QueryOptions {
+  client?: PoolClient;
+  includeDeleted?: boolean;
+}
+
+/**
+ * Configuración del servicio base
+ */
+export interface BaseServiceConfig {
+  tableName: string;
+  schema: string;
+  selectFields: string;
+  searchFields?: string[];
+  defaultSortField?: string;
+  softDelete?: boolean;
+}
+
+/**
+ * Clase base abstracta para servicios CRUD con soporte multi-tenant
+ *
+ * Proporciona implementaciones reutilizables para:
+ * - Paginación con filtros
+ * - Búsqueda por texto
+ * - CRUD básico
+ * - Soft delete
+ * - Transacciones
+ *
+ * @example
+ * ```typescript
+ * class PartnersService extends BaseService<Partner, CreatePartnerDto, UpdatePartnerDto> {
+ *   protected config: BaseServiceConfig = {
+ *     tableName: 'partners',
+ *     schema: 'core',
+ *     selectFields: 'id, tenant_id, name, email, phone, created_at',
+ *     searchFields: ['name', 'email', 'tax_id'],
+ *     defaultSortField: 'name',
+ *     softDelete: true,
+ *   };
+ * }
+ * ```
+ */
+export abstract class BaseService<T, CreateDto, UpdateDto> {
+  protected abstract config: BaseServiceConfig;
+
+  /**
+   * Nombre completo de la tabla (schema.table)
+   */
+  protected get fullTableName(): string {
+    return `${this.config.schema}.${this.config.tableName}`;
+  }
+
+  /**
+   * Obtiene todos los registros con paginación y filtros
+   */
+  async findAll(
+    tenantId: string,
+    filters: BasePaginationFilters & Record<string, any> = {},
+    options: QueryOptions = {}
+  ): Promise<PaginatedResult<T>> {
+    const {
+      page = 1,
+      limit = 20,
+      sortBy = this.config.defaultSortField || 'created_at',
+      sortOrder = 'desc',
+      search,
+      ...customFilters
+    } = filters;
+
+    const offset = (page - 1) * limit;
+    const params: any[] = [tenantId];
+    let paramIndex = 2;
+
+    // Construir WHERE clause
+    let whereClause = 'WHERE tenant_id = $1';
+
+    // Soft delete
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
+
+    // Búsqueda por texto
+    if (search && this.config.searchFields?.length) {
+      const searchConditions = this.config.searchFields
+        .map(field => `${field} ILIKE $${paramIndex}`)
+        .join(' OR ');
+      whereClause += ` AND (${searchConditions})`;
+      params.push(`%${search}%`);
+      paramIndex++;
+    }
+
+    // Filtros custom
+    for (const [key, value] of Object.entries(customFilters)) {
+      if (value !== undefined && value !== null && value !== '') {
+        whereClause += ` AND ${key} = $${paramIndex++}`;
+        params.push(value);
+      }
+    }
+
+    // Validar sortBy para prevenir SQL injection
+    const safeSortBy = this.sanitizeFieldName(sortBy);
+    const safeSortOrder = sortOrder === 'asc' ? 'ASC' : 'DESC';
+
+    // Query de conteo
+    const countSql = `
+      SELECT COUNT(*) as count
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
+
+    // Query de datos
+    const dataSql = `
+      SELECT ${this.config.selectFields}
+      FROM ${this.fullTableName}
+      ${whereClause}
+      ORDER BY ${safeSortBy} ${safeSortOrder}
+      LIMIT $${paramIndex++} OFFSET $${paramIndex}
+    `;
+
+    if (options.client) {
+      const [countResult, dataResult] = await Promise.all([
+        options.client.query(countSql, params),
+        options.client.query(dataSql, [...params, limit, offset]),
+      ]);
+
+      const total = parseInt(countResult.rows[0]?.count || '0', 10);
+
+      return {
+        data: dataResult.rows as T[],
+        total,
+        page,
+        limit,
+        totalPages: Math.ceil(total / limit),
+      };
+    }
+
+    const [countRows, dataRows] = await Promise.all([
+      query<{ count: string }>(countSql, params),
+      query<T>(dataSql, [...params, limit, offset]),
+    ]);
+
+    const total = parseInt(countRows[0]?.count || '0', 10);
+
+    return {
+      data: dataRows,
+      total,
+      page,
+      limit,
+      totalPages: Math.ceil(total / limit),
+    };
+  }
+
+  /**
+   * Obtiene un registro por ID
+   */
+  async findById(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<T | null> {
+    let whereClause = 'WHERE id = $1 AND tenant_id = $2';
+
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
+
+    const sql = `
+      SELECT ${this.config.selectFields}
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows[0] as T || null;
+    }
+    const rows = await query<T>(sql, [id, tenantId]);
+    return rows[0] || null;
+  }
+
+  /**
+   * Obtiene un registro por ID o lanza error si no existe
+   */
+  async findByIdOrFail(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<T> {
+    const entity = await this.findById(id, tenantId, options);
+    if (!entity) {
+      throw new NotFoundError(`${this.config.tableName} with id ${id} not found`);
+    }
+    return entity;
+  }
+
+  /**
+   * Verifica si existe un registro
+   */
+  async exists(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    let whereClause = 'WHERE id = $1 AND tenant_id = $2';
+
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
+
+    const sql = `
+      SELECT 1 FROM ${this.fullTableName}
+      ${whereClause}
+      LIMIT 1
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId]);
+    return rows.length > 0;
+  }
+
+  /**
+   * Soft delete de un registro
+   */
+  async softDelete(
+    id: string,
+    tenantId: string,
+    userId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    if (!this.config.softDelete) {
+      throw new ValidationError('Soft delete not enabled for this entity');
+    }
+
+    const sql = `
+      UPDATE ${this.fullTableName}
+      SET deleted_at = CURRENT_TIMESTAMP,
+          deleted_by = $3,
+          updated_at = CURRENT_TIMESTAMP
+      WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL
+      RETURNING id
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId, userId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId, userId]);
+    return rows.length > 0;
+  }
+
+  /**
+   * Hard delete de un registro
+   */
+  async hardDelete(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    const sql = `
+      DELETE FROM ${this.fullTableName}
+      WHERE id = $1 AND tenant_id = $2
+      RETURNING id
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId]);
+    return rows.length > 0;
+  }
+
+  /**
+   * Cuenta registros con filtros
+   */
+  async count(
+    tenantId: string,
+    filters: Record<string, any> = {},
+    options: QueryOptions = {}
+  ): Promise<number> {
+    const params: any[] = [tenantId];
+    let paramIndex = 2;
+    let whereClause = 'WHERE tenant_id = $1';
+
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
+
+    for (const [key, value] of Object.entries(filters)) {
+      if (value !== undefined && value !== null) {
+        whereClause += ` AND ${key} = $${paramIndex++}`;
+        params.push(value);
+      }
+    }
+
+    const sql = `
+      SELECT COUNT(*) as count
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, params);
+      return parseInt(result.rows[0]?.count || '0', 10);
+    }
+    const rows = await query<{ count: string }>(sql, params);
+    return parseInt(rows[0]?.count || '0', 10);
+  }
+
+  /**
+   * Ejecuta una función dentro de una transacción
+   */
+  protected async withTransaction<R>(
+    fn: (client: PoolClient) => Promise<R>
+  ): Promise<R> {
+    const client = await getClient();
+    try {
+      await client.query('BEGIN');
+      const result = await fn(client);
+      await client.query('COMMIT');
+      return result;
+    } catch (error) {
+      await client.query('ROLLBACK');
+      throw error;
+    } finally {
+      client.release();
+    }
+  }
+
+  /**
+   * Sanitiza nombre de campo para prevenir SQL injection
+   */
+  protected sanitizeFieldName(field: string): string {
+    // Solo permite caracteres alfanuméricos y guiones bajos
+    if (!/^[a-zA-Z_][a-zA-Z0-9_]*$/.test(field)) {
+      return this.config.defaultSortField || 'created_at';
+    }
+    return field;
+  }
+
+  /**
+   * Construye un INSERT dinámico
+   */
+  protected buildInsertQuery(
+    data: Record<string, any>,
+    additionalFields: Record<string, any> = {}
+  ): { sql: string; params: any[] } {
+    const allData = { ...data, ...additionalFields };
+    const fields = Object.keys(allData);
+    const values = Object.values(allData);
+    const placeholders = fields.map((_, i) => `$${i + 1}`);
+
+    const sql = `
+      INSERT INTO ${this.fullTableName} (${fields.join(', ')})
+      VALUES (${placeholders.join(', ')})
+      RETURNING ${this.config.selectFields}
+    `;
+
+    return { sql, params: values };
+  }
+
+  /**
+   * Construye un UPDATE dinámico
+   */
+  protected buildUpdateQuery(
+    id: string,
+    tenantId: string,
+    data: Record<string, any>
+  ): { sql: string; params: any[] } {
+    const fields = Object.keys(data).filter(k => data[k] !== undefined);
+    const setClauses = fields.map((f, i) => `${f} = $${i + 1}`);
+    const values = fields.map(f => data[f]);
+
+    // Agregar updated_at automáticamente
+    setClauses.push(`updated_at = CURRENT_TIMESTAMP`);
+
+    const paramIndex = fields.length + 1;
+
+    const sql = `
+      UPDATE ${this.fullTableName}
+      SET ${setClauses.join(', ')}
+      WHERE id = $${paramIndex} AND tenant_id = $${paramIndex + 1}
+      RETURNING ${this.config.selectFields}
+    `;
+
+    return { sql, params: [...values, id, tenantId] };
+  }
+
+  /**
+   * Redondea a N decimales
+   */
+  protected roundToDecimals(value: number, decimals: number = 2): number {
+    const factor = Math.pow(10, decimals);
+    return Math.round(value * factor) / factor;
+  }
+}
+
+export default BaseService;