diff --git a/apps/api/src/pipelines/dto.ts b/apps/api/src/pipelines/dto.ts
index 5f6eaf6..5b208cb 100644
--- a/apps/api/src/pipelines/dto.ts
+++ b/apps/api/src/pipelines/dto.ts
@@ -351,3 +351,16 @@ export class MoveDealDto {
   @Min(0)
   position?: number;
 }
+
+export class MergePipelineDto {
+  @IsString()
+  @MinLength(1)
+  targetPipelineId!: string;
+
+  @IsObject()
+  stageMap!: Record<string, string>;
+
+  @IsOptional()
+  @IsString()
+  leadFormMode?: 'retarget_all';
+}
diff --git a/apps/api/src/pipelines/pipelines.controller.ts b/apps/api/src/pipelines/pipelines.controller.ts
index d5fb47a..bd0d33b 100644
--- a/apps/api/src/pipelines/pipelines.controller.ts
+++ b/apps/api/src/pipelines/pipelines.controller.ts
@@ -17,6 +17,7 @@ import type { Actor } from '../common/record-scope';
 import {
   CreatePipelineDto,
   CreatePipelineStageDto,
+  MergePipelineDto,
   ReorderPipelineStagesDto,
   UpdatePipelineStageDto,
 } from './dto';
@@ -49,6 +50,25 @@ export class PipelinesController {
     return this.pipelinesService.create(user.organizationId, dto.name);
   }
 
+  @Get(':pipelineId/merge-preview')
+  @Roles('owner', 'admin')
+  mergePreview(
+    @CurrentUser() user: { organizationId: string },
+    @Param('pipelineId') pipelineId: string,
+  ) {
+    return this.pipelinesService.mergePreview(user.organizationId, pipelineId);
+  }
+
+  @Post(':pipelineId/merge')
+  @Roles('owner', 'admin')
+  merge(
+    @CurrentUser() user: { organizationId: string },
+    @Param('pipelineId') pipelineId: string,
+    @Body() dto: MergePipelineDto,
+  ) {
+    return this.pipelinesService.merge(user.organizationId, pipelineId, dto);
+  }
+
   @Post(':pipelineId/stages')
   @Roles('owner', 'admin')
   createStage(
diff --git a/apps/api/src/pipelines/pipelines.service.ts b/apps/api/src/pipelines/pipelines.service.ts
index b40039b..82aed65 100644
--- a/apps/api/src/pipelines/pipelines.service.ts
+++ b/apps/api/src/pipelines/pipelines.service.ts
@@ -5,8 +5,10 @@ import {
 } from '@nestjs/common';
 import type {
   DealDto,
+  MergePipelineResultDto,
   PipelineBoardDto,
   PipelineDto,
+  PipelineMergePreviewDto,
   PipelineStageDto,
 } from '@mento/shared';
 import { Prisma } from '@prisma/client';
@@ -14,6 +16,7 @@ import { PrismaService } from '../prisma/prisma.service';
 import { asCustomFields } from '../common/custom-fields';
 import { type Actor, dealAccessWhere } from '../common/record-scope';
 import { decimalToBase, loadOrgRates } from '../common/currency';
+import { assertStageMap, dealStatusForStage } from './pipeline-merge.util';
 
 export const DEFAULT_STAGES = [
   { name: 'سرنخ', isWon: false, isLost: false },
@@ -329,6 +332,181 @@ export class PipelinesService {
     };
   }
 
+  async mergePreview(
+    organizationId: string,
+    sourceId: string,
+  ): Promise<PipelineMergePreviewDto> {
+    const source = await this.getOwnedPipeline(organizationId, sourceId);
+    const dealCounts = await this.prisma.deal.groupBy({
+      by: ['stageId'],
+      where: { organizationId, pipelineId: source.id },
+      _count: { _all: true },
+    });
+    const countByStage = new Map(
+      dealCounts.map((row) => [row.stageId, row._count._all]),
+    );
+    const leadForms = await this.prisma.leadForm.findMany({
+      where: { organizationId, pipelineId: source.id },
+      select: { id: true, name: true, isActive: true },
+      orderBy: { updatedAt: 'desc' },
+    });
+    const targets = await this.prisma.pipeline.findMany({
+      where: { organizationId, id: { not: source.id } },
+      include: { stages: { orderBy: { position: 'asc' } } },
+      orderBy: [{ isDefault: 'desc' }, { name: 'asc' }],
+    });
+
+    const stages = source.stages.map((stage) => ({
+      id: stage.id,
+      name: stage.name,
+      isWon: stage.isWon,
+      isLost: stage.isLost,
+      dealCount: countByStage.get(stage.id) ?? 0,
+    }));
+
+    return {
+      source: {
+        id: source.id,
+        name: source.name,
+        isDefault: source.isDefault,
+      },
+      stages,
+      dealCount: stages.reduce((sum, stage) => sum + stage.dealCount, 0),
+      leadForms,
+      targets: targets.map((target) => ({
+        id: target.id,
+        name: target.name,
+        isDefault: target.isDefault,
+        stages: target.stages.map((stage) => ({
+          id: stage.id,
+          name: stage.name,
+          isWon: stage.isWon,
+          isLost: stage.isLost,
+        })),
+      })),
+    };
+  }
+
+  async merge(
+    organizationId: string,
+    sourceId: string,
+    dto: {
+      targetPipelineId: string;
+      stageMap: Record<string, string>;
+      leadFormMode?: 'retarget_all';
+    },
+  ): Promise<MergePipelineResultDto> {
+    if (sourceId === dto.targetPipelineId) {
+      throw new BadRequestException('مسیر مقصد باید با مسیر مبدأ متفاوت باشد');
+    }
+    if ((dto.leadFormMode ?? 'retarget_all') !== 'retarget_all') {
+      throw new BadRequestException('روش انتقال فرم‌های جذب نامعتبر است');
+    }
+
+    const [source, target] = await Promise.all([
+      this.getOwnedPipeline(organizationId, sourceId),
+      this.getOwnedPipeline(organizationId, dto.targetPipelineId),
+    ]);
+
+    try {
+      assertStageMap(source.stages, target.stages, dto.stageMap);
+    } catch (error) {
+      throw new BadRequestException(
+        error instanceof Error ? error.message : 'نگاشت ستون‌ها نامعتبر است',
+      );
+    }
+
+    const targetStagesById = new Map(target.stages.map((stage) => [stage.id, stage]));
+    let movedDeals = 0;
+    let retargetedLeadForms = 0;
+
+    await this.prisma.$transaction(async (tx) => {
+      const closedAt = new Date();
+      for (const sourceStage of source.stages) {
+        const targetStageId = dto.stageMap[sourceStage.id];
+        const targetStage = targetStagesById.get(targetStageId);
+        if (!targetStage) {
+          throw new BadRequestException('نگاشت ستون‌ها نامعتبر است');
+        }
+        const status = dealStatusForStage(targetStage);
+
+        if (status === 'open') {
+          const result = await tx.deal.updateMany({
+            where: {
+              organizationId,
+              pipelineId: source.id,
+              stageId: sourceStage.id,
+            },
+            data: {
+              pipelineId: target.id,
+              stageId: targetStage.id,
+              status,
+              closedAt: null,
+            },
+          });
+          movedDeals += result.count;
+          continue;
+        }
+
+        const opened = await tx.deal.updateMany({
+          where: {
+            organizationId,
+            pipelineId: source.id,
+            stageId: sourceStage.id,
+            status: 'open',
+          },
+          data: {
+            pipelineId: target.id,
+            stageId: targetStage.id,
+            status,
+            closedAt,
+          },
+        });
+        const alreadyClosed = await tx.deal.updateMany({
+          where: {
+            organizationId,
+            pipelineId: source.id,
+            stageId: sourceStage.id,
+            status: { not: 'open' },
+          },
+          data: {
+            pipelineId: target.id,
+            stageId: targetStage.id,
+            status,
+          },
+        });
+        movedDeals += opened.count + alreadyClosed.count;
+      }
+
+      const leadForms = await tx.leadForm.updateMany({
+        where: { organizationId, pipelineId: source.id },
+        data: { pipelineId: target.id },
+      });
+      retargetedLeadForms = leadForms.count;
+
+      if (source.isDefault) {
+        await tx.pipeline.updateMany({
+          where: { organizationId, isDefault: true },
+          data: { isDefault: false },
+        });
+        await tx.pipeline.update({
+          where: { id: target.id },
+          data: { isDefault: true },
+        });
+      }
+
+      await tx.pipeline.delete({ where: { id: source.id } });
+    });
+
+    return {
+      ok: true,
+      targetPipelineId: target.id,
+      movedDeals,
+      retargetedLeadForms,
+      deletedPipelineId: source.id,
+    };
+  }
+
   toDealDto(row: DealRow): DealDto {
     return {
       id: row.id,