diff --git a/backend/prisma/migrations/20260314000000_multi_user_isolation/migration.sql b/backend/prisma/migrations/20260314000000_multi_user_isolation/migration.sql
new file mode 100644
index 0000000..d0d6b8f
--- /dev/null
+++ b/backend/prisma/migrations/20260314000000_multi_user_isolation/migration.sql
@@ -0,0 +1,36 @@
+-- Delete duplicate admin users first (keep the one with lowest id)
+DELETE FROM "users" WHERE "email" = 'admin@wraith.local' AND "id" != (SELECT MIN("id") FROM "users" WHERE "email" = 'admin@wraith.local');
+
+-- Add role to users
+ALTER TABLE "users" ADD COLUMN "role" TEXT NOT NULL DEFAULT 'user';
+
+-- Backfill admin@wraith.local as admin
+UPDATE "users" SET "role" = 'admin' WHERE "email" = 'admin@wraith.local';
+
+-- Add user_id to all data tables
+ALTER TABLE "hosts" ADD COLUMN "user_id" INTEGER;
+ALTER TABLE "host_groups" ADD COLUMN "user_id" INTEGER;
+ALTER TABLE "credentials" ADD COLUMN "user_id" INTEGER;
+ALTER TABLE "ssh_keys" ADD COLUMN "user_id" INTEGER;
+ALTER TABLE "connection_logs" ADD COLUMN "user_id" INTEGER;
+
+-- Backfill existing data to the admin user
+UPDATE "hosts" SET "user_id" = (SELECT "id" FROM "users" WHERE "email" = 'admin@wraith.local');
+UPDATE "host_groups" SET "user_id" = (SELECT "id" FROM "users" WHERE "email" = 'admin@wraith.local');
+UPDATE "credentials" SET "user_id" = (SELECT "id" FROM "users" WHERE "email" = 'admin@wraith.local');
+UPDATE "ssh_keys" SET "user_id" = (SELECT "id" FROM "users" WHERE "email" = 'admin@wraith.local');
+UPDATE "connection_logs" SET "user_id" = (SELECT "id" FROM "users" WHERE "email" = 'admin@wraith.local');
+
+-- Make user_id NOT NULL after backfill
+ALTER TABLE "hosts" ALTER COLUMN "user_id" SET NOT NULL;
+ALTER TABLE "host_groups" ALTER COLUMN "user_id" SET NOT NULL;
+ALTER TABLE "credentials" ALTER COLUMN "user_id" SET NOT NULL;
+ALTER TABLE "ssh_keys" ALTER COLUMN "user_id" SET NOT NULL;
+ALTER TABLE "connection_logs" ALTER COLUMN "user_id" SET NOT NULL;
+
+-- Add foreign keys
+ALTER TABLE "hosts" ADD CONSTRAINT "hosts_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE;
+ALTER TABLE "host_groups" ADD CONSTRAINT "host_groups_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE;
+ALTER TABLE "credentials" ADD CONSTRAINT "credentials_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE;
+ALTER TABLE "ssh_keys" ADD CONSTRAINT "ssh_keys_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE;
+ALTER TABLE "connection_logs" ADD CONSTRAINT "connection_logs_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE;
diff --git a/backend/prisma/schema.prisma b/backend/prisma/schema.prisma
index 1b03bce..8c69314 100644
--- a/backend/prisma/schema.prisma
+++ b/backend/prisma/schema.prisma
@@ -8,14 +8,20 @@ datasource db {
 }
 
 model User {
-  id            Int       @id @default(autoincrement())
-  email         String    @unique
-  passwordHash  String    @map("password_hash")
-  displayName   String?   @map("display_name")
-  totpSecret    String?   @map("totp_secret")
-  totpEnabled   Boolean   @default(false) @map("totp_enabled")
-  createdAt     DateTime  @default(now()) @map("created_at")
-  updatedAt     DateTime  @updatedAt @map("updated_at")
+  id             Int             @id @default(autoincrement())
+  email          String          @unique
+  passwordHash   String          @map("password_hash")
+  displayName    String?         @map("display_name")
+  role           String          @default("user")
+  totpSecret     String?         @map("totp_secret")
+  totpEnabled    Boolean         @default(false) @map("totp_enabled")
+  createdAt      DateTime        @default(now()) @map("created_at")
+  updatedAt      DateTime        @updatedAt @map("updated_at")
+  hosts          Host[]
+  hostGroups     HostGroup[]
+  credentials    Credential[]
+  sshKeys        SshKey[]
+  connectionLogs ConnectionLog[]
 
   @@map("users")
 }
@@ -24,10 +30,12 @@ model HostGroup {
   id        Int         @id @default(autoincrement())
   name      String
   parentId  Int?        @map("parent_id")
+  userId    Int         @map("user_id")
   sortOrder Int         @default(0) @map("sort_order")
   parent    HostGroup?  @relation("GroupTree", fields: [parentId], references: [id], onDelete: SetNull)
   children  HostGroup[] @relation("GroupTree")
   hosts     Host[]
+  user      User        @relation(fields: [userId], references: [id], onDelete: Cascade)
   createdAt DateTime    @default(now()) @map("created_at")
   updatedAt DateTime    @updatedAt @map("updated_at")
 
@@ -42,6 +50,7 @@ model Host {
   protocol        Protocol         @default(ssh)
   groupId         Int?             @map("group_id")
   credentialId    Int?             @map("credential_id")
+  userId          Int              @map("user_id")
   tags            String[]         @default([])
   notes           String?
   color           String?          @db.VarChar(7)
@@ -50,6 +59,7 @@ model Host {
   lastConnectedAt DateTime?        @map("last_connected_at")
   group           HostGroup?       @relation(fields: [groupId], references: [id], onDelete: SetNull)
   credential      Credential?      @relation(fields: [credentialId], references: [id], onDelete: SetNull)
+  user            User             @relation(fields: [userId], references: [id], onDelete: Cascade)
   connectionLogs  ConnectionLog[]
   createdAt       DateTime         @default(now()) @map("created_at")
   updatedAt       DateTime         @updatedAt @map("updated_at")
@@ -63,9 +73,11 @@ model Credential {
   username        String?
   domain          String?
   type            CredentialType
+  userId          Int            @map("user_id")
   encryptedValue  String?        @map("encrypted_value")
   sshKeyId        Int?           @map("ssh_key_id")
   sshKey          SshKey?        @relation(fields: [sshKeyId], references: [id], onDelete: SetNull)
+  user            User           @relation(fields: [userId], references: [id], onDelete: Cascade)
   hosts           Host[]
   createdAt       DateTime       @default(now()) @map("created_at")
   updatedAt       DateTime       @updatedAt @map("updated_at")
@@ -79,8 +91,10 @@ model SshKey {
   keyType              String       @map("key_type") @db.VarChar(20)
   fingerprint          String?
   publicKey            String?      @map("public_key")
+  userId               Int          @map("user_id")
   encryptedPrivateKey  String       @map("encrypted_private_key")
   passphraseEncrypted  String?      @map("passphrase_encrypted")
+  user                 User         @relation(fields: [userId], references: [id], onDelete: Cascade)
   credentials          Credential[]
   createdAt            DateTime     @default(now()) @map("created_at")
   updatedAt            DateTime     @updatedAt @map("updated_at")
@@ -91,10 +105,12 @@ model SshKey {
 model ConnectionLog {
   id             Int       @id @default(autoincrement())
   hostId         Int       @map("host_id")
+  userId         Int       @map("user_id")
   protocol       Protocol
   connectedAt    DateTime  @default(now()) @map("connected_at")
   disconnectedAt DateTime? @map("disconnected_at")
   host           Host      @relation(fields: [hostId], references: [id], onDelete: Cascade)
+  user           User      @relation(fields: [userId], references: [id], onDelete: Cascade)
 
   @@map("connection_logs")
 }
diff --git a/backend/prisma/seed.ts b/backend/prisma/seed.ts
index ae814b9..334e653 100644
--- a/backend/prisma/seed.ts
+++ b/backend/prisma/seed.ts
@@ -12,9 +12,10 @@ async function main() {
       email: 'admin@wraith.local',
       passwordHash: hash,
       displayName: 'Admin',
+      role: 'admin',
     },
   });
-  console.log('Seed complete: admin@wraith.local / wraith');
+  console.log('Seed complete: admin@wraith.local / wraith (role: admin)');
 }
 
 main()
diff --git a/backend/seed.js b/backend/seed.js
index 041aee8..39df812 100644
--- a/backend/seed.js
+++ b/backend/seed.js
@@ -4,9 +4,9 @@ const bcrypt = require('bcrypt');
 const prisma = new PrismaClient();
 
 async function main() {
-  const userCount = await prisma.user.count();
-  if (userCount > 0) {
-    console.log('Seed: users already exist, skipping');
+  const admin = await prisma.user.findUnique({ where: { email: 'admin@wraith.local' } });
+  if (admin) {
+    console.log('Seed: admin@wraith.local already exists, skipping');
     return;
   }
   const hash = await bcrypt.hash('wraith', 10);
@@ -15,9 +15,10 @@ async function main() {
       email: 'admin@wraith.local',
       passwordHash: hash,
       displayName: 'Admin',
+      role: 'admin',
     },
   });
-  console.log('Seed complete: admin@wraith.local / wraith');
+  console.log('Seed complete: admin@wraith.local / wraith (role: admin)');
 }
 
 main()
diff --git a/backend/src/auth/admin.guard.ts b/backend/src/auth/admin.guard.ts
new file mode 100644
index 0000000..7d58269
--- /dev/null
+++ b/backend/src/auth/admin.guard.ts
@@ -0,0 +1,12 @@
+import { Injectable, CanActivate, ExecutionContext, ForbiddenException } from '@nestjs/common';
+
+@Injectable()
+export class AdminGuard implements CanActivate {
+  canActivate(context: ExecutionContext): boolean {
+    const req = context.switchToHttp().getRequest();
+    if (req.user?.role !== 'admin') {
+      throw new ForbiddenException('Admin access required');
+    }
+    return true;
+  }
+}
diff --git a/backend/src/auth/auth.controller.ts b/backend/src/auth/auth.controller.ts
index a06eb72..dd89473 100644
--- a/backend/src/auth/auth.controller.ts
+++ b/backend/src/auth/auth.controller.ts
@@ -1,6 +1,7 @@
-import { Controller, Post, Get, Put, Body, Request, UseGuards, InternalServerErrorException } from '@nestjs/common';
+import { Controller, Post, Get, Put, Delete, Body, Param, Request, UseGuards, ParseIntPipe, InternalServerErrorException } from '@nestjs/common';
 import { AuthService } from './auth.service';
 import { JwtAuthGuard } from './jwt-auth.guard';
+import { AdminGuard } from './admin.guard';
 import { LoginDto } from './dto/login.dto';
 import { UpdateProfileDto } from './dto/update-profile.dto';
 
@@ -48,4 +49,42 @@ export class AuthController {
   totpDisable(@Request() req: any, @Body() body: { password: string }) {
     return this.auth.totpDisable(req.user.sub, body.password);
   }
+
+  // ─── Admin User Management ──────────────────────────────────────────────
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Get('users')
+  listUsers() {
+    return this.auth.listUsers();
+  }
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Post('users')
+  createUser(@Body() body: { email: string; password: string; displayName?: string; role?: string }) {
+    return this.auth.createUser(body);
+  }
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Put('users/:id')
+  updateUser(@Param('id', ParseIntPipe) id: number, @Request() req: any, @Body() body: { email?: string; displayName?: string; role?: string }) {
+    return this.auth.adminUpdateUser(id, req.user.sub, body);
+  }
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Post('users/:id/reset-password')
+  resetPassword(@Param('id', ParseIntPipe) id: number, @Body() body: { password: string }) {
+    return this.auth.adminResetPassword(id, body.password);
+  }
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Post('users/:id/reset-totp')
+  resetTotp(@Param('id', ParseIntPipe) id: number) {
+    return this.auth.adminResetTotp(id);
+  }
+
+  @UseGuards(JwtAuthGuard, AdminGuard)
+  @Delete('users/:id')
+  deleteUser(@Param('id', ParseIntPipe) id: number, @Request() req: any) {
+    return this.auth.adminDeleteUser(id, req.user.sub);
+  }
 }
diff --git a/backend/src/auth/auth.module.ts b/backend/src/auth/auth.module.ts
index 740c729..04ff422 100644
--- a/backend/src/auth/auth.module.ts
+++ b/backend/src/auth/auth.module.ts
@@ -5,6 +5,7 @@ import { AuthService } from './auth.service';
 import { AuthController } from './auth.controller';
 import { JwtStrategy } from './jwt.strategy';
 import { WsAuthGuard } from './ws-auth.guard';
+import { AdminGuard } from './admin.guard';
 
 @Module({
   imports: [
@@ -14,8 +15,8 @@ import { WsAuthGuard } from './ws-auth.guard';
       signOptions: { expiresIn: '7d' },
     }),
   ],
-  providers: [AuthService, JwtStrategy, WsAuthGuard],
+  providers: [AuthService, JwtStrategy, WsAuthGuard, AdminGuard],
   controllers: [AuthController],
-  exports: [WsAuthGuard, JwtModule],
+  exports: [WsAuthGuard, AdminGuard, JwtModule],
 })
 export class AuthModule {}
diff --git a/backend/src/auth/auth.service.ts b/backend/src/auth/auth.service.ts
index 1d1b295..1991f09 100644
--- a/backend/src/auth/auth.service.ts
+++ b/backend/src/auth/auth.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, UnauthorizedException, BadRequestException } from '@nestjs/common';
+import { Injectable, UnauthorizedException, BadRequestException, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { JwtService } from '@nestjs/jwt';
 import { PrismaService } from '../prisma/prisma.service';
 import * as bcrypt from 'bcrypt';
@@ -34,10 +34,10 @@ export class AuthService {
       if (!verified) throw new UnauthorizedException('Invalid TOTP code');
     }
 
-    const payload = { sub: user.id, email: user.email };
+    const payload = { sub: user.id, email: user.email, role: user.role };
     return {
       access_token: this.jwt.sign(payload),
-      user: { id: user.id, email: user.email, displayName: user.displayName },
+      user: { id: user.id, email: user.email, displayName: user.displayName, role: user.role },
     };
   }
 
@@ -48,6 +48,7 @@ export class AuthService {
       id: user.id,
       email: user.email,
       displayName: user.displayName,
+      role: user.role,
       totpEnabled: user.totpEnabled,
     };
   }
@@ -140,4 +141,81 @@ export class AuthService {
 
     return { message: 'TOTP disabled' };
   }
+
+  // ─── Admin User Management ──────────────────────────────────────────────
+
+  async listUsers() {
+    return this.prisma.user.findMany({
+      select: { id: true, email: true, displayName: true, role: true, totpEnabled: true, createdAt: true },
+      orderBy: { createdAt: 'asc' },
+    });
+  }
+
+  async createUser(data: { email: string; password: string; displayName?: string; role?: string }) {
+    const existing = await this.prisma.user.findUnique({ where: { email: data.email } });
+    if (existing) throw new BadRequestException('Email already in use');
+
+    const hash = await bcrypt.hash(data.password, 10);
+    const user = await this.prisma.user.create({
+      data: {
+        email: data.email,
+        passwordHash: hash,
+        displayName: data.displayName || null,
+        role: data.role || 'user',
+      },
+    });
+    return { id: user.id, email: user.email, displayName: user.displayName, role: user.role };
+  }
+
+  async adminUpdateUser(targetId: number, adminId: number, data: { email?: string; displayName?: string; role?: string }) {
+    const target = await this.prisma.user.findUnique({ where: { id: targetId } });
+    if (!target) throw new NotFoundException('User not found');
+
+    // Prevent removing your own admin role
+    if (targetId === adminId && data.role && data.role !== 'admin') {
+      throw new ForbiddenException('Cannot remove your own admin role');
+    }
+
+    return this.prisma.user.update({
+      where: { id: targetId },
+      data: {
+        email: data.email,
+        displayName: data.displayName,
+        role: data.role,
+      },
+      select: { id: true, email: true, displayName: true, role: true },
+    });
+  }
+
+  async adminResetPassword(targetId: number, newPassword: string) {
+    const target = await this.prisma.user.findUnique({ where: { id: targetId } });
+    if (!target) throw new NotFoundException('User not found');
+
+    const hash = await bcrypt.hash(newPassword, 10);
+    await this.prisma.user.update({ where: { id: targetId }, data: { passwordHash: hash } });
+    return { message: 'Password reset' };
+  }
+
+  async adminResetTotp(targetId: number) {
+    const target = await this.prisma.user.findUnique({ where: { id: targetId } });
+    if (!target) throw new NotFoundException('User not found');
+
+    await this.prisma.user.update({
+      where: { id: targetId },
+      data: { totpEnabled: false, totpSecret: null },
+    });
+    return { message: 'TOTP reset' };
+  }
+
+  async adminDeleteUser(targetId: number, adminId: number) {
+    if (targetId === adminId) {
+      throw new ForbiddenException('Cannot delete your own account');
+    }
+    const target = await this.prisma.user.findUnique({ where: { id: targetId } });
+    if (!target) throw new NotFoundException('User not found');
+
+    // CASCADE will delete all their hosts, credentials, keys, logs
+    await this.prisma.user.delete({ where: { id: targetId } });
+    return { message: 'User deleted' };
+  }
 }
diff --git a/backend/src/auth/jwt.strategy.ts b/backend/src/auth/jwt.strategy.ts
index 7bd78ae..d26c5ba 100644
--- a/backend/src/auth/jwt.strategy.ts
+++ b/backend/src/auth/jwt.strategy.ts
@@ -12,7 +12,7 @@ export class JwtStrategy extends PassportStrategy(Strategy) {
     });
   }
 
-  validate(payload: { sub: number; email: string }) {
-    return { sub: payload.sub, email: payload.email };
+  validate(payload: { sub: number; email: string; role: string }) {
+    return { sub: payload.sub, email: payload.email, role: payload.role };
   }
 }
diff --git a/backend/src/connections/groups.controller.ts b/backend/src/connections/groups.controller.ts
index 71373ea..0554cf5 100644
--- a/backend/src/connections/groups.controller.ts
+++ b/backend/src/connections/groups.controller.ts
@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Put, Delete, Param, Body, UseGuards, ParseIntPipe } from '@nestjs/common';
+import { Controller, Get, Post, Put, Delete, Param, Body, Request, UseGuards, ParseIntPipe } from '@nestjs/common';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
 import { GroupsService } from './groups.service';
 import { CreateGroupDto } from './dto/create-group.dto';
@@ -10,32 +10,32 @@ export class GroupsController {
   constructor(private groups: GroupsService) {}
 
   @Get()
-  findAll() {
-    return this.groups.findAll();
+  findAll(@Request() req: any) {
+    return this.groups.findAll(req.user.sub);
   }
 
   @Get('tree')
-  findTree() {
-    return this.groups.findTree();
+  findTree(@Request() req: any) {
+    return this.groups.findTree(req.user.sub);
   }
 
   @Get(':id')
-  findOne(@Param('id', ParseIntPipe) id: number) {
-    return this.groups.findOne(id);
+  findOne(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.groups.findOne(id, req.user.sub);
   }
 
   @Post()
-  create(@Body() dto: CreateGroupDto) {
-    return this.groups.create(dto);
+  create(@Request() req: any, @Body() dto: CreateGroupDto) {
+    return this.groups.create(req.user.sub, dto);
   }
 
   @Put(':id')
-  update(@Param('id', ParseIntPipe) id: number, @Body() dto: UpdateGroupDto) {
-    return this.groups.update(id, dto);
+  update(@Request() req: any, @Param('id', ParseIntPipe) id: number, @Body() dto: UpdateGroupDto) {
+    return this.groups.update(id, req.user.sub, dto);
   }
 
   @Delete(':id')
-  remove(@Param('id', ParseIntPipe) id: number) {
-    return this.groups.remove(id);
+  remove(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.groups.remove(id, req.user.sub);
   }
 }
diff --git a/backend/src/connections/groups.service.ts b/backend/src/connections/groups.service.ts
index 458205f..4ae0ceb 100644
--- a/backend/src/connections/groups.service.ts
+++ b/backend/src/connections/groups.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { CreateGroupDto } from './dto/create-group.dto';
 import { UpdateGroupDto } from './dto/update-group.dto';
@@ -7,16 +7,17 @@ import { UpdateGroupDto } from './dto/update-group.dto';
 export class GroupsService {
   constructor(private prisma: PrismaService) {}
 
-  findAll() {
+  findAll(userId: number) {
     return this.prisma.hostGroup.findMany({
+      where: { userId },
       include: { children: true, hosts: { select: { id: true, name: true, protocol: true } } },
       orderBy: { sortOrder: 'asc' },
     });
   }
 
-  findTree() {
+  findTree(userId: number) {
     return this.prisma.hostGroup.findMany({
-      where: { parentId: null },
+      where: { parentId: null, userId },
       include: {
         hosts: { orderBy: { sortOrder: 'asc' } },
         children: {
@@ -35,26 +36,27 @@ export class GroupsService {
     });
   }
 
-  async findOne(id: number) {
+  async findOne(id: number, userId: number) {
     const group = await this.prisma.hostGroup.findUnique({
       where: { id },
       include: { hosts: true, children: true },
     });
     if (!group) throw new NotFoundException(`Group ${id} not found`);
+    if (group.userId !== userId) throw new ForbiddenException('Access denied');
     return group;
   }
 
-  create(dto: CreateGroupDto) {
-    return this.prisma.hostGroup.create({ data: dto });
+  create(userId: number, dto: CreateGroupDto) {
+    return this.prisma.hostGroup.create({ data: { ...dto, userId } });
   }
 
-  async update(id: number, dto: UpdateGroupDto) {
-    await this.findOne(id);
+  async update(id: number, userId: number, dto: UpdateGroupDto) {
+    await this.findOne(id, userId);
     return this.prisma.hostGroup.update({ where: { id }, data: dto });
   }
 
-  async remove(id: number) {
-    await this.findOne(id);
+  async remove(id: number, userId: number) {
+    await this.findOne(id, userId);
     return this.prisma.hostGroup.delete({ where: { id } });
   }
 }
diff --git a/backend/src/connections/hosts.controller.ts b/backend/src/connections/hosts.controller.ts
index 88057f7..acb9c71 100644
--- a/backend/src/connections/hosts.controller.ts
+++ b/backend/src/connections/hosts.controller.ts
@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Put, Delete, Param, Body, Query, UseGuards, ParseIntPipe } from '@nestjs/common';
+import { Controller, Get, Post, Put, Delete, Param, Body, Query, Request, UseGuards, ParseIntPipe } from '@nestjs/common';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
 import { HostsService } from './hosts.service';
 import { CreateHostDto } from './dto/create-host.dto';
@@ -10,32 +10,32 @@ export class HostsController {
   constructor(private hosts: HostsService) {}
 
   @Get()
-  findAll(@Query('search') search?: string) {
-    return this.hosts.findAll(search);
+  findAll(@Request() req: any, @Query('search') search?: string) {
+    return this.hosts.findAll(req.user.sub, search);
   }
 
   @Get(':id')
-  findOne(@Param('id', ParseIntPipe) id: number) {
-    return this.hosts.findOne(id);
+  findOne(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.hosts.findOne(id, req.user.sub);
   }
 
   @Post()
-  create(@Body() dto: CreateHostDto) {
-    return this.hosts.create(dto);
+  create(@Request() req: any, @Body() dto: CreateHostDto) {
+    return this.hosts.create(req.user.sub, dto);
   }
 
   @Put(':id')
-  update(@Param('id', ParseIntPipe) id: number, @Body() dto: UpdateHostDto) {
-    return this.hosts.update(id, dto);
+  update(@Request() req: any, @Param('id', ParseIntPipe) id: number, @Body() dto: UpdateHostDto) {
+    return this.hosts.update(id, req.user.sub, dto);
   }
 
   @Delete(':id')
-  remove(@Param('id', ParseIntPipe) id: number) {
-    return this.hosts.remove(id);
+  remove(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.hosts.remove(id, req.user.sub);
   }
 
   @Post('reorder')
-  reorder(@Body() body: { ids: number[] }) {
-    return this.hosts.reorder(body.ids);
+  reorder(@Request() req: any, @Body() body: { ids: number[] }) {
+    return this.hosts.reorder(req.user.sub, body.ids);
   }
 }
diff --git a/backend/src/connections/hosts.service.ts b/backend/src/connections/hosts.service.ts
index a807af6..b49d4ce 100644
--- a/backend/src/connections/hosts.service.ts
+++ b/backend/src/connections/hosts.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { CreateHostDto } from './dto/create-host.dto';
 import { UpdateHostDto } from './dto/update-host.dto';
@@ -7,16 +7,15 @@ import { UpdateHostDto } from './dto/update-host.dto';
 export class HostsService {
   constructor(private prisma: PrismaService) {}
 
-  findAll(search?: string) {
-    const where = search
-      ? {
-          OR: [
-            { name: { contains: search, mode: 'insensitive' as const } },
-            { hostname: { contains: search, mode: 'insensitive' as const } },
-            { tags: { has: search } },
-          ],
-        }
-      : {};
+  findAll(userId: number, search?: string) {
+    const where: any = { userId };
+    if (search) {
+      where.OR = [
+        { name: { contains: search, mode: 'insensitive' as const } },
+        { hostname: { contains: search, mode: 'insensitive' as const } },
+        { tags: { has: search } },
+      ];
+    }
     return this.prisma.host.findMany({
       where,
       include: { group: true, credential: { select: { id: true, name: true, type: true } } },
@@ -24,16 +23,19 @@ export class HostsService {
     });
   }
 
-  async findOne(id: number) {
+  async findOne(id: number, userId?: number) {
     const host = await this.prisma.host.findUnique({
       where: { id },
       include: { group: true, credential: true },
     });
     if (!host) throw new NotFoundException(`Host ${id} not found`);
+    if (userId !== undefined && host.userId !== userId) {
+      throw new ForbiddenException('Access denied');
+    }
     return host;
   }
 
-  create(dto: CreateHostDto) {
+  create(userId: number, dto: CreateHostDto) {
     return this.prisma.host.create({
       data: {
         name: dto.name,
@@ -42,6 +44,7 @@ export class HostsService {
         protocol: dto.protocol ?? 'ssh',
         groupId: dto.groupId,
         credentialId: dto.credentialId,
+        userId,
         tags: dto.tags ?? [],
         notes: dto.notes,
         color: dto.color,
@@ -50,13 +53,13 @@ export class HostsService {
     });
   }
 
-  async update(id: number, dto: UpdateHostDto) {
-    await this.findOne(id); // throws if not found
+  async update(id: number, userId: number, dto: UpdateHostDto) {
+    await this.findOne(id, userId);
     return this.prisma.host.update({ where: { id }, data: dto });
   }
 
-  async remove(id: number) {
-    await this.findOne(id);
+  async remove(id: number, userId: number) {
+    await this.findOne(id, userId);
     return this.prisma.host.delete({ where: { id } });
   }
 
@@ -67,7 +70,11 @@ export class HostsService {
     });
   }
 
-  async reorder(ids: number[]) {
+  async reorder(userId: number, ids: number[]) {
+    // Verify all hosts belong to user
+    const hosts = await this.prisma.host.findMany({ where: { id: { in: ids }, userId } });
+    if (hosts.length !== ids.length) throw new ForbiddenException('Access denied');
+
     const updates = ids.map((id, index) =>
       this.prisma.host.update({ where: { id }, data: { sortOrder: index } }),
     );
diff --git a/backend/src/rdp/rdp.gateway.ts b/backend/src/rdp/rdp.gateway.ts
index 4c3d11e..b7a0002 100644
--- a/backend/src/rdp/rdp.gateway.ts
+++ b/backend/src/rdp/rdp.gateway.ts
@@ -12,6 +12,7 @@ export class RdpGateway {
 
   // Maps browser WebSocket client → live guacd TCP socket
   private clientSockets = new Map<any, net.Socket>();
+  private clientUsers = new Map<any, { sub: number; email: string }>();
 
   constructor(
     private guacamole: GuacamoleService,
@@ -28,6 +29,7 @@ export class RdpGateway {
       return;
     }
 
+    this.clientUsers.set(client, user);
     this.logger.log(`RDP WS connected: ${user.email}`);
 
     client.on('message', async (raw: Buffer) => {
@@ -58,6 +60,7 @@ export class RdpGateway {
         this.clientSockets.delete(client);
         this.logger.log('guacd socket destroyed on WS close');
       }
+      this.clientUsers.delete(client);
     });
   }
 
@@ -129,9 +132,10 @@ export class RdpGateway {
     });
 
     // Connection tracking
+    const wsUser = this.clientUsers.get(client);
     this.hosts.touchLastConnected(host.id).catch(() => {});
     this.prisma.connectionLog
-      .create({ data: { hostId: host.id, protocol: 'rdp' } })
+      .create({ data: { hostId: host.id, userId: wsUser!.sub, protocol: 'rdp' } })
       .catch(() => {});
 
     this.send(client, { type: 'connected', hostId: host.id, hostName: host.name });
diff --git a/backend/src/terminal/ssh-connection.service.ts b/backend/src/terminal/ssh-connection.service.ts
index 359a6dd..d5fc621 100644
--- a/backend/src/terminal/ssh-connection.service.ts
+++ b/backend/src/terminal/ssh-connection.service.ts
@@ -26,6 +26,7 @@ export class SshConnectionService {
 
   async connect(
     hostId: number,
+    userId: number,
     onData: (data: string) => void,
     onClose: (reason: string) => void,
     onHostKeyVerify: (fingerprint: string, isNew: boolean) => Promise<boolean>,
@@ -71,7 +72,7 @@ export class SshConnectionService {
           // Update lastConnectedAt and create connection log
           this.hosts.touchLastConnected(hostId);
           this.prisma.connectionLog.create({
-            data: { hostId, protocol: host.protocol },
+            data: { hostId, userId, protocol: host.protocol },
           }).catch(() => {});
 
           resolve(sessionId);
diff --git a/backend/src/terminal/terminal.gateway.ts b/backend/src/terminal/terminal.gateway.ts
index 8f6d11e..dbba200 100644
--- a/backend/src/terminal/terminal.gateway.ts
+++ b/backend/src/terminal/terminal.gateway.ts
@@ -6,6 +6,7 @@ import { SshConnectionService } from './ssh-connection.service';
 export class TerminalGateway {
   private readonly logger = new Logger(TerminalGateway.name);
   private clientSessions = new Map<any, string[]>(); // ws client → sessionIds
+  private clientUsers = new Map<any, { sub: number; email: string }>(); // ws client → user
 
   constructor(
     private ssh: SshConnectionService,
@@ -21,6 +22,7 @@ export class TerminalGateway {
       return;
     }
     this.clientSessions.set(client, []);
+    this.clientUsers.set(client, user);
     this.logger.log(`[WS] Terminal connected: ${user.email}`);
 
     client.on('message', async (raw: Buffer) => {
@@ -39,6 +41,7 @@ export class TerminalGateway {
       const sessions = this.clientSessions.get(client) || [];
       sessions.forEach((sid) => this.ssh.disconnect(sid));
       this.clientSessions.delete(client);
+      this.clientUsers.delete(client);
     });
   }
 
@@ -46,9 +49,11 @@ export class TerminalGateway {
     switch (msg.type) {
       case 'connect': {
         let sessionId = '';
+        const wsUser = this.clientUsers.get(client);
         try {
           sessionId = await this.ssh.connect(
             msg.hostId,
+            wsUser!.sub,
             (data) => this.send(client, { type: 'data', sessionId, data }),
             (reason) => this.send(client, { type: 'disconnected', sessionId, reason }),
             async (fingerprint, isNew) => {
diff --git a/backend/src/vault/credentials.controller.ts b/backend/src/vault/credentials.controller.ts
index 1cd323d..7d67c21 100644
--- a/backend/src/vault/credentials.controller.ts
+++ b/backend/src/vault/credentials.controller.ts
@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Put, Delete, Param, Body, UseGuards, ParseIntPipe } from '@nestjs/common';
+import { Controller, Get, Post, Put, Delete, Param, Body, Request, UseGuards, ParseIntPipe } from '@nestjs/common';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
 import { CredentialsService } from './credentials.service';
 import { CreateCredentialDto } from './dto/create-credential.dto';
@@ -10,27 +10,27 @@ export class CredentialsController {
   constructor(private credentials: CredentialsService) {}
 
   @Get()
-  findAll() {
-    return this.credentials.findAll();
+  findAll(@Request() req: any) {
+    return this.credentials.findAll(req.user.sub);
   }
 
   @Get(':id')
-  findOne(@Param('id', ParseIntPipe) id: number) {
-    return this.credentials.findOne(id);
+  findOne(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.credentials.findOne(id, req.user.sub);
   }
 
   @Post()
-  create(@Body() dto: CreateCredentialDto) {
-    return this.credentials.create(dto);
+  create(@Request() req: any, @Body() dto: CreateCredentialDto) {
+    return this.credentials.create(req.user.sub, dto);
   }
 
   @Put(':id')
-  update(@Param('id', ParseIntPipe) id: number, @Body() dto: UpdateCredentialDto) {
-    return this.credentials.update(id, dto);
+  update(@Request() req: any, @Param('id', ParseIntPipe) id: number, @Body() dto: UpdateCredentialDto) {
+    return this.credentials.update(id, req.user.sub, dto);
   }
 
   @Delete(':id')
-  remove(@Param('id', ParseIntPipe) id: number) {
-    return this.credentials.remove(id);
+  remove(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.credentials.remove(id, req.user.sub);
   }
 }
diff --git a/backend/src/vault/credentials.service.ts b/backend/src/vault/credentials.service.ts
index 2741324..eef92b0 100644
--- a/backend/src/vault/credentials.service.ts
+++ b/backend/src/vault/credentials.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { EncryptionService } from './encryption.service';
 import { CreateCredentialDto } from './dto/create-credential.dto';
@@ -11,23 +11,27 @@ export class CredentialsService {
     private encryption: EncryptionService,
   ) {}
 
-  findAll() {
+  findAll(userId: number) {
     return this.prisma.credential.findMany({
+      where: { userId },
       include: { sshKey: { select: { id: true, name: true, keyType: true, fingerprint: true } } },
       orderBy: { name: 'asc' },
     });
   }
 
-  async findOne(id: number) {
+  async findOne(id: number, userId?: number) {
     const cred = await this.prisma.credential.findUnique({
       where: { id },
       include: { sshKey: true, hosts: { select: { id: true, name: true } } },
     });
     if (!cred) throw new NotFoundException(`Credential ${id} not found`);
+    if (userId !== undefined && cred.userId !== userId) {
+      throw new ForbiddenException('Access denied');
+    }
     return cred;
   }
 
-  create(dto: CreateCredentialDto) {
+  create(userId: number, dto: CreateCredentialDto) {
     const encryptedValue = dto.password ? this.encryption.encrypt(dto.password) : null;
     return this.prisma.credential.create({
       data: {
@@ -35,14 +39,15 @@ export class CredentialsService {
         username: dto.username,
         domain: dto.domain,
         type: dto.type,
+        userId,
         encryptedValue,
         sshKeyId: dto.sshKeyId,
       },
     });
   }
 
-  async update(id: number, dto: UpdateCredentialDto) {
-    await this.findOne(id);
+  async update(id: number, userId: number, dto: UpdateCredentialDto) {
+    await this.findOne(id, userId);
     const data: any = { ...dto };
     delete data.password;
     if (dto.password) {
@@ -51,8 +56,8 @@ export class CredentialsService {
     return this.prisma.credential.update({ where: { id }, data });
   }
 
-  async remove(id: number) {
-    await this.findOne(id);
+  async remove(id: number, userId: number) {
+    await this.findOne(id, userId);
     return this.prisma.credential.delete({ where: { id } });
   }
 
diff --git a/backend/src/vault/ssh-keys.controller.ts b/backend/src/vault/ssh-keys.controller.ts
index ae234e8..0a7627a 100644
--- a/backend/src/vault/ssh-keys.controller.ts
+++ b/backend/src/vault/ssh-keys.controller.ts
@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Put, Delete, Param, Body, UseGuards, ParseIntPipe } from '@nestjs/common';
+import { Controller, Get, Post, Put, Delete, Param, Body, Request, UseGuards, ParseIntPipe } from '@nestjs/common';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
 import { SshKeysService } from './ssh-keys.service';
 import { CreateSshKeyDto } from './dto/create-ssh-key.dto';
@@ -10,27 +10,27 @@ export class SshKeysController {
   constructor(private sshKeys: SshKeysService) {}
 
   @Get()
-  findAll() {
-    return this.sshKeys.findAll();
+  findAll(@Request() req: any) {
+    return this.sshKeys.findAll(req.user.sub);
   }
 
   @Get(':id')
-  findOne(@Param('id', ParseIntPipe) id: number) {
-    return this.sshKeys.findOne(id);
+  findOne(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.sshKeys.findOne(id, req.user.sub);
   }
 
   @Post()
-  create(@Body() dto: CreateSshKeyDto) {
-    return this.sshKeys.create(dto);
+  create(@Request() req: any, @Body() dto: CreateSshKeyDto) {
+    return this.sshKeys.create(req.user.sub, dto);
   }
 
   @Put(':id')
-  update(@Param('id', ParseIntPipe) id: number, @Body() dto: UpdateSshKeyDto) {
-    return this.sshKeys.update(id, dto);
+  update(@Request() req: any, @Param('id', ParseIntPipe) id: number, @Body() dto: UpdateSshKeyDto) {
+    return this.sshKeys.update(id, req.user.sub, dto);
   }
 
   @Delete(':id')
-  remove(@Param('id', ParseIntPipe) id: number) {
-    return this.sshKeys.remove(id);
+  remove(@Request() req: any, @Param('id', ParseIntPipe) id: number) {
+    return this.sshKeys.remove(id, req.user.sub);
   }
 }
diff --git a/backend/src/vault/ssh-keys.service.ts b/backend/src/vault/ssh-keys.service.ts
index 71e6c2a..a38794c 100644
--- a/backend/src/vault/ssh-keys.service.ts
+++ b/backend/src/vault/ssh-keys.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { EncryptionService } from './encryption.service';
 import { CreateSshKeyDto } from './dto/create-ssh-key.dto';
@@ -12,19 +12,23 @@ export class SshKeysService {
     private encryption: EncryptionService,
   ) {}
 
-  findAll() {
+  findAll(userId: number) {
     return this.prisma.sshKey.findMany({
+      where: { userId },
       select: { id: true, name: true, keyType: true, fingerprint: true, publicKey: true, createdAt: true },
       orderBy: { name: 'asc' },
     });
   }
 
-  async findOne(id: number) {
+  async findOne(id: number, userId?: number) {
     const key = await this.prisma.sshKey.findUnique({
       where: { id },
       include: { credentials: { select: { id: true, name: true } } },
     });
     if (!key) throw new NotFoundException(`SSH key ${id} not found`);
+    if (userId !== undefined && key.userId !== userId) {
+      throw new ForbiddenException('Access denied');
+    }
     // Never return encrypted private key over API
     return {
       id: key.id,
@@ -37,7 +41,7 @@ export class SshKeysService {
     };
   }
 
-  async create(dto: CreateSshKeyDto) {
+  async create(userId: number, dto: CreateSshKeyDto) {
     // Detect key type from private key content
     const keyType = this.detectKeyType(dto.privateKey);
 
@@ -56,15 +60,17 @@ export class SshKeysService {
         keyType,
         fingerprint,
         publicKey: dto.publicKey || null,
+        userId,
         encryptedPrivateKey,
         passphraseEncrypted,
       },
     });
   }
 
-  async update(id: number, dto: UpdateSshKeyDto) {
+  async update(id: number, userId: number, dto: UpdateSshKeyDto) {
     const key = await this.prisma.sshKey.findUnique({ where: { id } });
     if (!key) throw new NotFoundException(`SSH key ${id} not found`);
+    if (key.userId !== userId) throw new ForbiddenException('Access denied');
 
     const data: any = {};
     if (dto.name) data.name = dto.name;
@@ -76,9 +82,10 @@ export class SshKeysService {
     return this.prisma.sshKey.update({ where: { id }, data });
   }
 
-  async remove(id: number) {
+  async remove(id: number, userId: number) {
     const key = await this.prisma.sshKey.findUnique({ where: { id } });
     if (!key) throw new NotFoundException(`SSH key ${id} not found`);
+    if (key.userId !== userId) throw new ForbiddenException('Access denied');
     return this.prisma.sshKey.delete({ where: { id } });
   }
 
diff --git a/frontend/stores/auth.store.ts b/frontend/stores/auth.store.ts
index a9ed9da..2518e1c 100644
--- a/frontend/stores/auth.store.ts
+++ b/frontend/stores/auth.store.ts
@@ -4,6 +4,7 @@ interface User {
   id: number
   email: string
   displayName: string | null
+  role: string
   totpEnabled?: boolean
 }
 
@@ -20,6 +21,7 @@ export const useAuthStore = defineStore('auth', {
   }),
   getters: {
     isAuthenticated: (state) => !!state.token,
+    isAdmin: (state) => state.user?.role === 'admin',
   },
   actions: {
     async login(email: string, password: string, totpCode?: string): Promise<LoginResponse> {