diff --git a/src/modules/account/account.module.ts b/src/modules/account/account.module.ts
index 53b0c1b..ec529b8 100644
--- a/src/modules/account/account.module.ts
+++ b/src/modules/account/account.module.ts
@@ -28,6 +28,6 @@ import { DomainRepository } from './repositories/domain.repository.js';
     DomainRepository,
     AccountService,
   ],
-  exports: [AccountService, DomainRepository],
+  exports: [AccountService],
 })
 export class AccountModule {}
diff --git a/src/modules/account/account.service.ts b/src/modules/account/account.service.ts
index 0644fc3..ba400ad 100644
--- a/src/modules/account/account.service.ts
+++ b/src/modules/account/account.service.ts
@@ -8,6 +8,7 @@ import {
 } from '@nestjs/common';
 import { AccountProvider } from './account-provider.port.js';
 import { MailAccount } from './domain/mail-account.domain.js';
+import { MailDomain } from './domain/mail-domain.domain.js';
 import { AccountRepository } from './repositories/account.repository.js';
 import { AddressRepository } from './repositories/address.repository.js';
 import { DomainRepository } from './repositories/domain.repository.js';
@@ -27,6 +28,10 @@ export class AccountService {
     return this.getAccountOrFail(userId);
   }
 
+  async listActiveDomains(): Promise<MailDomain[]> {
+    return this.domains.findAllActive();
+  }
+
   async findAccount(userId: string): Promise<MailAccount | null> {
     return this.accounts.findByUserId(userId);
   }
diff --git a/src/modules/email/email.controller.spec.ts b/src/modules/email/email.controller.spec.ts
index 1693421..e560c07 100644
--- a/src/modules/email/email.controller.spec.ts
+++ b/src/modules/email/email.controller.spec.ts
@@ -38,7 +38,7 @@ describe('EmailController', () => {
   });
 
   describe('list', () => {
-    it('When list is called with no query params, then it uses defaults', async () => {
+    it('when called with no query params, then it lists all emails', async () => {
       const response = {
         emails: [newEmailSummary()],
         total: 1,
@@ -46,11 +46,11 @@ describe('EmailController', () => {
       };
       emailService.listEmails.mockResolvedValue(response);
 
-      const result = await controller.list(userEmail, 'inbox');
+      const result = await controller.list(userEmail);
 
       expect(emailService.listEmails).toHaveBeenCalledWith(
         userEmail,
-        'inbox',
+        undefined,
         20,
         0,
         undefined,
@@ -58,25 +58,43 @@ describe('EmailController', () => {
       expect(result).toBe(response);
     });
 
-    it('When list is called with limit and position, then it parses them', async () => {
+    it('when called with a mailbox filter, then it filters by mailbox', async () => {
       emailService.listEmails.mockResolvedValue({
         emails: [],
         total: 0,
         hasMoreMails: false,
       });
 
-      await controller.list(userEmail, 'sent', '10', '5');
+      await controller.list(userEmail, 'inbox');
+
+      expect(emailService.listEmails).toHaveBeenCalledWith(
+        userEmail,
+        'inbox',
+        20,
+        0,
+        undefined,
+      );
+    });
+
+    it('when called with limit, position and anchorId, then it parses them', async () => {
+      emailService.listEmails.mockResolvedValue({
+        emails: [],
+        total: 0,
+        hasMoreMails: false,
+      });
+
+      await controller.list(userEmail, 'sent', '10', '5', 'Ma1f09b');
 
       expect(emailService.listEmails).toHaveBeenCalledWith(
         userEmail,
         'sent',
         10,
         5,
-        undefined,
+        'Ma1f09b',
       );
     });
 
-    it('When list is called with non-numeric strings, then it falls back to defaults', async () => {
+    it('when called with non-numeric strings, then it falls back to defaults', async () => {
       emailService.listEmails.mockResolvedValue({
         emails: [],
         total: 0,
diff --git a/src/modules/email/email.controller.ts b/src/modules/email/email.controller.ts
index 635e713..aa3b42b 100644
--- a/src/modules/email/email.controller.ts
+++ b/src/modules/email/email.controller.ts
@@ -58,13 +58,14 @@ export class EmailController {
   @ApiOperation({
     summary: 'List emails',
     description:
-      'Paginated list of email summaries for a given mailbox. Defaults to the inbox.',
+      'Paginated list of email summaries. Filter by mailbox or omit to list all.',
   })
   @ApiQuery({
     name: 'mailbox',
     required: false,
     enum: ['inbox', 'drafts', 'sent', 'trash', 'spam', 'archive'],
-    description: 'Mailbox to list. Defaults to `inbox`.',
+    description:
+      'Mailbox to filter by. Omit to list emails from all mailboxes.',
   })
   @ApiQuery({
     name: 'limit',
@@ -90,14 +91,14 @@ export class EmailController {
   @ApiOkResponse({ type: EmailListResponseDto })
   list(
     @User('email') email: string,
-    @Query('mailbox') mailbox: MailboxType = 'inbox',
+    @Query('mailbox') mailbox?: MailboxType,
     @Query('limit') limit?: string,
     @Query('position') position?: string,
     @Query('anchorId') anchorId?: string,
   ) {
     return this.emailService.listEmails(
       email,
-      mailbox,
+      mailbox ?? undefined,
       limit ? Number(limit) || 20 : 20,
       position ? Number(position) || 0 : 0,
       anchorId,
diff --git a/src/modules/email/email.dto.ts b/src/modules/email/email.dto.ts
index d1180c2..5932208 100644
--- a/src/modules/email/email.dto.ts
+++ b/src/modules/email/email.dto.ts
@@ -107,6 +107,9 @@ export class EmailSummaryResponseDto {
   @ApiProperty({ example: 'Ma1f09b…' })
   id!: string;
 
+  @ApiProperty({ type: [String], example: ['d', 'a'] })
+  mailboxIds!: string[];
+
   @ApiProperty({ example: 'T1a2b3c…' })
   threadId!: string;
 
diff --git a/src/modules/email/email.service.spec.ts b/src/modules/email/email.service.spec.ts
index ac8f531..075a70b 100644
--- a/src/modules/email/email.service.spec.ts
+++ b/src/modules/email/email.service.spec.ts
@@ -1,7 +1,9 @@
-import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { describe, it, expect, beforeEach } from 'vitest';
+import { Test } from '@nestjs/testing';
 import { NotFoundException, BadRequestException } from '@nestjs/common';
+import { createMock, type DeepMocked } from '@golevelup/ts-vitest';
 import { EmailService } from './email.service.js';
-import { type MailProvider } from './mail-provider.port.js';
+import { MailProvider } from './mail-provider.port.js';
 import {
   newMailbox,
   newEmail,
@@ -10,32 +12,20 @@ import {
   newDraftEmailDto,
 } from '../../../test/fixtures.js';
 
-type MockMailProvider = {
-  [K in keyof MailProvider]: ReturnType<typeof vi.fn>;
-};
-
-function createMockMailProvider(): MockMailProvider {
-  return {
-    getMailboxes: vi.fn(),
-    listEmails: vi.fn(),
-    getEmail: vi.fn(),
-    sendEmail: vi.fn(),
-    saveDraft: vi.fn(),
-    moveEmail: vi.fn(),
-    deleteEmail: vi.fn(),
-    markAsRead: vi.fn(),
-    markAsFlagged: vi.fn(),
-  };
-}
-
 describe('EmailService', () => {
   let service: EmailService;
-  let provider: MockMailProvider;
+  let provider: DeepMocked<MailProvider>;
   const userEmail = 'test@example.com';
 
-  beforeEach(() => {
-    provider = createMockMailProvider();
-    service = new EmailService(provider);
+  beforeEach(async () => {
+    const module = await Test.createTestingModule({
+      providers: [EmailService],
+    })
+      .useMocker(() => createMock<MailProvider>())
+      .compile();
+
+    service = module.get(EmailService);
+    provider = module.get<DeepMocked<MailProvider>>(MailProvider);
   });
 
   describe('getMailboxes', () => {
@@ -51,10 +41,12 @@ describe('EmailService', () => {
   });
 
   describe('listEmails', () => {
-    it('when called, then delegates with all parameters', async () => {
+    it('when called with a mailbox, then delegates with mailbox', async () => {
       const response = {
         emails: [newEmailSummary()],
         total: 1,
+        hasMoreMails: false,
+        nextAnchor: undefined,
       };
       provider.listEmails.mockResolvedValue(response);
 
@@ -69,6 +61,27 @@ describe('EmailService', () => {
       );
       expect(result).toBe(response);
     });
+
+    it('when called without a mailbox, then delegates with undefined', async () => {
+      const response = {
+        emails: [newEmailSummary()],
+        total: 1,
+        hasMoreMails: false,
+        nextAnchor: undefined,
+      };
+      provider.listEmails.mockResolvedValue(response);
+
+      const result = await service.listEmails(userEmail, undefined, 20, 0);
+
+      expect(provider.listEmails).toHaveBeenCalledWith(
+        userEmail,
+        undefined,
+        20,
+        0,
+        undefined,
+      );
+      expect(result).toBe(response);
+    });
   });
 
   describe('getEmail', () => {
diff --git a/src/modules/email/email.service.ts b/src/modules/email/email.service.ts
index 2f716c7..0ecffa0 100644
--- a/src/modules/email/email.service.ts
+++ b/src/modules/email/email.service.ts
@@ -23,7 +23,7 @@ export class EmailService {
 
   listEmails(
     userEmail: string,
-    mailbox: MailboxType,
+    mailbox: MailboxType | undefined,
     limit: number,
     position: number,
     anchorId?: string,
diff --git a/src/modules/email/email.types.ts b/src/modules/email/email.types.ts
index 39f17d9..3deeee3 100644
--- a/src/modules/email/email.types.ts
+++ b/src/modules/email/email.types.ts
@@ -23,6 +23,7 @@ export interface Mailbox {
 export interface EmailSummary {
   id: string;
   threadId: string;
+  mailboxIds: string[];
   from: EmailAddress[];
   to: EmailAddress[];
   subject: string;
diff --git a/src/modules/email/mail-provider.port.ts b/src/modules/email/mail-provider.port.ts
index 781bddd..fa0387a 100644
--- a/src/modules/email/mail-provider.port.ts
+++ b/src/modules/email/mail-provider.port.ts
@@ -11,7 +11,7 @@ export abstract class MailProvider {
   abstract getMailboxes(userEmail: string): Promise<Mailbox[]>;
   abstract listEmails(
     userEmail: string,
-    mailbox: MailboxType,
+    mailbox: MailboxType | undefined,
     limit: number,
     position: number,
     anchorId?: string,
diff --git a/src/modules/gateway/gateway.controller.spec.ts b/src/modules/gateway/gateway.controller.spec.ts
index 6c16943..e40fc5e 100644
--- a/src/modules/gateway/gateway.controller.spec.ts
+++ b/src/modules/gateway/gateway.controller.spec.ts
@@ -3,7 +3,6 @@ import { Test, type TestingModule } from '@nestjs/testing';
 import { createMock, type DeepMocked } from '@golevelup/ts-vitest';
 import { GatewayController } from './gateway.controller.js';
 import { AccountService } from '../account/account.service.js';
-import { DomainRepository } from '../account/repositories/domain.repository.js';
 import { MailAccount } from '../account/domain/mail-account.domain.js';
 import { MailDomain } from '../account/domain/mail-domain.domain.js';
 import {
@@ -16,7 +15,6 @@ import { v4 } from 'uuid';
 describe('GatewayController', () => {
   let controller: GatewayController;
   let accountService: DeepMocked<AccountService>;
-  let domains: DeepMocked<DomainRepository>;
 
   beforeEach(async () => {
     const module: TestingModule = await Test.createTestingModule({
@@ -27,7 +25,6 @@ describe('GatewayController', () => {
 
     controller = module.get(GatewayController);
     accountService = module.get(AccountService);
-    domains = module.get(DomainRepository);
   });
 
   describe('provisionAccount', () => {
@@ -74,7 +71,7 @@ describe('GatewayController', () => {
         MailDomain.build(newMailDomainAttributes({ domain: 'internxt.com' })),
         MailDomain.build(newMailDomainAttributes({ domain: 'internxt.me' })),
       ];
-      domains.findAllActive.mockResolvedValue(domainList);
+      accountService.listActiveDomains.mockResolvedValue(domainList);
 
       const result = await controller.listDomains();
 
@@ -85,7 +82,7 @@ describe('GatewayController', () => {
     });
 
     it('when no active domains, then returns empty array', async () => {
-      domains.findAllActive.mockResolvedValue([]);
+      accountService.listActiveDomains.mockResolvedValue([]);
 
       const result = await controller.listDomains();
 
diff --git a/src/modules/gateway/gateway.controller.ts b/src/modules/gateway/gateway.controller.ts
index a8bf68d..18cab11 100644
--- a/src/modules/gateway/gateway.controller.ts
+++ b/src/modules/gateway/gateway.controller.ts
@@ -12,7 +12,6 @@ import {
 import { ApiBearerAuth, ApiOperation, ApiTags } from '@nestjs/swagger';
 import { Public } from '../auth/decorators/public.decorator.js';
 import { AccountService } from '../account/account.service.js';
-import { DomainRepository } from '../account/repositories/domain.repository.js';
 import { GatewayAuthGuard } from './gateway.guard.js';
 import { ProvisionAccountRequestDto } from './gateway.dto.js';
 
@@ -24,10 +23,7 @@ import { ProvisionAccountRequestDto } from './gateway.dto.js';
 export class GatewayController {
   private readonly logger = new Logger(GatewayController.name);
 
-  constructor(
-    private readonly accountService: AccountService,
-    private readonly domains: DomainRepository,
-  ) {}
+  constructor(private readonly accountService: AccountService) {}
 
   @Post('accounts')
   @HttpCode(HttpStatus.CREATED)
@@ -58,7 +54,7 @@ export class GatewayController {
     summary: 'List available mail domains (called by the auth service)',
   })
   async listDomains() {
-    const activeDomains = await this.domains.findAllActive();
+    const activeDomains = await this.accountService.listActiveDomains();
     return activeDomains.map((d) => ({ domain: d.domain }));
   }
 
diff --git a/src/modules/infrastructure/jmap/jmap-mail.mapper.ts b/src/modules/infrastructure/jmap/jmap-mail.mapper.ts
index 47c6749..345d491 100644
--- a/src/modules/infrastructure/jmap/jmap-mail.mapper.ts
+++ b/src/modules/infrastructure/jmap/jmap-mail.mapper.ts
@@ -57,6 +57,7 @@ export function mapJmapEmailToSummary(e: JmapEmail): EmailSummary {
   return {
     id: e.id,
     threadId: e.threadId,
+    mailboxIds: Object.keys(e.mailboxIds),
     from: e.from ?? [],
     to: e.to ?? [],
     subject: e.subject ?? '',
diff --git a/src/modules/infrastructure/jmap/jmap-mail.provider.spec.ts b/src/modules/infrastructure/jmap/jmap-mail.provider.spec.ts
index 8671815..d6f6186 100644
--- a/src/modules/infrastructure/jmap/jmap-mail.provider.spec.ts
+++ b/src/modules/infrastructure/jmap/jmap-mail.provider.spec.ts
@@ -69,7 +69,31 @@ describe('JmapMailProvider', () => {
   });
 
   describe('listEmails', () => {
-    it('When called, then it returns email summaries and total count', async () => {
+    it('when called without mailbox, then returns all email summaries', async () => {
+      const jmapEmails = [newJmapEmail(), newJmapEmail()];
+
+      jmapService.request.mockResolvedValueOnce(
+        jmapMultiResponse(
+          { ids: jmapEmails.map((e) => e.id), total: 42 },
+          { list: jmapEmails },
+        ),
+      );
+
+      const result = await provider.listEmails(
+        'user@test.com',
+        undefined,
+        20,
+        0,
+      );
+
+      expect(result.emails).toHaveLength(2);
+      expect(result.total).toBe(42);
+      expect(result.emails[0]!.mailboxIds).toEqual(
+        Object.keys(jmapEmails[0]!.mailboxIds),
+      );
+    });
+
+    it('when called with a mailbox, then filters by that mailbox', async () => {
       const inboxMailbox = newJmapMailbox({ role: 'inbox' });
       const jmapEmails = [newJmapEmail(), newJmapEmail()];
 
@@ -88,6 +112,48 @@ describe('JmapMailProvider', () => {
       expect(result.emails).toHaveLength(2);
       expect(result.total).toBe(42);
     });
+
+    it('when result count equals limit, then hasMoreMails is true with nextAnchor', async () => {
+      const jmapEmails = [newJmapEmail(), newJmapEmail()];
+
+      jmapService.request.mockResolvedValueOnce(
+        jmapMultiResponse(
+          { ids: jmapEmails.map((e) => e.id), total: 10 },
+          { list: jmapEmails },
+        ),
+      );
+
+      const result = await provider.listEmails(
+        'user@test.com',
+        undefined,
+        2,
+        0,
+      );
+
+      expect(result.hasMoreMails).toBe(true);
+      expect(result.nextAnchor).toBe(jmapEmails[1]!.id);
+    });
+
+    it('when result count is less than limit, then hasMoreMails is false', async () => {
+      const jmapEmails = [newJmapEmail()];
+
+      jmapService.request.mockResolvedValueOnce(
+        jmapMultiResponse(
+          { ids: jmapEmails.map((e) => e.id), total: 1 },
+          { list: jmapEmails },
+        ),
+      );
+
+      const result = await provider.listEmails(
+        'user@test.com',
+        undefined,
+        20,
+        0,
+      );
+
+      expect(result.hasMoreMails).toBe(false);
+      expect(result.nextAnchor).toBeUndefined();
+    });
   });
 
   describe('getEmail', () => {
diff --git a/src/modules/infrastructure/jmap/jmap-mail.provider.ts b/src/modules/infrastructure/jmap/jmap-mail.provider.ts
index 3943a9c..3a5baa1 100644
--- a/src/modules/infrastructure/jmap/jmap-mail.provider.ts
+++ b/src/modules/infrastructure/jmap/jmap-mail.provider.ts
@@ -87,24 +87,42 @@ export class JmapMailProvider extends MailProvider {
 
   async listEmails(
     userEmail: string,
-    mailbox: MailboxType,
+    mailbox: MailboxType | undefined,
     limit: number,
     position: number,
     anchorId?: string,
   ): Promise<EmailListResponse> {
-    const [accountId, mailboxId] = await Promise.all([
-      this.jmap.getPrimaryAccountId(userEmail),
-      this.resolveMailboxId(userEmail, mailbox),
-    ]);
+    const accountId = await this.jmap.getPrimaryAccountId(userEmail);
+
+    if (!mailbox) {
+      return this.queryEmails(userEmail, accountId, limit, position, anchorId);
+    }
+
+    const mailboxId = await this.resolveMailboxId(userEmail, mailbox);
+    return this.queryEmails(userEmail, accountId, limit, position, anchorId, {
+      inMailbox: mailboxId,
+    });
+  }
 
+  private async queryEmails(
+    userEmail: string,
+    accountId: string,
+    limit: number,
+    position: number,
+    anchorId?: string,
+    filter?: Record<string, unknown>,
+  ): Promise<EmailListResponse> {
     const queryParams: Record<string, unknown> = {
       accountId,
-      filter: { inMailbox: mailboxId },
       sort: [{ property: 'receivedAt', isAscending: false }],
       limit,
       calculateTotal: true,
     };
 
+    if (filter) {
+      queryParams.filter = filter;
+    }
+
     if (anchorId) {
       queryParams.anchor = anchorId;
       queryParams.anchorOffset = 1;
@@ -130,15 +148,13 @@ export class JmapMailProvider extends MailProvider {
       .methodResponses[1]![1] as JmapGetResponse<JmapEmail>;
 
     const emails = getResult.list.map(mapJmapEmailToSummary);
-
-    const nextAnchor = emails.length ? emails.at(-1)?.id : undefined;
     const hasMoreEmails = emails.length >= limit;
 
     return {
       emails,
       total: queryResult.total ?? 0,
       hasMoreMails: hasMoreEmails,
-      nextAnchor: hasMoreEmails ? nextAnchor : undefined,
+      nextAnchor: hasMoreEmails ? emails.at(-1)?.id : undefined,
     };
   }
 
diff --git a/test/fixtures.ts b/test/fixtures.ts
index 7dbbbd1..89f7cc1 100644
--- a/test/fixtures.ts
+++ b/test/fixtures.ts
@@ -90,6 +90,7 @@ export function newEmailSummary(attrs?: Partial<EmailSummary>): EmailSummary {
   return {
     id: randomId(),
     threadId: randomId(),
+    mailboxIds: [randomId()],
     from: [newEmailAddress()],
     to: [newEmailAddress()],
     subject: random.sentence({ words: 5 }),