diff --git a/packages/backend/server/src/modules/quota/storage.ts b/packages/backend/server/src/modules/quota/storage.ts
index f754c6576c..dde3620626 100644
--- a/packages/backend/server/src/modules/quota/storage.ts
+++ b/packages/backend/server/src/modules/quota/storage.ts
@@ -22,6 +22,8 @@ export class QuotaManagementService {
       expiredAt: quota.expiredAt,
       blobLimit: quota.feature.blobLimit,
       storageQuota: quota.feature.storageQuota,
+      historyPeriod: quota.feature.historyPeriod,
+      memberLimit: quota.feature.memberLimit,
     };
   }
 
diff --git a/packages/backend/server/src/modules/workspaces/resolvers/workspace.ts b/packages/backend/server/src/modules/workspaces/resolvers/workspace.ts
index ad3208b555..abd7a9c522 100644
--- a/packages/backend/server/src/modules/workspaces/resolvers/workspace.ts
+++ b/packages/backend/server/src/modules/workspaces/resolvers/workspace.ts
@@ -1,5 +1,6 @@
 import {
   ForbiddenException,
+  HttpStatus,
   InternalServerErrorException,
   Logger,
   NotFoundException,
@@ -16,6 +17,7 @@ import {
 } from '@nestjs/graphql';
 import type { User } from '@prisma/client';
 import { getStreamAsBuffer } from 'get-stream';
+import { GraphQLError } from 'graphql';
 import GraphQLUpload from 'graphql-upload/GraphQLUpload.mjs';
 import { applyUpdate, Doc } from 'yjs';
 
@@ -26,6 +28,7 @@ import type { FileUpload } from '../../../types';
 import { Auth, CurrentUser, Public } from '../../auth';
 import { MailService } from '../../auth/mailer';
 import { AuthService } from '../../auth/service';
+import { QuotaManagementService } from '../../quota';
 import { WorkspaceBlobStorage } from '../../storage';
 import { UsersService, UserType } from '../../users';
 import { PermissionService } from '../permission';
@@ -54,6 +57,7 @@ export class WorkspaceResolver {
     private readonly mailer: MailService,
     private readonly prisma: PrismaService,
     private readonly permissions: PermissionService,
+    private readonly quota: QuotaManagementService,
     private readonly users: UsersService,
     private readonly event: EventEmitter,
     private readonly blobStorage: WorkspaceBlobStorage
@@ -321,8 +325,23 @@ export class WorkspaceResolver {
       throw new ForbiddenException('Cannot change owner');
     }
 
-    const target = await this.users.findUserByEmail(email);
+    // member limit check
+    const [memberCount, quota] = await Promise.all([
+      this.prisma.workspaceUserPermission.count({
+        where: { workspaceId },
+      }),
+      this.quota.getUserQuota(user.id),
+    ]);
+    if (memberCount >= quota.memberLimit) {
+      throw new GraphQLError('Workspace member limit reached', {
+        extensions: {
+          status: HttpStatus[HttpStatus.PAYLOAD_TOO_LARGE],
+          code: HttpStatus.PAYLOAD_TOO_LARGE,
+        },
+      });
+    }
 
+    let target = await this.users.findUserByEmail(email);
     if (target) {
       const originRecord = await this.prisma.workspaceUserPermission.findFirst({
         where: {
@@ -330,94 +349,52 @@ export class WorkspaceResolver {
           userId: target.id,
         },
       });
-
-      if (originRecord) {
-        return originRecord.id;
-      }
-
-      const inviteId = await this.permissions.grant(
-        workspaceId,
-        target.id,
-        permission
-      );
-      if (sendInviteMail) {
-        const inviteInfo = await this.getInviteInfo(inviteId);
-
-        try {
-          await this.mailer.sendInviteEmail(email, inviteId, {
-            workspace: {
-              id: inviteInfo.workspace.id,
-              name: inviteInfo.workspace.name,
-              avatar: inviteInfo.workspace.avatar,
-            },
-            user: {
-              avatar: inviteInfo.user?.avatarUrl || '',
-              name: inviteInfo.user?.name || '',
-            },
-          });
-        } catch (e) {
-          const ret = await this.permissions.revokeWorkspace(
-            workspaceId,
-            target.id
-          );
-
-          if (!ret) {
-            this.logger.fatal(
-              `failed to send ${workspaceId} invite email to ${email} and failed to revoke permission: ${inviteId}, ${e}`
-            );
-          } else {
-            this.logger.warn(
-              `failed to send ${workspaceId} invite email to ${email}, but successfully revoked permission: ${e}`
-            );
-          }
-
-          return new InternalServerErrorException(e);
-        }
-      }
-      return inviteId;
+      // only invite if the user is not already in the workspace
+      if (originRecord) return originRecord.id;
     } else {
-      const user = await this.auth.createAnonymousUser(email);
-      const inviteId = await this.permissions.grant(
-        workspaceId,
-        user.id,
-        permission
-      );
-      if (sendInviteMail) {
-        const inviteInfo = await this.getInviteInfo(inviteId);
-
-        try {
-          await this.mailer.sendInviteEmail(email, inviteId, {
-            workspace: {
-              id: inviteInfo.workspace.id,
-              name: inviteInfo.workspace.name,
-              avatar: inviteInfo.workspace.avatar,
-            },
-            user: {
-              avatar: inviteInfo.user?.avatarUrl || '',
-              name: inviteInfo.user?.name || '',
-            },
-          });
-        } catch (e) {
-          const ret = await this.permissions.revokeWorkspace(
-            workspaceId,
-            user.id
-          );
-
-          if (!ret) {
-            this.logger.fatal(
-              `failed to send ${workspaceId} invite email to ${email} and failed to revoke permission: ${inviteId}, ${e}`
-            );
-          } else {
-            this.logger.warn(
-              `failed to send ${workspaceId} invite email to ${email}, but successfully revoked permission: ${e}`
-            );
-          }
-
-          return new InternalServerErrorException(e);
-        }
-      }
-      return inviteId;
+      target = await this.auth.createAnonymousUser(email);
     }
+
+    const inviteId = await this.permissions.grant(
+      workspaceId,
+      target.id,
+      permission
+    );
+    if (sendInviteMail) {
+      const inviteInfo = await this.getInviteInfo(inviteId);
+
+      try {
+        await this.mailer.sendInviteEmail(email, inviteId, {
+          workspace: {
+            id: inviteInfo.workspace.id,
+            name: inviteInfo.workspace.name,
+            avatar: inviteInfo.workspace.avatar,
+          },
+          user: {
+            avatar: inviteInfo.user?.avatarUrl || '',
+            name: inviteInfo.user?.name || '',
+          },
+        });
+      } catch (e) {
+        const ret = await this.permissions.revokeWorkspace(
+          workspaceId,
+          target.id
+        );
+
+        if (!ret) {
+          this.logger.fatal(
+            `failed to send ${workspaceId} invite email to ${email} and failed to revoke permission: ${inviteId}, ${e}`
+          );
+        } else {
+          this.logger.warn(
+            `failed to send ${workspaceId} invite email to ${email}, but successfully revoked permission: ${e}`
+          );
+        }
+
+        return new InternalServerErrorException(e);
+      }
+    }
+    return inviteId;
   }
 
   @Throttle({
diff --git a/packages/backend/server/tests/mailer.spec.ts b/packages/backend/server/tests/mailer.spec.ts
index 023cfdf35d..e25355bf16 100644
--- a/packages/backend/server/tests/mailer.spec.ts
+++ b/packages/backend/server/tests/mailer.spec.ts
@@ -9,7 +9,8 @@ import graphqlUploadExpress from 'graphql-upload/graphqlUploadExpress.mjs';
 
 import { AppModule } from '../src/app';
 import { MailService } from '../src/modules/auth/mailer';
-import { FeatureManagementService } from '../src/modules/features';
+import { FeatureKind, FeatureManagementService } from '../src/modules/features';
+import { Quotas } from '../src/modules/quota';
 import { PrismaService } from '../src/prisma';
 import { createWorkspace, getInviteInfo, inviteUser, signUp } from './utils';
 
@@ -88,6 +89,32 @@ const FakePrisma = {
       },
     };
   },
+  get features() {
+    return {
+      async findFirst() {
+        return {
+          id: 1,
+          type: FeatureKind.Quota,
+          feature: Quotas[0].feature,
+          configs: Quotas[0].configs,
+          version: Quotas[0].version,
+          createdAt: new Date(),
+        };
+      },
+    };
+  },
+  get userFeatures() {
+    return {
+      async findFirst() {
+        return {
+          createdAt: new Date(),
+          featureId: 1,
+          reason: '',
+          expiredAt: null,
+        };
+      },
+    };
+  },
 };
 
 const test = ava as TestFn<{