diff --git a/CHANGES b/CHANGES
index 35ca0c012..d6c867f2c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2240,4 +2240,5 @@
 * Fix bug where renew certs button did not work
 * filemanager: various enhancements
 * sftp: fix rebuild condition
+* app mailbox is now optional
 
diff --git a/migrations/20210317014101-apps-add-enableMailbox.js b/migrations/20210317014101-apps-add-enableMailbox.js
new file mode 100644
index 000000000..6f48a9bc4
--- /dev/null
+++ b/migrations/20210317014101-apps-add-enableMailbox.js
@@ -0,0 +1,16 @@
+'use strict';
+
+exports.up = function(db, callback) {
+    db.runSql('ALTER TABLE apps ADD COLUMN enableMailbox BOOLEAN DEFAULT 1', function (error) {
+        if (error) console.error(error);
+        callback(error);
+    });
+};
+
+exports.down = function(db, callback) {
+    db.runSql('ALTER TABLE apps DROP COLUMN enableMailbox', function (error) {
+        if (error) console.error(error);
+        callback(error);
+    });
+};
+
diff --git a/migrations/schema.sql b/migrations/schema.sql
index e53e2da0f..90a5f145a 100644
--- a/migrations/schema.sql
+++ b/migrations/schema.sql
@@ -79,6 +79,7 @@ CREATE TABLE IF NOT EXISTS apps(
     reverseProxyConfigJson TEXT, // { robotsTxt, csp }
     enableBackup BOOLEAN DEFAULT 1, // misnomer: controls automatic daily backups
     enableAutomaticUpdate BOOLEAN DEFAULT 1,
+    enableMailbox BOOLEAN DEFAULT 1, // whether sendmail addon is enabled
     mailboxName VARCHAR(128), // mailbox of this app
     mailboxDomain VARCHAR(128), // mailbox domain of this apps
     label VARCHAR(128),     // display name
diff --git a/src/appdb.js b/src/appdb.js
index 78671f856..ac56ba646 100644
--- a/src/appdb.js
+++ b/src/appdb.js
@@ -42,7 +42,7 @@ const APPS_FIELDS_PREFIXED = [ 'apps.id', 'apps.appStoreId', 'apps.installationS
     'apps.health', 'apps.containerId', 'apps.manifestJson', 'apps.accessRestrictionJson', 'apps.memoryLimit', 'apps.cpuShares',
     'apps.label', 'apps.tagsJson', 'apps.taskId', 'apps.reverseProxyConfigJson', 'apps.servicesConfigJson',
     'apps.sso', 'apps.debugModeJson', 'apps.enableBackup', 'apps.proxyAuth', 'apps.containerIp',
-    'apps.creationTime', 'apps.updateTime', 'apps.mailboxName', 'apps.mailboxDomain', 'apps.enableAutomaticUpdate',
+    'apps.creationTime', 'apps.updateTime', 'apps.enableMailbox', 'apps.mailboxName', 'apps.mailboxDomain', 'apps.enableAutomaticUpdate',
     'apps.dataDir', 'apps.ts', 'apps.healthTime' ].join(',');
 
 const PORT_BINDINGS_FIELDS = [ 'hostPort', 'type', 'environmentVariable', 'appId' ].join(',');
@@ -86,6 +86,7 @@ function postProcess(result) {
     result.sso = !!result.sso; // make it bool
     result.enableBackup = !!result.enableBackup; // make it bool
     result.enableAutomaticUpdate = !!result.enableAutomaticUpdate; // make it bool
+    result.enableMailbox = !!result.enableMailbox; // make it bool
     result.proxyAuth = !!result.proxyAuth;
 
     assert(result.debugModeJson === null || typeof result.debugModeJson === 'string');
diff --git a/src/apps.js b/src/apps.js
index 807dbd8d1..5b2bd5fcb 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -411,7 +411,7 @@ function removeInternalFields(app) {
         'location', 'domain', 'fqdn', 'mailboxName', 'mailboxDomain',
         'accessRestriction', 'manifest', 'portBindings', 'iconUrl', 'memoryLimit', 'cpuShares',
         'sso', 'debugMode', 'reverseProxyConfig', 'enableBackup', 'creationTime', 'updateTime', 'ts', 'tags',
-        'label', 'alternateDomains', 'aliasDomains', 'env', 'enableAutomaticUpdate', 'dataDir', 'mounts');
+        'label', 'alternateDomains', 'aliasDomains', 'env', 'enableAutomaticUpdate', 'dataDir', 'mounts', 'enableMailbox');
 }
 
 // non-admins can only see these
@@ -1079,13 +1079,18 @@ function setDebugMode(app, debugMode, auditSource, callback) {
     });
 }
 
-function setMailbox(app, mailboxName, mailboxDomain, auditSource, callback) {
+function setMailbox(app, data, auditSource, callback) {
     assert.strictEqual(typeof app, 'object');
-    assert(mailboxName === null || typeof mailboxName === 'string');
-    assert.strictEqual(typeof mailboxDomain, 'string');
+    assert.strictEqual(typeof data, 'object');
     assert.strictEqual(typeof auditSource, 'object');
     assert.strictEqual(typeof callback, 'function');
 
+    const { enable, mailboxDomain } = data;
+    let mailboxName = data.mailboxName;
+    assert.strictEqual(typeof enable, 'boolean');
+    assert(mailboxName === null || typeof mailboxName === 'string');
+    assert.strictEqual(typeof mailboxDomain, 'string');
+
     const appId = app.id;
     let error = checkAppState(app, exports.ISTATE_PENDING_RECREATE_CONTAINER);
     if (error) return callback(error);
@@ -1104,7 +1109,7 @@ function setMailbox(app, mailboxName, mailboxDomain, auditSource, callback) {
 
         const task = {
             args: {},
-            values: { mailboxName, mailboxDomain }
+            values: { enableMailbox: enable, mailboxName, mailboxDomain }
         };
         addTask(appId, exports.ISTATE_PENDING_RECREATE_CONTAINER, task, function (error, result) {
             if (error) return callback(error);
diff --git a/src/routes/apps.js b/src/routes/apps.js
index 7c16b731a..1aabd3c3b 100644
--- a/src/routes/apps.js
+++ b/src/routes/apps.js
@@ -335,10 +335,13 @@ function setMailbox(req, res, next) {
     assert.strictEqual(typeof req.body, 'object');
     assert.strictEqual(typeof req.resource, 'object');
 
-    if (req.body.mailboxName !== null && typeof req.body.mailboxName !== 'string') return next(new HttpError(400, 'mailboxName must be a string'));
-    if (typeof req.body.mailboxDomain !== 'string') return next(new HttpError(400, 'mailboxDomain must be a string'));
+    if (typeof req.body.enable !== 'boolean') return next(new HttpError(400, 'enable must be a boolean'));
+    if (req.body.enable) {
+        if (req.body.mailboxName !== null && typeof req.body.mailboxName !== 'string') return next(new HttpError(400, 'mailboxName must be a string'));
+        if (typeof req.body.mailboxDomain !== 'string') return next(new HttpError(400, 'mailboxDomain must be a string'));
+    }
 
-    apps.setMailbox(req.resource, req.body.mailboxName, req.body.mailboxDomain, auditSource.fromRequest(req), function (error, result) {
+    apps.setMailbox(req.resource, req.body, auditSource.fromRequest(req), function (error, result) {
         if (error) return next(BoxError.toHttpError(error));
 
         next(new HttpSuccess(202, { taskId: result.taskId }));
diff --git a/src/services.js b/src/services.js
index 55462cc20..0cffa84b0 100644
--- a/src/services.js
+++ b/src/services.js
@@ -1070,6 +1070,9 @@ function setupSendMail(app, options, callback) {
 
     debugApp(app, 'Setting up SendMail');
 
+    const disabled = app.manifest.addons.sendmail.optional && !app.enableMailbox;
+    if (disabled) return appdb.setAddonConfig(app.id, 'sendmail', [], callback);
+
     appdb.getAddonConfigByName(app.id, 'sendmail', '%MAIL_SMTP_PASSWORD', function (error, existingPassword) {
         if (error && error.reason !== BoxError.NOT_FOUND) return callback(error);