diff --git a/browserid/lib/wsapi.js b/browserid/lib/wsapi.js
index 1bee8bc7d28e2519a130573337b4267ac3f0c348..20d8b4de5b15a7d01d2b9f78be0b61a3a6d4d628 100644
--- a/browserid/lib/wsapi.js
+++ b/browserid/lib/wsapi.js
@@ -311,9 +311,23 @@ function setup(app) {
   });
 
   app.post('/wsapi/sync_emails', checkAuthed, function(req,resp) {
-    var emails = req.body.emails;
+    // validate that the post body contains an object with an .emails
+    // property that is an array of strings.
+    var valid = true;
+    try {
+      req.body.emails = JSON.parse(req.body.emails);
+      Object.keys(req.body.emails).forEach(function(k) {
+        if (typeof req.body.emails[k] !== 'string') {
+          throw "bogus value for key " + k;
+        }
+      });
+    } catch (e) {
+      logger.warn("invalid request to sync_emails: " + e);
+      return httputils.badRequest(resp, "sync_emails requires a JSON formatted 'emails' " +
+                                  "post argument");
+    }
 
-    db.getSyncResponse(req.session.authenticatedUser, emails, function(err, syncResponse) {
+    db.getSyncResponse(req.session.authenticatedUser, req.body.emails, function(err, syncResponse) {
       if (err) httputils.serverError(resp, err);
       else resp.json(syncResponse);
     });
diff --git a/browserid/tests/sync-emails-wsapi-test.js b/browserid/tests/sync-emails-wsapi-test.js
new file mode 100755
index 0000000000000000000000000000000000000000..c3651df59ac8dd879d2d8ee6230c4cadd0828805
--- /dev/null
+++ b/browserid/tests/sync-emails-wsapi-test.js
@@ -0,0 +1,156 @@
+#!/usr/bin/env node
+
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla BrowserID.
+ *
+ * The Initial Developer of the Original Code is Mozilla.
+ * Portions created by the Initial Developer are Copyright (C) 2011
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+require('./lib/test_env.js');
+
+const assert = require('assert'),
+vows = require('vows'),
+start_stop = require('./lib/start-stop.js'),
+wsapi = require('./lib/wsapi.js'),
+email = require('../lib/email.js');
+
+var suite = vows.describe('forgotten-email');
+
+// disable vows (often flakey?) async error behavior
+suite.options.error = false;
+
+start_stop.addStartupBatches(suite);
+
+// ever time a new token is sent out, let's update the global
+// var 'token'
+var token = undefined;
+email.setInterceptor(function(email, site, secret) { token = secret; });
+
+// create a new account via the api with (first address)
+suite.addBatch({
+  "stage an account": {
+    topic: wsapi.post('/wsapi/stage_user', {
+      email: 'syncer@somehost.com',
+      pass: 'fakepass',
+      pubkey: 'fakekey',
+      site:'fakesite.com'
+    }),
+    "yields a sane token": function(r, err) {
+      assert.strictEqual(typeof token, 'string');
+    }
+  }
+});
+
+suite.addBatch({
+  "verifying account ownership": {
+    topic: function() {
+      wsapi.get('/wsapi/prove_email_ownership', { token: token }).call(this);
+    },
+    "works": function(r, err) {
+      assert.equal(r.code, 200);
+      assert.strictEqual(true, JSON.parse(r.body));
+    }
+  }
+});
+
+suite.addBatch({
+  "calling registration_status after a registration is complete": {
+    topic: wsapi.get("/wsapi/registration_status"),
+    "yields a HTTP 200": function (r, err) {
+      assert.strictEqual(r.code, 200);
+    },
+    "returns a json encoded string - `complete`": function (r, err) {
+      assert.strictEqual(JSON.parse(r.body), "complete");
+    }
+  }
+});
+
+suite.addBatch({
+  "the sync emails API invoked without a proper argument": {
+    topic: wsapi.post('/wsapi/sync_emails', {}),
+    "fails with HTTP 400" : function(r, err) {
+      assert.strictEqual(r.code, 400);
+    }
+  },
+  "the sync emails API invoked with a proper argument": {  
+    topic: wsapi.post('/wsapi/sync_emails', { emails: '{}' }),
+    "returns a response with a proper content-type" : function(r, err) {
+      assert.strictEqual(r.code, 200);
+      assert.strictEqual(r.headers['content-type'], 'application/json; charset=utf-8');
+    }
+  },
+  "the sync emails API invoked without a empty emails argument": {  
+    topic: wsapi.post('/wsapi/sync_emails', { emails: undefined }),
+    "returns a 400" : function(r, err) {
+      assert.strictEqual(r.code, 400);
+    }
+  },
+  "the sync emails API invoked without malformed JSON in emails argument": {  
+    topic: wsapi.post('/wsapi/sync_emails', { emails: '{ "foo@bar.com": "fakekey" '}),
+    "returns a 400" : function(r, err) {
+      assert.strictEqual(r.code, 400);
+    }
+  },
+  "syncing emails without providing anything": {
+    topic: wsapi.post('/wsapi/sync_emails', {emails: '{}'}),
+    "should tell us to refresh keys for exisitng accounts" : function(r, err) {
+      assert.strictEqual(r.code, 200);
+      r = JSON.parse(r.body);
+      assert.strictEqual(typeof r, 'object');
+      assert.isTrue(Array.isArray(r.unknown_emails));
+      assert.isTrue(Array.isArray(r.key_refresh));
+      assert.strictEqual(r.unknown_emails.length, 0);
+      assert.strictEqual(r.key_refresh.length, 1);
+    }
+  },
+  "syncing emails with an unknown email address": {
+    topic: wsapi.post('/wsapi/sync_emails', {emails: '{ "foo@bar.com": "fake" }'}),
+    "should tell us to refresh keys for exisitng accounts" : function(r, err) {
+      assert.strictEqual(r.code, 200);
+      r = JSON.parse(r.body);
+      assert.strictEqual(typeof r, 'object');
+      assert.isTrue(Array.isArray(r.unknown_emails));
+      assert.isTrue(Array.isArray(r.key_refresh));
+      assert.strictEqual(r.unknown_emails.length, 1);
+      assert.strictEqual(r.unknown_emails[0], 'foo@bar.com');
+      assert.strictEqual(r.key_refresh.length, 1);
+      assert.strictEqual(r.key_refresh[0], 'syncer@somehost.com');
+    }
+  }
+  // NOTE: db-test has more thorough tests of the algorithm behind the sync_emails API
+});
+
+start_stop.addShutdownBatches(suite);
+
+// run or export the suite.
+if (process.argv[1] === __filename) suite.run();
+else suite.export(module);