diff --git a/server/index.js b/server/index.js
index 235c910..85b2052 100644
--- a/server/index.js
+++ b/server/index.js
@@ -15,7 +15,7 @@ if (process.env.DEBUG || process.env.CROWDFUNDING_SITE_DEBUG) {
   DEBUG = false
 }
 
-if (DEBUG) console.log('Starting website in debug mode')
+if (DEBUG) console.log('Loading website in debug mode')
 
 // set up secret key
 let secretKey
@@ -31,6 +31,11 @@ if (process.env.CROWDFUNDING_SITE_SECRET_KEY) {
   }
 }
 
+// helper function to make the serialiser
+function makeSerialiser(value) {
+  return URLSafeTimedSerializer(secretKey, {salt: value})
+}
+
 // set up nodemailer (if configured)
 let mailer
 let emailFrom
@@ -490,7 +495,7 @@ router.post('/pledge', async (req, res) => {
   }
 
   // generate verification link
-  let serialiser = URLSafeTimedSerializer(secretKey, pledge.get('email'))
+  let serialiser = makeSerialiser(pledge.get('email'))
   let verificationLink = `${req.protocol}://${req.hostname}/verify?email=${encodeURIComponent(pledge.get('email'))}&key=${encodeURIComponent(serialiser.dumps(pledge.get('amount')))}`
 
   // send out the email, along with existing pledge deets
@@ -528,7 +533,7 @@ router.get('/verify', async (req, res) => {
   if (DEBUG) console.debug('Validating pledge:', req.query)
 
   // unpack verification link (unless it's expired)
-  let serialiser = URLSafeTimedSerializer(secretKey, req.query.email)
+  let serialiser = makeSerialiser(req.query.email)
   let amount
 
   try {
@@ -746,4 +751,5 @@ module.exports = {
   Pledge,
   UnverifiedPledge,
   router,
+  makeSerialiser,
 }