diff --git a/Dockerfile b/Dockerfile
index 49d9fb5..9d096b9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@ EXPOSE 3333
 WORKDIR /app
 ADD package.json yarn.lock /app/
 RUN yarn install --frozen-lockfile
-ADD app.js cert.js /app/
+ADD *.js /app/
 ADD public /app/public
 RUN mkdir -p /root/.config
 ENTRYPOINT yarn start
diff --git a/README.md b/README.md
index 47c8536..f112346 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,22 @@ After you have installed all dependencies you can now run the app.
 Run `npm start` to start a local server.
 The port will be displayed to you as `http://0.0.0.0:3333` (or if you prefer IPv6, if you're using `express` server, then it's `http://[::1]:3333/`).
 
+## Initial users
+
+Adding a JSON file with the following layout will populate the users store when starting:
+
+```json
+{
+  "email@test.com": {
+    "given_name": "name",
+    "family_name": "family",
+    "user_id": "id"
+  }
+}
+```
+
+By default `./users.json` will be read but this can be overridden by setting the environment variable `USERS_FILE`.
+
 ## API Documentation
 
 ### `GET` /token/:username
diff --git a/app.js b/app.js
index c692d6e..d72ad54 100644
--- a/app.js
+++ b/app.js
@@ -10,6 +10,7 @@ const cors = require('cors')
 const bodyParser = require('body-parser')
 const favicon = require('serve-favicon')
 const cert = require('./cert')
+const initialUsers = require('./users')
 
 let issuer = process.env.ISSUER || 'localhost:3333'
 let jwksOrigin = `https://${issuer}/`
@@ -22,8 +23,7 @@ const emailCustomClaim =
 const debug = Debug('app')
 
 let { privateKey, certDer, thumbprint, exponent, modulus } = cert(jwksOrigin)
-
-const users = {}
+const users = initialUsers(process.env.USERS_FILE || './users.json')
 const sessions = {}
 const challenges = {}
 
@@ -356,24 +356,22 @@ app.post('/issuer', (req, res) => {
 
 app.get('/api/v2/users-by-email', (req, res) => {
   const email = req.query.email
-
+  console.log('users', users)
   const user = users[email]
   if (user === undefined) {
     res.json([])
   } else {
-    res.json([
-      user
-    ])
+    res.json([user])
   }
 })
 
 app.post('/api/v2/users', (req, res) => {
   const email = req.body.email
   users[email] = {
-    "email": email,
-    "given_name": "Given",
-    "family_name": "Last",
-    "user_id": email,
+    email: email,
+    given_name: 'Given',
+    family_name: 'Last',
+    user_id: email
   }
   res.json({
     user_id: `auth0|${email}`
diff --git a/users.js b/users.js
new file mode 100644
index 0000000..dacde00
--- /dev/null
+++ b/users.js
@@ -0,0 +1,18 @@
+const fs = require('fs')
+
+const setup = (usersFile) => {
+  let users = {}
+  if (fs.existsSync(usersFile)) {
+    console.log(`initial users file "${usersFile}" exists, reading`)
+    const read = fs.readFileSync(usersFile, { encoding: 'utf8', flag: 'r' })
+    users = JSON.parse(read)
+    for (let key of Object.keys(users)) {
+      users[key] = { ...users[key], email: key }
+    }
+    console.log('users:', users)
+  } else {
+    console.log(`initial users file "${usersFile}" missing`)
+  }
+  return users
+}
+module.exports = setup