diff --git a/packages/backend-core/tests/core/utilities/structures/users.ts b/packages/backend-core/tests/core/utilities/structures/users.ts
index 66d23696e0..68ee29686c 100644
--- a/packages/backend-core/tests/core/utilities/structures/users.ts
+++ b/packages/backend-core/tests/core/utilities/structures/users.ts
@@ -12,7 +12,7 @@ import { generator } from "./generator"
 import { tenant } from "."
 
 export const newEmail = () => {
-  return `${uuid()}@test.com`
+  return `${uuid()}@example.com`
 }
 
 export const user = (userProps?: Partial<Omit<User, "userId">>): User => {
diff --git a/packages/worker/src/api/controllers/global/users.ts b/packages/worker/src/api/controllers/global/users.ts
index de1a605890..1f4168c00b 100644
--- a/packages/worker/src/api/controllers/global/users.ts
+++ b/packages/worker/src/api/controllers/global/users.ts
@@ -1,5 +1,6 @@
 import {
-  checkInviteCode,
+  getInviteCode,
+  deleteInviteCode,
   getInviteCodes,
   updateInviteCode,
 } from "../../../utilities/redis"
@@ -336,10 +337,11 @@ export const checkInvite = async (ctx: any) => {
   const { code } = ctx.params
   let invite
   try {
-    invite = await checkInviteCode(code, false)
+    invite = await getInviteCode(code)
   } catch (e) {
     console.warn("Error getting invite from code", e)
     ctx.throw(400, "There was a problem with the invite")
+    return
   }
   ctx.body = {
     email: invite.email,
@@ -365,12 +367,10 @@ export const updateInvite = async (ctx: any) => {
 
   let invite
   try {
-    invite = await checkInviteCode(code, false)
-    if (!invite) {
-      throw new Error("The invite could not be retrieved")
-    }
+    invite = await getInviteCode(code)
   } catch (e) {
     ctx.throw(400, "There was a problem with the invite")
+    return
   }
 
   let updated = {
@@ -405,7 +405,8 @@ export const inviteAccept = async (
   const { inviteCode, password, firstName, lastName } = ctx.request.body
   try {
     // info is an extension of the user object that was stored by global
-    const { email, info }: any = await checkInviteCode(inviteCode)
+    const { email, info }: any = await getInviteCode(inviteCode)
+    await deleteInviteCode(inviteCode)
     const user = await tenancy.doInTenant(info.tenantId, async () => {
       let request: any = {
         firstName,
diff --git a/packages/worker/src/api/routes/global/tests/users.spec.ts b/packages/worker/src/api/routes/global/tests/users.spec.ts
index 846b98a7ae..adcbca9d29 100644
--- a/packages/worker/src/api/routes/global/tests/users.spec.ts
+++ b/packages/worker/src/api/routes/global/tests/users.spec.ts
@@ -1,11 +1,12 @@
 import { InviteUsersResponse, User } from "@budibase/types"
 
-jest.mock("nodemailer")
 import { TestConfiguration, mocks, structures } from "../../../../tests"
-const sendMailMock = mocks.email.mock()
 import { events, tenancy, accounts as _accounts } from "@budibase/backend-core"
 import * as userSdk from "../../../../sdk/users"
 
+jest.mock("nodemailer")
+const sendMailMock = mocks.email.mock()
+
 const accounts = jest.mocked(_accounts)
 
 describe("/api/global/users", () => {
@@ -54,6 +55,22 @@ describe("/api/global/users", () => {
       expect(events.user.invited).toBeCalledTimes(0)
     })
 
+    it("should not invite the same user twice", async () => {
+      const email = structures.users.newEmail()
+      await config.api.users.sendUserInvite(sendMailMock, email)
+
+      const { code, res } = await config.api.users.sendUserInvite(
+        sendMailMock,
+        email,
+        400
+      )
+
+      expect(res.body.message).toBe(`Unavailable`)
+      expect(sendMailMock).toHaveBeenCalledTimes(0)
+      expect(code).toBeUndefined()
+      expect(events.user.invited).toBeCalledTimes(0)
+    })
+
     it("should be able to create new user from invite", async () => {
       const email = structures.users.newEmail()
       const { code } = await config.api.users.sendUserInvite(
diff --git a/packages/worker/src/sdk/auth/auth.ts b/packages/worker/src/sdk/auth/auth.ts
index d989113c3d..e25d34fa5e 100644
--- a/packages/worker/src/sdk/auth/auth.ts
+++ b/packages/worker/src/sdk/auth/auth.ts
@@ -73,7 +73,7 @@ export const reset = async (email: string) => {
  * Perform the user password update if the provided reset code is valid.
  */
 export const resetUpdate = async (resetCode: string, password: string) => {
-  const { userId } = await redis.checkResetPasswordCode(resetCode)
+  const { userId } = await redis.getResetPasswordCode(resetCode)
 
   let user = await userSdk.db.getUser(userId)
   user.password = password
diff --git a/packages/worker/src/sdk/users/users.ts b/packages/worker/src/sdk/users/users.ts
index 230a8fa146..8f04bb1941 100644
--- a/packages/worker/src/sdk/users/users.ts
+++ b/packages/worker/src/sdk/users/users.ts
@@ -2,6 +2,7 @@ import { events, tenancy, users as usersCore } from "@budibase/backend-core"
 import { InviteUsersRequest, InviteUsersResponse } from "@budibase/types"
 import { sendEmail } from "../../utilities/email"
 import { EmailTemplatePurpose } from "../../constants"
+import { getInviteCodes } from "../..//utilities/redis"
 
 export async function invite(
   users: InviteUsersRequest
@@ -14,6 +15,7 @@ export async function invite(
   const matchedEmails = await usersCore.searchExistingEmails(
     users.map(u => u.email)
   )
+  const existingInvites = await getInviteCodes()
   const newUsers = []
 
   // separate duplicates from new users
diff --git a/packages/worker/src/utilities/email.ts b/packages/worker/src/utilities/email.ts
index c5b1d9d8ab..a0c02d335c 100644
--- a/packages/worker/src/utilities/email.ts
+++ b/packages/worker/src/utilities/email.ts
@@ -3,7 +3,7 @@ import { EmailTemplatePurpose, TemplateType } from "../constants"
 import { getTemplateByPurpose, EmailTemplates } from "../constants/templates"
 import { getSettingsTemplateContext } from "./templates"
 import { processString } from "@budibase/string-templates"
-import { getResetPasswordCode, getInviteCode } from "./redis"
+import { createResetPasswordCode, createInviteCode } from "./redis"
 import { User, SendEmailOpts, SMTPInnerConfig } from "@budibase/types"
 import { configs } from "@budibase/backend-core"
 import ical from "ical-generator"
@@ -61,9 +61,9 @@ async function getLinkCode(
 ) {
   switch (purpose) {
     case EmailTemplatePurpose.PASSWORD_RECOVERY:
-      return getResetPasswordCode(user._id!, info)
+      return createResetPasswordCode(user._id!, info)
     case EmailTemplatePurpose.INVITATION:
-      return getInviteCode(email, info)
+      return createInviteCode(email, info)
     default:
       return null
   }
diff --git a/packages/worker/src/utilities/redis.ts b/packages/worker/src/utilities/redis.ts
index 993cdf97ce..9852fb0467 100644
--- a/packages/worker/src/utilities/redis.ts
+++ b/packages/worker/src/utilities/redis.ts
@@ -1,60 +1,24 @@
 import { redis, utils, tenancy } from "@budibase/backend-core"
 import env from "../environment"
 
-function getExpirySecondsForDB(db: string) {
-  switch (db) {
-    case redis.utils.Databases.PW_RESETS:
-      // a hour
-      return 3600
-    case redis.utils.Databases.INVITATIONS:
-      // a week
-      return 604800
-  }
+interface Invite {
+  email: string
+  info: any
 }
 
-let pwResetClient: any, invitationClient: any
-
-function getClient(db: string) {
-  switch (db) {
-    case redis.utils.Databases.PW_RESETS:
-      return pwResetClient
-    case redis.utils.Databases.INVITATIONS:
-      return invitationClient
-  }
+interface InviteWithCode extends Invite {
+  code: string
 }
 
-async function writeACode(db: string, value: any) {
-  const client = await getClient(db)
-  const code = utils.newid()
-  await client.store(code, value, getExpirySecondsForDB(db))
-  return code
+interface PasswordReset {
+  userId: string
+  info: any
 }
 
-async function updateACode(db: string, code: string, value: any) {
-  const client = await getClient(db)
-  await client.store(code, value, getExpirySecondsForDB(db))
-}
-
-/**
- * Given an invite code and invite body, allow the update an existing/valid invite in redis
- * @param inviteCode The invite code for an invite in redis
- * @param value The body of the updated user invitation
- */
-export async function updateInviteCode(inviteCode: string, value: string) {
-  await updateACode(redis.utils.Databases.INVITATIONS, inviteCode, value)
-}
-
-async function getACode(db: string, code: string, deleteCode = true) {
-  const client = await getClient(db)
-  const value = await client.get(code)
-  if (!value) {
-    throw new Error("Invalid code.")
-  }
-  if (deleteCode) {
-    await client.delete(code)
-  }
-  return value
-}
+type RedisDBName =
+  | redis.utils.Databases.PW_RESETS
+  | redis.utils.Databases.INVITATIONS
+let pwResetClient: redis.Client, invitationClient: redis.Client
 
 export async function init() {
   pwResetClient = new redis.Client(redis.utils.Databases.PW_RESETS)
@@ -63,9 +27,6 @@ export async function init() {
   await invitationClient.init()
 }
 
-/**
- * make sure redis connection is closed.
- */
 export async function shutdown() {
   if (pwResetClient) await pwResetClient.finish()
   if (invitationClient) await invitationClient.finish()
@@ -74,6 +35,65 @@ export async function shutdown() {
   console.log("Redis shutdown")
 }
 
+function getExpirySecondsForDB(db: RedisDBName) {
+  switch (db) {
+    case redis.utils.Databases.PW_RESETS:
+      // a hour
+      return 3600
+    case redis.utils.Databases.INVITATIONS:
+      // a week
+      return 604800
+    default:
+      throw new Error(`Unknown redis database: ${db}`)
+  }
+}
+
+function getClient(db: RedisDBName): redis.Client {
+  switch (db) {
+    case redis.utils.Databases.PW_RESETS:
+      return pwResetClient
+    case redis.utils.Databases.INVITATIONS:
+      return invitationClient
+    default:
+      throw new Error(`Unknown redis database: ${db}`)
+  }
+}
+
+async function writeCode(db: RedisDBName, value: Invite | PasswordReset) {
+  const client = getClient(db)
+  const code = utils.newid()
+  await client.store(code, value, getExpirySecondsForDB(db))
+  return code
+}
+
+async function updateCode(db: RedisDBName, code: string, value: any) {
+  const client = getClient(db)
+  await client.store(code, value, getExpirySecondsForDB(db))
+}
+
+/**
+ * Given an invite code and invite body, allow the update an existing/valid invite in redis
+ * @param inviteCode The invite code for an invite in redis
+ * @param value The body of the updated user invitation
+ */
+export async function updateInviteCode(code: string, value: Invite) {
+  await updateCode(redis.utils.Databases.INVITATIONS, code, value)
+}
+
+async function deleteCode(db: RedisDBName, code: string) {
+  const client = getClient(db)
+  await client.delete(code)
+}
+
+async function getCode(db: RedisDBName, code: string) {
+  const client = getClient(db)
+  const value = await client.get(code)
+  if (!value) {
+    throw new Error(`Could not find code: ${code}`)
+  }
+  return value
+}
+
 /**
  * Given a user ID this will store a code (that is returned) for an hour in redis.
  * The user can then return this code for resetting their password (through their reset link).
@@ -81,22 +101,20 @@ export async function shutdown() {
  * @param info Info about the user/the reset process.
  * @return returns the code that was stored to redis.
  */
-export async function getResetPasswordCode(userId: string, info: any) {
-  return writeACode(redis.utils.Databases.PW_RESETS, { userId, info })
+export async function createResetPasswordCode(userId: string, info: any) {
+  return writeCode(redis.utils.Databases.PW_RESETS, { userId, info })
 }
 
 /**
- * Given a reset code this will lookup to redis, check if the code is valid and delete if required.
+ * Given a reset code this will lookup to redis, check if the code is valid.
  * @param resetCode The code provided via the email link.
- * @param deleteCode If the code is used/finished with this will delete it - defaults to true.
  * @return returns the user ID if it is found
  */
-export async function checkResetPasswordCode(
-  resetCode: string,
-  deleteCode = true
-) {
+export async function getResetPasswordCode(
+  code: string
+): Promise<PasswordReset> {
   try {
-    return getACode(redis.utils.Databases.PW_RESETS, resetCode, deleteCode)
+    return getCode(redis.utils.Databases.PW_RESETS, code)
   } catch (err) {
     throw "Provided information is not valid, cannot reset password - please try again."
   }
@@ -108,35 +126,35 @@ export async function checkResetPasswordCode(
  * @param info Information to be carried along with the invitation.
  * @return returns the code that was stored to redis.
  */
-export async function getInviteCode(email: string, info: any) {
-  return writeACode(redis.utils.Databases.INVITATIONS, { email, info })
+export async function createInviteCode(email: string, info: any) {
+  return writeCode(redis.utils.Databases.INVITATIONS, { email, info })
 }
 
 /**
  * Checks that the provided invite code is valid - will return the email address of user that was invited.
  * @param inviteCode the invite code that was provided as part of the link.
- * @param deleteCode whether or not the code should be deleted after retrieval - defaults to true.
  * @return If the code is valid then an email address will be returned.
  */
-export async function checkInviteCode(
-  inviteCode: string,
-  deleteCode: boolean = true
-) {
+export async function getInviteCode(code: string): Promise<Invite> {
   try {
-    return getACode(redis.utils.Databases.INVITATIONS, inviteCode, deleteCode)
+    return getCode(redis.utils.Databases.INVITATIONS, code)
   } catch (err) {
     throw "Invitation is not valid or has expired, please request a new one."
   }
 }
 
+export async function deleteInviteCode(code: string) {
+  return deleteCode(redis.utils.Databases.INVITATIONS, code)
+}
+
 /** 
   Get all currently available user invitations for the current tenant.
 **/
-export async function getInviteCodes() {
-  const client = await getClient(redis.utils.Databases.INVITATIONS)
-  const invites: any[] = await client.scan()
+export async function getInviteCodes(): Promise<InviteWithCode[]> {
+  const client = getClient(redis.utils.Databases.INVITATIONS)
+  const invites: { key: string; value: Invite }[] = await client.scan()
 
-  const results = invites.map(invite => {
+  const results: InviteWithCode[] = invites.map(invite => {
     return {
       ...invite.value,
       code: invite.key,