Arcjet signup form protection combines rate limiting, bot protection, and email
validation to protect your signup forms from abuse.
Configuration
Signup form protection is a combination of the rate
limiting , bot
protection , and email
validation primitives. The
configuration options are the same, but specified in a single rule.
The configuration definition is:
type ProtectSignupOptions = {
rateLimit ?: SlidingWindowRateLimitOptions | SlidingWindowRateLimitOptions [] ;
email ?: EmailOptions | EmailOptions [] ;
The arcjet
client is configured with one protectSignup
rule which take
ProtectSignupOptions
.
Recommended configuration
Our recommended configuration for most signup forms is:
Block emails with invalid syntax, that are from disposable email providers, or
do not have valid MX records configured.
Block clients that we are sure are automated.
Apply a rate limit of 5 submissions per 10 minutes from a single IP address.
This can be configured as follows:
import { protectSignup } from " @arcjet/nest " ;
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
import arcjet , { protectSignup } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
import arcjet , { protectSignup } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
import arcjet , { protectSignup } from " @arcjet/node " ;
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
import arcjet , { protectSignup } from " @arcjet/remix " ;
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
import { env } from " $env/dynamic/private " ;
import arcjet , { protectSignup } from " @arcjet/sveltekit " ;
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
Testing with dry run mode
When you are testing your signup form protection configuration, you can run the
rules in dry run mode first by setting mode
to DRY_RUN
. This will return an
allow decision for every request, but log what the results would have been if
they were in live mode. You can view the results in the Arcjet
dashboard .
Even in dry run mode each rule will still be evaluated, so you can still check
the rule results to see if the email address is valid
or not, or log them to your database.
Pages & Server Actions
Arcjet can be used inside Next.js middleware, API routes, pages, server
components, and server actions. Client components cannot be protected because
they run on the client only.
See the Next.js SDK reference for examples of pages / page
components and server
actions .
Decision
Arcjet provides a single protect
function that is used to execute your
protection rules. This requires a request
argument which is the request
context as passed to the request handler. When configured with a protectSignup
rule it also requires an additional email
prop.
Arcjet can be integrated using a global guard
or per route guards. However these can’t be used for signup protection rules
because you can’t access the decision to handle the form submission. Instead,
you call the protect
function in your route handler. See
bot protection for an example where guards are
used.
This function returns a Promise
that resolves to an
ArcjetDecision
object. This contains the following properties:
id
(string
) - The unique ID for the request. This can be used to look up
the request in the Arcjet dashboard. It is prefixed with req_
for decisions
involving the Arcjet cloud API. For decisions taken locally, the prefix is
lreq_
.
conclusion
(ArcjetConclusion
) - The final conclusion based on evaluating
each of the configured rules. If you wish to accept Arcjet’s recommended
action based on the configured rules then you can use this property.
reason
(ArcjetReason
) - An object containing more detailed
information about the conclusion.
results
(ArcjetRuleResult[]
) - An array of ArcjetRuleResult
objects
containing the results of each rule that was executed.
ip
(ArcjetIpDetails
) - An object containing Arcjet’s analysis of the
client IP address. See the SDK reference for more information.
Accepting our recommended action
The conclusion
property contains the final conclusion based on evaluating each
of the configured rules. The quick start example code above uses this property
to accept Arcjet’s recommended action - display an error to the user if their
email is rejected, otherwise return a 403
error.
You can check if a deny decision was returned by using decision.isDenied()
. To
narrow down the reason to an email validation rule, you can use
decision.reason.isEmail()
.
Checking rule results
You can iterate through the results of each rule:
for ( const result of decision . results ) {
console . log ( " Rule Result " , result ) ;
This could be useful metadata to add to a new user’s record in your database
before you redirect them to the next step in your signup flow.
Custom verification logic
Checking the rule results allows you to use the Arcjet decision as part of your
own verification logic. For example, you could decide to manually verify user
signups that come from IP addresses associated with proxies or Tor, and any
users who sign up with a free email address.
import arcjet , { protectSignup } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY , // Get your site key from https://app.arcjet.com
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
fetch : aj . handler ( async ( req ) => {
// Get email from Bun request body
const formData = await req . formData () ;
const email = formData . get ( " email " ) ?. toString () ?? "" ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return new Response ( " Invalid email " , { status : 400 } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page.
return new Response ( " Forbidden " , { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return new Response ( " Valid email " ) ;
import arcjet , { protectSignup , type ArcjetDecision } from " @arcjet/bun " ;
import { env } from " bun " ;
key : env . ARCJET_KEY ! , // Get your site key from https://app.arcjet.com
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
fetch : aj . handler ( async ( req ) => {
// Get email from Bun request body
const formData = await req . formData () ;
const email = formData . get ( " email " ) ?. toString () ?? "" ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return new Response ( " Invalid email " , { status : 400 } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page.
return new Response ( " Forbidden " , { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return new Response ( " Valid email " ) ;
import arcjet , { protectSignup } from " @arcjet/remix " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function action ( args ) {
// The request body is a FormData object
const formData = await args . request . formData () ;
const email = formData . get ( " email " ) ;
const decision = await aj . protect ( args , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return Response . json ( { error : " Invalid email. " }, { status : 400 } ) ;
return Response . json ( { error : " Forbidden " }, { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
// We don't need to use the decision elsewhere, but you could return it to
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/remix " ;
import type { ActionFunctionArgs } from " @remix-run/node " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function action ( args : ActionFunctionArgs ) {
// The request body is a FormData object
const formData = await args . request . formData () ;
const email = formData . get ( " email " ) as string ;
const decision = await aj . protect ( args , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return Response . json ( { error : " Invalid email. " }, { status : 400 } ) ;
return Response . json ( { error : " Forbidden " }, { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
// We don't need to use the decision elsewhere, but you could return it to
import { env } from " $env/dynamic/private " ;
import arcjet , { protectSignup } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function POST ( event ) {
const { email } = await event . request . json () ;
const decision = await aj . protect ( event , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return error ( 400 , { message : " Invalid email " } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page
return error ( 403 , { message : " Forbidden " } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return json ( { message : " Valid email " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { protectSignup , type ArcjetDecision } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function POST ( event : RequestEvent ) {
const { email } = await event . request . json () ;
const decision = await aj . protect ( event , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return error ( 400 , { message : " Invalid email " } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page
return error ( 403 , { message : " Forbidden " } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return json ( { message : " Valid email " } ) ;
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export default async function handler ( req , res ) {
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return res . status ( 400 ) . json ( {
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return res . status ( 403 ) . json ( {
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function POST ( req : Request ) {
const data = await req . json () ;
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return NextResponse . json (
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/app/building-your-application/routing/route-handlers#redirects
return NextResponse . json ( { message : " Forbidden " }, { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return NextResponse . json ( {
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export default async function handler (
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return res . status ( 400 ) . json ( {
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return res . status ( 403 ) . json ( {
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { protectSignup } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export async function POST ( req ) {
const data = await req . json () ;
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
console . log ( " Arcjet decision: " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return NextResponse . json (
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/app/building-your-application/routing/route-handlers#redirects
return NextResponse . json ( { message : " Forbidden " }, { status : 403 } ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return NextResponse . json ( {
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/node " ;
import express from " express " ;
app . use ( express . urlencoded ( { extended : false } )) ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision ) {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision ) {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
app . post ( " / " , async ( req , res ) => {
const email = req . body . email ;
const decision = await aj . protect ( req , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
// If the email is invalid then return an error message
res . writeHead ( 400 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Invalid email " , reason : decision . reason } ) ,
// We get here if the client is a bot or the rate limit has been exceeded
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello World " , email } )) ;
console . log ( ` Example app listening on port ${ port }` ) ;
import arcjet , { protectSignup , ArcjetDecision } from " @arcjet/node " ;
import express from " express " ;
app . use ( express . urlencoded ( { extended : false } )) ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
app . post ( " / " , async ( req , res ) => {
const email = req . body . email ;
const decision = await aj . protect ( req , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
// If the email is invalid then return an error message
res . writeHead ( 400 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Invalid email " , reason : decision . reason } ) ,
// We get here if the client is a bot or the rate limit has been exceeded
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
res . writeHead ( 200 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { message : " Hello World " , email } )) ;
console . log ( ` Example app listening on port ${ port }` ) ;
import { NoFilesInterceptor } from " @nestjs/platform-express " ;
import { IsNotEmpty } from " class-validator " ;
import type { Request } from " express " ;
// Validation class as described at
// https://docs.nestjs.com/techniques/validation. We're not using the IsEmail
// decorator here because Arcjet handles this for you.
// @ts-ignore: This is a DTO class so ignore that it's not definitely assigned
// This would normally go in your service file e.g.
// src/signup/signup.service.ts
export class SignupService {
private readonly logger = new Logger ( SignupService . name ) ;
signup ( email : string ) : { message : string } {
this . logger . log ( ` Form submission: ${ email }` ) ;
// This would normally go in your controller file e.g.
// src/signup/signup.controller.ts
// If the signup was coming from a proxy or Tor IP address this is suspicious,
// but we don't want to block them. Instead we will require manual verification
function isProxyOrTor ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
( decision . ip . isProxy () || decision . ip . isTor ())
// If the signup email address was from a free provider we want to double check
function isFreeEmail ( decision : ArcjetDecision ) : boolean {
for ( const result of decision . results ) {
if ( result . reason . isEmail () && result . reason . emailTypes . includes ( " FREE " )) {
export class SignupController {
private readonly logger = new Logger ( SignupController . name ) ;
private readonly signupService : SignupService ,
@ Inject ( ARCJET ) private readonly arcjet : ArcjetNest ,
// Implement a form handler following
// https://docs.nestjs.com/techniques/file-upload#no-files. Note this isn't
// compatible with the NestJS Fastify adapter.
@ UseInterceptors ( NoFilesInterceptor ())
async index (@ Req () req : Request , @ Body () body : SignupDto ) {
const decision = await this . arcjet
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [ " CURL " ] , // prevents bots from submitting the form, but allow curl for this example
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 2m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
. protect ( req , { email : body . email } ) ;
this . logger . log ( ` Arcjet: id = ${ decision . id }` ) ;
this . logger . log ( ` Arcjet: decision = ${ decision . conclusion }` ) ;
if ( decision . isDenied ()) {
if ( decision . reason . isBot ()) {
throw new HttpException ( " No bots allowed " , HttpStatus . FORBIDDEN ) ;
} else if ( decision . reason . isRateLimit ()) {
HttpStatus . TOO_MANY_REQUESTS ,
} else if ( decision . reason . isEmail ()) {
this . logger . log ( ` Arcjet: email error = ${ decision . reason . emailTypes }` ) ;
// These are specific errors to help the user, but will also reveal the
// validation to a spammer.
if ( decision . reason . emailTypes . includes ( " INVALID " )) {
message = " email address format is invalid. Is there a typo? " ;
} else if ( decision . reason . emailTypes . includes ( " DISPOSABLE " )) {
message = " we do not allow disposable email addresses. " ;
} else if ( decision . reason . emailTypes . includes ( " NO_MX_RECORDS " )) {
" your email domain does not have an MX record. Is there a typo? " ;
// This is a catch all, but the above should be exhaustive based on the
message = " invalid email. " ;
throw new HttpException ( ` Error: ${ message }` , HttpStatus . BAD_REQUEST ) ;
throw new HttpException ( " Forbidden " , HttpStatus . FORBIDDEN ) ;
// At this point the signup is allowed, but we may want to take additional
const requireAdditionalVerification =
isProxyOrTor ( decision ) || isFreeEmail ( decision ) ;
// User creation code goes here...
return this . signupService . signup ( body . email ) ;
Error handling
Arcjet is designed to fail open so that a service issue or misconfiguration does
not block all requests. The SDK will also time out and fail open after 1000ms
when NODE_ENV
or ARCJET_ENV
is development
and 500ms otherwise. However,
in most cases, the response time will be less than 20-30ms.
If there is an error condition, Arcjet will return an ERROR
conclusion
.
import arcjet , { protectSignup } from " @arcjet/bun " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : Bun . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
fetch : aj . handler ( async ( req ) => {
// Get email from Bun request body
const formData = await req . formData () ;
const email = formData . get ( " email " ) ?. toString () ?? "" ;
console . log ( " Email received: " , email ) ;
const decision = await aj . protect ( req , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
// If the email is invalid then return an error message
return new Response ( " Invalid email " , { status : 400 } ) ;
// We get here if the client is a bot or the rate limit has been exceeded
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello " + email ) ;
import arcjet , { protectSignup } from " @arcjet/bun " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
fetch : aj . handler ( async ( req ) => {
// Get email from Bun request body
const formData = await req . formData () ;
const email = formData . get ( " email " ) ?. toString () ?? "" ;
console . log ( " Email received: " , email ) ;
const decision = await aj . protect ( req , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return new Response("Service unavailable", { status: 503 });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
// If the email is invalid then return an error message
return new Response ( " Invalid email " , { status : 400 } ) ;
// We get here if the client is a bot or the rate limit has been exceeded
return new Response ( " Forbidden " , { status : 403 } ) ;
return new Response ( " Hello " + email ) ;
import arcjet , { protectSignup } from " @arcjet/next " ;
key : process . env . ARCJET_KEY ,
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
export default async function handler ( req , res ) {
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return res.status(503).json({ error: "Service unavailable" });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return res . status ( 400 ) . json ( {
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return res . status ( 403 ) . json ( {
// The form submission is allowed to proceed so do something with it here
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { protectSignup } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ! ,
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
export async function POST ( req : Request ) {
const data = await req . json () ;
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return NextResponse.json({ error: "Service unavailable" }, { status: 503 });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return NextResponse . json (
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return NextResponse . json ( { message : " Forbidden " }, { status : 403 } ) ;
// The form submission is allowed to proceed so do something with it here
return NextResponse . json ( {
import arcjet , { protectSignup } from " @arcjet/next " ;
import type { NextApiRequest , NextApiResponse } from " next " ;
key : process . env . ARCJET_KEY ! ,
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
export default async function handler (
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return res.status(503).json({ error: "Service unavailable" });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return res . status ( 400 ) . json ( {
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return res . status ( 403 ) . json ( {
// The form submission is allowed to proceed so do something with it here
res . status ( 200 ) . json ( { name : " Hello world " } ) ;
import arcjet , { protectSignup } from " @arcjet/next " ;
import { NextResponse } from " next/server " ;
key : process . env . ARCJET_KEY ,
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
export async function POST ( req ) {
const data = await req . json () ;
const email = data . email ;
const decision = await aj . protect ( req , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return NextResponse.json({ error: "Service unavailable" }, { status: 503 });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return NextResponse . json (
message : " Invalid email " ,
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page. See
// https://nextjs.org/docs/pages/building-your-application/data-fetching/forms-and-mutations#redirecting
return NextResponse . json ( { message : " Forbidden " }, { status : 403 } ) ;
// The form submission is allowed to proceed so do something with it here
return NextResponse . json ( {
import arcjet , { protectSignup } from " @arcjet/remix " ;
import type { ActionFunctionArgs } from " @remix-run/node " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
export async function action ( args : ActionFunctionArgs ) {
// The request body is a FormData object
const formData = await args . request . formData () ;
const email = formData . get ( " email " ) as string ;
const decision = await aj . protect ( args , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//res.writeHead(503, { "Content-Type": "application/json" });
//res.end(JSON.stringify({ error: "Service unavailable" }));
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return Response . json ( { error : " Invalid email. " }, { status : 400 } ) ;
return Response . json ( { error : " Forbidden " }, { status : 403 } ) ;
// We don't need to use the decision elsewhere, but you could return it to
import arcjet , { protectSignup } from " @arcjet/remix " ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
export async function action ( args ) {
// The request body is a FormData object
const formData = await args . request . formData () ;
const email = formData . get ( " email " ) ;
const decision = await aj . protect ( args , { email } ) ;
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//res.writeHead(503, { "Content-Type": "application/json" });
//res.end(JSON.stringify({ error: "Service unavailable" }));
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return Response . json ( { error : " Invalid email. " }, { status : 400 } ) ;
return Response . json ( { error : " Forbidden " }, { status : 403 } ) ;
// We don't need to use the decision elsewhere, but you could return it to
import { env } from " $env/dynamic/private " ;
import arcjet , { protectSignup } from " @arcjet/sveltekit " ;
import { error , json , type RequestEvent } from " @sveltejs/kit " ;
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
export async function POST ( event : RequestEvent ) {
const { email } = await event . request . json () ;
const decision = await aj . protect ( event , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return error(503, { message: "Service unavailable" });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return error ( 400 , { message : " Invalid email " } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page
return error ( 403 , { message : " Forbidden " } ) ;
// User creation code goes here...
return json ( { message : " Valid email " } ) ;
import { env } from " $env/dynamic/private " ;
import arcjet , { protectSignup } from " @arcjet/sveltekit " ;
import { error , json } from " @sveltejs/kit " ;
// Limiting by IP is the default if not specified
//characteristics: ["ip.src"],
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// uses a sliding window rate limit
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes, but you may wish to increase this.
export async function POST ( event ) {
const { email } = await event . request . json () ;
const decision = await aj . protect ( event , {
// The submitted email is passed to the protect function
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//return error(503, { message: "Service unavailable" });
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
return error ( 400 , { message : " Invalid email " } ) ;
// This returns an error which is then displayed on the form, but you
// could take other actions such as redirecting to an error page
return error ( 403 , { message : " Forbidden " } ) ;
// User creation code goes here...
return json ( { message : " Valid email " } ) ;
import arcjet , { protectSignup } from " @arcjet/node " ;
import express from " express " ;
app . use ( express . urlencoded ( { extended : false } )) ;
// Get your site key from https://app.arcjet.com and set it as an environment
// variable rather than hard coding.
key : process . env . ARCJET_KEY ! ,
mode : " LIVE " , // will block requests. Use "DRY_RUN" to log only
// Block emails that are disposable, invalid, or have no MX records
block : [ " DISPOSABLE " , " INVALID " , " NO_MX_RECORDS " ] ,
// configured with a list of bots to allow from
// https://arcjet.com/bot-list
allow : [] , // "allow none" will block all detected bots
// It would be unusual for a form to be submitted more than 5 times in 10
// minutes from the same IP address
// uses a sliding window rate limit
interval : " 10m " , // counts requests over a 10 minute sliding window
max : 5 , // allows 5 submissions within the window
app . post ( " / " , async ( req , res ) => {
console . log ( " Email received: " , req . body . email ) ;
const decision = await aj . protect ( req , {
console . log ( " Arcjet decision " , decision ) ;
if ( decision . isErrored ()) {
// Fail open by logging the error and continuing
console . warn ( " Arcjet error " , decision . reason . message ) ;
// You could also fail closed here for very sensitive routes
//res.writeHead(503, { "Content-Type": "application/json" });
//res.end(JSON.stringify({ error: "Service unavailable" }));
if ( decision . isDenied ()) {
if ( decision . reason . isEmail ()) {
// If the email is invalid then return an error message
res . writeHead ( 400 , { " Content-Type " : " application/json " } ) ;
JSON . stringify ( { error : " Invalid email " , reason : decision . reason } ) ,
// We get here if the client is a bot or the rate limit has been exceeded
res . writeHead ( 403 , { " Content-Type " : " application/json " } ) ;
res . end ( JSON . stringify ( { error : " Forbidden " } )) ;