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:
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:
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.
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.
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 IP analysis in the
SDK reference for more information.
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:
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.
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.
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 ERRORconclusion.
Arcjet runs the same in any environment, including locally and in CI. You can
use the mode set to DRY_RUN to log the results of rule execution without
blocking any requests.
We have an example test framework you can use to automatically test your rules.
Arcjet can also be triggered based using a sample of your traffic.