Rules are used to enable a flag for a subset of users. Rules are evaluated from top to bottom. If a rule matches, the flag will return the configured value and stop evaluating the remaining rules.
See the example below.
Each rule has an attribute (1), a comparison operator (2), one or multiple targets (3) and an output value (4).
The city name for the location of the requester's public IP address. Non-ASCII characters are encoded according to RFC3986.
Countries are identified by their ISO 3166-1 alpha-2 code.
We provide a list of many available countries as suggestions in the input component in the console.
The public IP address of the client that made the request.
A string of up to three characters containing the region-portion of the ISO 3166-2 code for the first level region associated with the requester's public IP address.
Unfortunately, there is no official extensive list of available regions from Vercel.
You can use custom attributes to enable a flag for a subset of users. For
example, you can enable a flag for users with a specific userId or email.
Please refer to the API documentation for more information on how to set custom attributes.
These are the available rule types. Each of them includes a small code snippet that shows the exact implementation for reference
value is the value of the attribute. target is what we compare the attribute
value to.
The rule will apply if the attribute is in the target array.
return target.includes(attribute);The rule will apply if the attribute is not in the target array.
return !target.includes(attribute);The rule will apply if the attribute contains the specified target.
return attribute.includes(target);The rule will apply if the attribute value does not contain the specified target.
return !attribute.includes(target);The rule will apply if the attribute value equals the specified targe.
return attribute === target;The rule will apply if the attribute value does not equal the specified target.
return attribute !== target;The rule will apply if the attribute value is empty.
return attribute === "";The rule will apply if the attribute value is not empty.
return attribute !== "";The rule will apply if the attribute value is greater than the specified value.
return attribute > target;The rule will apply if the attribute value is greater than or equals the specified value.
return attribute >= target;The rule will apply if the attribute value is less than the specified value.
return attribute < target;The rule will apply if the attribute value is less than or equals the specified value.
return attribute <= target;The following flag will be evaluated for 80% of all users and enabled for those
in Germany or the United Kingdom and for users with the attribute userId set
to chronark.
Let's assume our user is lucky enough to be chosen for the 80% and is located in Germany: The order of operations is as follows:
- Evaluate percentage: ✅
- Evaluate country: ✅ Since the user is located in Germany, and that is one of
the countries specified in the rule, the value
truewill be returned.
Our user is located in Norway and their userId is chronark, the order of
operations is as follows:
- Evaluate country: ❌
- Evaluate userId: ✅
All rules will be avaluated until one of them matches. In this case, the flag
will return true.
Our user is not lucky enough to be chosen for the 80%:
In this case the rules will not be avalated and the flag returns false
Lastly, let's look at what happens if none of the rules match:
If your user is in the United States, and their username is not chronark:
- Evaluate country: ❌
- Evaluate userId: ❌
The flag will return false.