Rules and Segmentation
Prefab provides powerful rules that can you can compose to target exactly the users you're interested in.
Segments are reusable sets of rules that you can use across multiple feature flags.
tip
Rules are evaluated in order. You can drag and drop rules to rearrange them. The first matching rule determines which variant is served.
When a rule matches, you can either:
- Return a specific variant (e.g.
true,false, oryellow) - Return a variant based on a percentage (e.g.
true10% of the time andfalse90% of the time)
Note that the variant determined by percentage rollouts is "sticky" to the provided lookup key and won't change unless the key changes or the percentage values change.
Available Rules
String Rules
| Name | Function | Example usage | Notes |
|---|---|---|---|
Property Is One Of | Use Property Is One Of to target users with specific attributes. | If you set Criteria Property to subscription and Criteria Values to pro,advanced then it will match users with a pro or advanced subscription. | |
Property Is Not One Of | Use Property Is Not One Of to target users who do not match a specific attribute. | If you set Criteria Property to subscription and Criteria Values to pro,advanced then it will match users who have neither a pro nor an advanced subscription. | |
Property Ends With One Of | Use Property Ends With One Of to target users with an attribute that ends with a value. | If you set Criteria Property to email and Criteria Values to @example.com then it will match users who have an email ending with @example.com | |
Property Does Not End With One Of | Use Property Does Not End With One Of to target users with an attribute that does not end with a value. | If you set Criteria Property to email and Criteria Values to @gmail.com,@yahoo.com then it will match users who have an email that does not end with @gmail.com or @yahoo.com. | |
Property Starts With One Of | Use Property Starts With One Of to target users with an attribute that starts with a value. | See note below on SDK version requirements for new rule operators | |
Property Does Not Start With One Of | Use Property Does Not Starts With One Of to target users with an attribute that does not start with a value. | See note below on SDK version requirements for new rule operators | |
Property Contains One Of | Use Property Contains One Of to target users with an attribute that contains a value. | See note below on SDK version requirements for new rule operators | |
Property Does Not Contain One Of | Use Property Does Not Contain One Of to target users with an attribute that does not contain a value. | See note below on SDK version requirements for new rule operators | |
Property Matches | Use Property Matches to target users with an attribute that matches a regular expression (Regex) | See note below on SDK version requirements for new rule operators | |
Property Does Not Match | Use Property Does Not Match to target users with an attribute that does not match a regular expression (Regex) | See note below on SDK version requirements for new rule operators |
Numeric Rules
| Name | Function | Example usage | Notes |
|---|---|---|---|
Property Is Greater Than | Use Property Is Greater Than to target with a numeric attribute greater than a threshold | If you set Criteria Property to company.employees and Criteria Value to 100, then the rule will match users belonging to a company with more than 100 employees | See note below on SDK version requirements for new rule operators |
Property Is Greater Than Or Equal To | Use Property Is Greater Than Or Equal To to target with a numeric attribute greater than or equal threshold | If you set Criteria Property to company.employees and Criteria Value to 100, then the rule will match users belonging to a company with 100 or more employees | See note below on SDK version requirements for new rule operators |
Property Is Less Than | Use Property Is Less Than to target with a numeric attribute less than a threshold | If you set Criteria Property to company.employees and Criteria Value to 100, then the rule will match users belonging to a company with less than 100 employees | See note below on SDK version requirements for new rule operators |
Property Is Less Than Or Equal To | Use Property Is Less Than Or Equal To to target with a numeric attribute less than than or equal to a threshold | If you set Criteria Property to company.employees and Criteria Value to 100, then the rule will match users belonging to a company with 100 or fewer employees | See note below on SDK version requirements for new rule operators |
Date Rules
Note: Date context values can be specified as milliseconds since epoch or RFC3339 formatted strings
| Name | Function | Example usage | Notes |
|---|---|---|---|
Property Is Before | Use Property Is Before to target with a date attribute before than a threshold | If you set Criteria Property to user.createdAt and Criteria Value to '2025-01-01T00:00:00Z', then the rule will match users created before Jan 1, 2025. | See note below on SDK version requirements for new rule operators |
Property Is After | Use Property Is After to target with a date attribute after a threshold | If you set Criteria Property to user.createdAt and Criteria Value to '2025-01-01T00:00:00Z', then the rule will match users created after Jan 1, 2025. | See note below on SDK version requirements for new rule operators |
Semantic Version Rules
| Name | Function | Example usage | Notes |
|---|---|---|---|
Property Is Semver Less Than | Use Property Is Semver Less Than to target an attribute referring to a software version | If you set Criteria Property to sdk.version and Criteria Value to '2.0.0', then the rule will match versions less than 2.0.0 | See note below on SDK version requirements for new rule operators |
Property Is Semver Equal To | Use Property Is Semver Equal To to target an attribute referring to a software version | If you set Criteria Property to sdk.version and Criteria Value to '2.0.0', then the rule will match versions equal to than 2.0.0 | See note below on SDK version requirements for new rule operators |
Property Is Semver Greater To | Use Property Is Semver Greater Than to target an attribute referring to a software version | If you set Criteria Property to sdk.version and Criteria Value to '2.0.0', then the rule will match versions greater than 2.0.0 | See note below on SDK version requirements for new rule operators |
SDK Compatibility
The prefab-js and prefab-react SDKs evaluate rules remotely so any version will support the operaters with SDK Version requirements.
For in-process evaluation of the newer rules marked above these are the minimum versions
| Language | Version |
|---|---|
| Go | 0.2.1 |
| Java | 0.3.25 |
| Node | 0.4.8 |
| Python | 0.12.0 |
| Ruby | 1.8.9 |