Rule Operators

Rules control the flow of a questionnaire. After a user answers a question, the rules engine evaluates conditions to determine which question to show next.

Rule Components

There are four rule component types available in the Strapi rules dynamic zone:

1. rule-comparison

A single condition with if/then/else branching.

Field	Type	Description
`if`	condition	The comparison to evaluate
`then`	string	Question ID to navigate to if the condition is true
`else`	string	Question ID to navigate to if the condition is false

Example: If the user’s country is Germany, go to the German-specific question; otherwise, go to the generic question.

{
  "if": {
    "op": "equals",
    "variable": { "type": "static", "value": "DE" }
  },
  "then": "germanSpecificQuestion",
  "else": "genericQuestion"
}

2. rule-group-comparison

Grouped conditions combined with AND/OR logic.

Field	Type	Description
`condition`	enum	`AND` or `OR`
`comparisons`	array	Array of individual comparisons
`then`	string	Question ID if the group evaluates to true
`else`	string	Question ID if the group evaluates to false

Example: If the user is over 18 AND lives in Germany, go to the standard flow.

{
  "condition": "AND",
  "comparisons": [
    { "op": "greaterThan", "key": "age", "variable": { "type": "static", "value": 18 } },
    { "op": "equals", "key": "country", "variable": { "type": "static", "value": "DE" } }
  ],
  "then": "standardFlow",
  "else": "blockerScreen"
}

3. rule-date

Date-based comparison using dateDiff.

Field	Type	Description
`op`	string	Always `dateDiff`
`variable.type`	enum	Unit: `year`, `month`, or `day`
`variable.value`	number	The threshold value to compare against
`variable.dir`	enum	Direction: `gt` (greater than) or `lt` (less than)
`variable.key`	string	Question ID containing the date answer
`variable.comparisonKey`	string	Optional: another question ID to compare against (instead of today’s date)
`then`	string	Question ID if true
`else`	string	Question ID if false

Example: If the user’s date of birth is more than 65 years ago, route to a senior-specific flow.

{
  "op": "dateDiff",
  "variable": {
    "type": "year",
    "value": 65,
    "dir": "gt",
    "key": "dateOfBirth"
  },
  "then": "seniorFlow",
  "else": "standardFlow"
}

Example with comparisonKey: If the gap between two dates is less than 30 days.

{
  "op": "dateDiff",
  "variable": {
    "type": "day",
    "value": 30,
    "dir": "lt",
    "key": "travelStartDate",
    "comparisonKey": "travelEndDate"
  },
  "then": "shortTripFlow",
  "else": "longTripFlow"
}

4. rule-always

Unconditional routing — always navigates to the target question.

Field	Type	Description
`then`	string	Question ID to always navigate to

Example: After the intro screen, always go to the first question.

{
  "then": "dateOfBirth"
}

Comparison Operators

These operators are used inside rule-comparison and rule-group-comparison conditions.

Value Comparison

Operator	Description	Example
`equals`	Deep equality check (`===` semantics for primitives, deep compare for objects/arrays)	Answer is exactly `"DE"`
`notEquals`	Deep inequality check	Answer is not `"DE"`
`same`	Loose equality (`==` semantics)	Answer loosely matches `42`
`notSame`	Loose inequality (`!=` semantics)	Answer does not loosely match `42`
`greaterThan`	Answer is greater than the value	Answer > `18`
`lessThan`	Answer is less than the value	Answer < `65`

Collection Comparison

Operator	Description	Example
`isIn`	Answer is contained in the provided array	Answer is one of `["DE", "AT", "CH"]`
`isNotIn`	Answer is not in the provided array	Answer is not in `["US", "UK"]`
`contains`	Answer (string or array) contains the value	Answer contains `"health"`
`notContains`	Answer does not contain the value	Answer does not contain `"excluded"`

Existence Check

Operator	Description	Example
`isDefined`	Answer is not `null` and not `undefined`	User has answered the question
`isNotDefined`	Answer is `null` or `undefined`	User has not answered the question

Country-Specific

Operator	Description
`equalsOrContainsCountryCode`	Answer equals or contains the specified country code
`notEqualOrContainsCountryCode`	Answer neither equals nor contains the specified country code
`doCountryCodesMatch`	The country codes in the answer match the specified codes
`doCountryCodesNotMatch`	The country codes in the answer do not match
`doAllCountryCodesMatch`	All country codes in the answer match (for multi-country questions)
`doAllCountryCodesNotMatch`	Not all country codes match

Address-Specific

Operator	Description
`doesAddressMatch`	Address answer matches the comparison address
`doesAddressNotMatch`	Address answer does not match

Unconditional

Operator	Description
`always`	Always evaluates to true. Use for unconditional routing.

Variable Types

Each comparison operator uses a variable to define what the answer is compared against.

Static Variable

Compare the answer against a fixed, hardcoded value.

{
  "op": "equals",
  "variable": {
    "type": "static",
    "value": "DE"
  }
}

Field	Type	Description
`type`	string	`"static"`
`value`	any	The fixed value to compare against (string, number, boolean, array, or object)

Dynamic Variable

Compare the answer against another question’s answer.

{
  "op": "equals",
  "variable": {
    "type": "dynamic",
    "key": "partnerCountry"
  }
}

Field	Type	Description
`type`	string	`"dynamic"`
`key`	string	The question ID whose answer to use as the comparison value

Use case: “If the user’s country of residence matches their country of origin, skip the visa question.”

Custom Functions (Code Only)

For cases where CMS operators are insufficient, rules can include custom JavaScript functions defined in app code. These are not configurable from Strapi.

Signature:

(answer: any, answers: Record<string, any>, questionId: string) => boolean

Parameter	Description
`answer`	The current question’s answer
`answers`	All answers collected so far (keyed by question ID)
`questionId`	The current question’s ID

Custom functions are defined in the questionnaire’s TypeScript file and referenced by the rules engine at runtime.

Evaluation Order

Rules are evaluated in the order they appear in Strapi. The first matching rule determines the next question. If no rule matches, the questionnaire follows the default question order (as defined in the questionList).