Skip to main content
Constraints are used to specify rules that the solver should follow when generating rosters. They allow you to control shift assignments, employee availability, work patterns, and other aspects of roster generation to ensure the resulting schedule meets your business requirements.

​
Constraint importance

Constraints can be configured with different levels of importance:

​
Strict constraints

When a constraint is set to STRICT importance, the solver will never violate it. These constraints act as hard requirements that must be satisfied for the roster to be valid. If the solver cannot satisfy all strict constraints, it will fail to generate a roster.

​
Importance levels

Alternatively, constraints can be assigned a regular importance level that indicates how strongly the solver should consider the rule: VERY_LOW, LOW, MEDIUM, HIGH, or VERY_HIGH. The solver will attempt to satisfy constraints with higher importance levels more strongly, but may violate them if necessary to satisfy strict constraints or other higher-priority requirements.

​
Filters

Every constraint can receive filters which allow you to make the constraint apply only to specific employees or shifts. This provides fine-grained control over which parts of your roster are affected by each constraint. Filters can target entities in two ways:
  • By ID: Specify exact IDs of employees or shifts that the constraint should apply to
  • By labels: Specify labels that employees or shifts must have for the constraint to apply
For example, you might want a constraint that only applies to employees with the label "senior" working shifts with the label "night". This allows you to create complex, targeted rules for different groups of employees and shifts.
Below is an example of a HIGH importance constraint that applies to employees with the id employee-1 and employee-2 working shifts with the label night.
{
  "id": "constraint-123",
  "labels": ["night-shifts", "senior-staff"],
  "importance": "HIGH",
  "filters": {
    "employees": {
      "ids": ["employee-1", "employee-2"]
    },
    "shifts": {
      "labels": ["night"]
    }
  }
}
Note that each constraint will have additional fields specific to the constraint type.

​
Available constraints

Employee Availability

Specify when employees are (preferably) available for work.

Employee Utilization

Control the minimum and maximum utilization of employees over specific periods.

Cooldown

Define minimum rest periods between shifts for employees.

Consecutive

Control the minimum and maximum number of consecutive shifts.

Pattern

Define work patterns that employees should follow.

Periodic Rest

Ensure employees get rest periods at regular intervals.

Period Distribution

Control how work is distributed across different periods.