Consecutive weekends worked

There are different techniques for managing employees' working hours.

For different scenarios see Work limits.

This guide shows you how to manage employees' hours with consecutive weekends worked. This puts a limit on how many consecutive weekends employees can work in a period, for instance, if employees should only work one consecutive weekend throughout a period of one month.

Period rules for weekends can be defined for a month or the entire schedule.

Prerequisites

Learn how to configure an API Key to run the examples in this guide:

Log in to Timefold Platform: app.timefold.ai
From the Dashboard, click your tenant, and from the drop-down menu select Tenant Settings, then choose API Keys.
Create a new API key or use an existing one. Ensure the list of models for the API key contains the Employee Shift Scheduling model.

In the examples, replace <API_KEY> with the API Key you just copied.

1. Define consecutive weekends worked

Period rules are defined in contracts:

{
  "contracts": [
    {
      "id": "fullTimeContract",
      "periodRules": [
        {
          "id": "Max1ConsecutiveWeekendPerMonth",
          "period": "MONTH",
          "consecutiveWeekendsLimit":
          {
            "consecutiveWeekendsWorkedMax": 1
          },
          "satisfiability": "REQUIRED"
        }
      ]
    }
  ]
}

Period rules can define how many consecutive weekends employees work in a given period, for instance, a maximum of 1 consecutive weekend at a time per month.

PeriodRules must include an ID.

period sets the period the rule applies to, for instance, DAY, WEEK, MONTH, SCHEDULE.

Further information about period:

DAY spans a single day and occurs every day in the schedule.

WEEK spans 7 days and occurs every week (including partial weeks) in the schedule. The default start of the week is Monday, but this can be overridden to any day in the week:

{
  "scheduleParameterization": {
    "weekStart": "THURSDAY"
  }
}

MONTH spans the entire month. MONTH has a variable number of days depending on the days in the month and occurs every month (including partial months) in the schedule.

SCHEDULE spans the entire schedule.

You can define custom periods to apply to this rule in the following way:

{
  "scheduleParameterization": {
    "periods": [
      {
        "id": "PAY_PERIOD",
        "dateSpans": [
          {
            "start": "2023-01-01",
            "end": "2023-01-15"
          }
        ]
      }
    ]
  }
}

The start and end dates are inclusive.

consecutiveWeekendsLimit rules can only be defined for periods MONTH or SCHEDULE.

Learn about counting days in period rules:

By default, period rules count shifts within the defined period if the shift starts within the defined period. For instance, if you define a rule that an employee can only work 1 shift a day, a night shift that started on the previous day but ends the following morning will not be counted and another shift might be assigned on the same day as the night shift ended.

To change this behavior change the field periodShiftOverlapKind from START_ONLY to START_AND_END.

{
  "periodRules": [
    {
      "id": "Max8HoursPerDayFullTime",
      "period": "DAY",
      "minutesWorkedMax": 480,
      "satisfiability": "REQUIRED",
      "periodShiftOverlapKind": "START_AND_END"
    }
}

The consecutiveWeekendsLimit object must include consecutiveWeekendsWorkedMax with the maximum number of consecutive weekend to be worked.

periodRules can include or exclude shifts based on shift tags.

{
  "contracts": [
    {
      "id": "fullTimeContract",
      "periodRules": [
        {
          "id": "Max1ConsecutiveWeekendPerMonth",
          "period": "MONTH",
          "includeShiftTags": ["Part-time"],
          "shiftTagMatches": "ALL",
          "consecutiveWeekendsLimit":
          {
            "consecutiveWeekendsWorkedMax": 1
          },
          "satisfiability": "REQUIRED"
        }
      ]
    }
  ]
}

Further information about including or excluding shifts with shift tags:

Shifts with specific tags can be included or excluded by the rule. Tags are defined in shifts:

{
  "shifts": [
    {
      "id": "2027-02-01",
      "start": "2027-02-01T09:00:00Z",
      "end": "2027-02-01T17:00:00Z",
      "tags": ["Part-time"]
    }
  ]
}

Use includeShiftTags to include shifts with specific tags or excludeShiftTags to exclude shifts with specific tags.

shiftTagMatches can be set to ALL or ANY. The default behavior for shiftTagMatches is ALL, and if omitted, the default ALL will be used.

The rule can define either includeShiftTags or excludeShiftTags, but not both.

{
  "includeShiftTags": ["Part-time", "Weekend"],
  "shiftTagMatches": "ALL"
}

With shiftTagMatches set to ALL, all tags defined by the rule’s includeShiftTags attribute must be present in the shift. With shiftTagMatches set to ANY, at least one tag defined by the rule’s includeShiftTags attribute must be present in the shift.

{
  "excludeShiftTags": ["Part-time", "Weekend"],
  "shiftTagMatches": "ALL"
}

With shiftTagMatches set to ALL, all tags defined by the rule’s excludeShiftTags attribute cannot be present in the shift. This is useful when you want to exclude things in combination with each other. For instance, excluding the shift tags Part-time and Weekend with shiftTagMatches set to All, will exclude shifts that include the tags Part-time and Weekend from the rule. Shifts tagged only Part-time or only Weekend will not be excluded.

With shiftTagMatches set to ANY, any of the tags defined by the rule’s excludeShiftTags attribute cannot be present in the shift. This is useful when you need to exclude tags regardless of their relationship to other tags. For instance, excluding the shift tags Part-time and Weekend with shiftTagMatches set to ANY, will exclude any shift that includes the tags Part-time or Weekend, whether they occur together or not.

Each employee must specify which contracts apply to them:

{
  "employees": [
    {
      "id": "Ann",
      "contracts": [
        "fullTimeContract"
      ]
    }
  ]
}

The satisfiability can be REQUIRED or PREFERRED. If omitted, REQUIRED is the default.

2. Required consecutive weekends worked

When the satisfiability of the rule is REQUIRED, the Consecutive weekends worked not in required range for employee hard constraint is invoked, which makes sure the number of consecutive weekend worked does not exceed the limit specified in consecutiveWeekendsWorkedMax.

Shifts will be left unassigned if assigning them would break the Consecutive weekends worked not in required range for employee constraint.

In the following example, there are 8 shifts, 1 employee, and a rule with a required satisfiability that specifies the employee can work at most 1 consecutive weekend.

Employees may work more than 1 weekend during the month but these weekends must not be consecutive.

Only the weekend shifts are shown in the example.

4 shifts on 2 weekends are assigned and 4 shifts on 2 weekends are left unassigned to avoid breaking the Consecutive weekends worked not in required range for employee hard constraint.

Input
Output

Try this example in Timefold Platform by saving this JSON into a file called sample.json and make the following API call:

curl -X POST -H "Content-type: application/json" -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules [email protected]

{
  "config": {
    "run": {
      "name": "Required consecutive weekends worked example"
    }
  },
  "modelInput": {
    "contracts": [
      {
        "id": "fullTimeContract",
        "periodRules": [
          {
            "id": "Max1ConsecutiveWeekendPerMonth",
            "period": "MONTH",
            "consecutiveWeekendsLimit":
            {
              "consecutiveWeekendsWorkedMax": 1
            },
            "satisfiability": "REQUIRED"
          }
        ]
      }
    ],
    "employees": [
      {
        "id": "Ann",
        "contracts": [
          "fullTimeContract"
        ]
      }
    ],
    "shifts": [
      {
        "id": "Sat 6",
        "start": "2027-02-06T09:00:00Z",
        "end": "2027-02-06T17:00:00Z"
      },
      {
        "id": "Sun 7",
        "start": "2027-02-07T09:00:00Z",
        "end": "2027-02-07T17:00:00Z"
      },
      {
        "id": "Sat 13",
        "start": "2027-02-13T09:00:00Z",
        "end": "2027-02-13T17:00:00Z"
      },
      {
        "id": "Sun 14",
        "start": "2027-02-14T09:00:00Z",
        "end": "2027-02-14T17:00:00Z"
      },
      {
        "id": "Sat 20",
        "start": "2027-02-20T09:00:00Z",
        "end": "2027-02-20T17:00:00Z"
      },
      {
        "id": "Sun 21",
        "start": "2027-02-21T09:00:00Z",
        "end": "2027-02-21T17:00:00Z"
      },
      {
        "id": "Sat 27",
        "start": "2027-02-27T09:00:00Z",
        "end": "2027-02-27T17:00:00Z"
      },
      {
        "id": "Sun 28",
        "start": "2027-02-28T09:00:00Z",
        "end": "2027-02-28T17:00:00Z"
      }
    ]
  }
}

To request the solution, locate the 'ID' from the response to the post operation and append it to the following API call:

curl -X GET -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules/<ID>

{
  "run": {
    "id": "ID",
    "name": "Required consecutive weekends worked example",
    "submitDateTime": "2025-06-16T01:47:56.888557297Z",
    "startDateTime": "2025-06-16T01:48:09.332092002Z",
    "activeDateTime": "2025-06-16T01:48:09.495985633Z",
    "completeDateTime": "2025-06-16T01:48:40.483210883Z",
    "shutdownDateTime": "2025-06-16T01:48:40.792176606Z",
    "solverStatus": "SOLVING_COMPLETED",
    "score": "0hard/-4medium/0soft",
    "tags": [
      "system.profile:default"
    ],
    "validationResult": {
      "summary": "OK"
    }
  },
  "modelOutput": {
    "shifts": [
      {
        "id": "Sat 6",
        "employee": "Ann"
      },
      {
        "id": "Sun 7",
        "employee": "Ann"
      },
      {
        "id": "Sat 13"
      },
      {
        "id": "Sun 14"
      },
      {
        "id": "Sat 20",
        "employee": "Ann"
      },
      {
        "id": "Sun 21",
        "employee": "Ann"
      },
      {
        "id": "Sat 27"
      },
      {
        "id": "Sun 28"
      }
    ]
  },
  "inputMetrics": {
    "employees": 1,
    "shifts": 8,
    "pinnedShifts": 0
  },
  "kpis": {
    "assignedShifts": 4,
    "unassignedShifts": 4,
    "disruptionPercentage": 0.0,
    "activatedEmployees": 1,
    "assignedMandatoryShifts": 4,
    "assignedOptionalShifts": 0,
    "travelDistance": 0
  }
}

modelOutput contains the schedule with 4 shifts assigned on 2 non-consecutive weekends. 4 shifts on 2 other weekends are left unassigned.

inputMetrics provides a breakdown of the inputs in the input dataset.

KPIs provides the KPIs for the output including:

{
  "assignedShifts": 4,
  "unassignedShifts": 4,
  "activatedEmployees": 1,
  "assignedMandatoryShifts": 4
}

3. Preferred consecutive weekends worked

When the satisfiability of the rule is PREFERRED, the Consecutive weekends worked not in preferred range for employee soft constraint is invoked.

{
  "contracts": [
    {
      "id": "fullTimeContract",
      "periodRules": [
        {
          "id": "Max1ConsecutiveWeekendPerMonth",
          "period": "MONTH",
          "consecutiveWeekendsLimit":
          {
            "consecutiveWeekendsWorkedMax": 1
          },
          "satisfiability": "PREFERRED"
        }
      ]
    }
  ]
}

Shifts will be assigned to employees even if the shifts take the employee’s consecutive weekends worked over the limit specified by consecutiveWeekendsWorkedMax, however, this constraint adds a soft penalty to the run score for any matches to the constraint, incentivizing Timefold to find an alternative solution.

In the following example, there are 8 shifts, 1 employee, and a rule with a preferred satisfiability that specifies the employee should work at most 1 consecutive weekend per month.

All 8 shifts are assigned, and a soft penalty is applied to the score run.

Input
Output

Try this example in Timefold Platform by saving this JSON into a file called sample.json and make the following API call:

curl -X POST -H "Content-type: application/json" -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules [email protected]

{
  "config": {
    "run": {
      "name": "Preferred consecutive weekends worked example"
    }
  },
  "modelInput": {
    "contracts": [
      {
        "id": "fullTimeContract",
        "periodRules": [
          {
            "id": "Max1ConsecutiveWeekendPerMonth",
            "period": "MONTH",
            "consecutiveWeekendsLimit":
            {
              "consecutiveWeekendsWorkedMax": 1
            },
            "satisfiability": "PREFERRED"
          }
        ]
      }
    ],
    "employees": [
      {
        "id": "Ann",
        "contracts": [
          "fullTimeContract"
        ]
      }
    ],
    "shifts": [
      {
        "id": "Sat 6",
        "start": "2027-02-06T09:00:00Z",
        "end": "2027-02-06T17:00:00Z"
      },
      {
        "id": "Sun 7",
        "start": "2027-02-07T09:00:00Z",
        "end": "2027-02-07T17:00:00Z"
      },
      {
        "id": "Sat 13",
        "start": "2027-02-13T09:00:00Z",
        "end": "2027-02-13T17:00:00Z"
      },
      {
        "id": "Sun 14",
        "start": "2027-02-14T09:00:00Z",
        "end": "2027-02-14T17:00:00Z"
      },
      {
        "id": "Sat 20",
        "start": "2027-02-20T09:00:00Z",
        "end": "2027-02-20T17:00:00Z"
      },
      {
        "id": "Sun 21",
        "start": "2027-02-21T09:00:00Z",
        "end": "2027-02-21T17:00:00Z"
      },
      {
        "id": "Sat 27",
        "start": "2027-02-27T09:00:00Z",
        "end": "2027-02-27T17:00:00Z"
      },
      {
        "id": "Sun 28",
        "start": "2027-02-28T09:00:00Z",
        "end": "2027-02-28T17:00:00Z"
      }
    ]
  }
}

To request the solution, locate the 'ID' from the response to the post operation and append it to the following API call:

curl -X GET -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules/<ID>

{
  "run": {
    "id": "ID",
    "name": "Preferred consecutive weekends worked example",
    "submitDateTime": "2025-06-16T02:00:10.792070405Z",
    "startDateTime": "2025-06-16T02:00:23.377085397Z",
    "activeDateTime": "2025-06-16T02:00:23.585340881Z",
    "completeDateTime": "2025-06-16T02:00:54.477220847Z",
    "shutdownDateTime": "2025-06-16T02:00:54.735303287Z",
    "solverStatus": "SOLVING_COMPLETED",
    "score": "0hard/0medium/-2880soft",
    "tags": [
      "system.profile:default"
    ],
    "validationResult": {
      "summary": "OK"
    }
  },
  "modelOutput": {
    "shifts": [
      {
        "id": "Sat 6",
        "employee": "Ann"
      },
      {
        "id": "Sun 7",
        "employee": "Ann"
      },
      {
        "id": "Sat 13",
        "employee": "Ann"
      },
      {
        "id": "Sun 14",
        "employee": "Ann"
      },
      {
        "id": "Sat 20",
        "employee": "Ann"
      },
      {
        "id": "Sun 21",
        "employee": "Ann"
      },
      {
        "id": "Sat 27",
        "employee": "Ann"
      },
      {
        "id": "Sun 28",
        "employee": "Ann"
      }
    ]
  },
  "inputMetrics": {
    "employees": 1,
    "shifts": 8,
    "pinnedShifts": 0
  },
  "kpis": {
    "assignedShifts": 8,
    "unassignedShifts": 0,
    "disruptionPercentage": 0.0,
    "activatedEmployees": 1,
    "assignedMandatoryShifts": 8,
    "assignedOptionalShifts": 0,
    "travelDistance": 0
  }
}

modelOutput contains the schedule with all 8 shifts on 4 consecutive weekends assigned to Ann.

inputMetrics provides a breakdown of the inputs in the input dataset.

KPIs provides the KPIs for the output including:

{
  "assignedShifts": 8,
  "activatedEmployees": 1,
  "assignedMandatoryShifts": 8
}

See the full API spec or try the online API.
Learn more about employee shift scheduling from our YouTube playlist.
See other options for managing employees' work hours: Work limits.

Consecutive weekends worked

Prerequisites

1. Define consecutive weekends worked

2. Required consecutive weekends worked

3. Preferred consecutive weekends worked

Next