About weekend and holiday delivery

Shipium provides several settings that control weekend delivery behavior. Some of these are parameters you pass in your API requests, while others are your organization's configurations managed by your Shipium team members. Understanding how these settings interact is essential for accurate carrier selection and delivery date predictions.

Along with weekend schedules, carrier-observed holidays will impact transit times. This document includes information about both weekend and holiday delivery.

Request-level parameters

These parameters are included in your API requests and can vary per shipment.

saturdayDelivery flag

The saturdayDelivery flag controls whether service methods are filtered based on their Saturday delivery capability.

saturdayDelivery: false (default). No filtering occurs based on Saturday delivery capability. Service methods are evaluated normally, and if a service method's estimated delivery date lands on a Saturday, Shipium will pass the appropriate Saturday delivery indicator to the carrier.
saturdayDelivery: true. This flag filters out all service methods that cannot deliver on Saturday, regardless of your desired delivery date. Only service methods with Saturday delivery capability remain in the selection pool.

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Use saturdayDelivery flag with caution
Setting saturdayDelivery: true is a very constraining filter that significantly limits your carrier options. It excludes service methods that might deliver earlier than Saturday (such as Friday) simply because they don't support Saturday delivery. This can result in unexpected carrier selection or higher costs. Only use this flag when Saturday delivery capability is an absolute requirement.
Example of unintended consequences. A customer sets saturdayDelivery: true with a Wednesday desired delivery date (DDD). A ground service that would deliver on Friday gets filtered out because it doesn't support Saturday delivery, even though Friday is before the DDD. The system then selects a more expensive service unnecessarily.

You can find more information about Saturday delivery in Special Processing Properties.

desiredDeliveryDate (DDD)

The desiredDeliveryDate is the date you would like the shipment delivered. Shipium selects the carrier service that best meets this date target.

When DDD falls on a Saturday. Shipium evaluates service methods to find the best option to meet your Saturday target. If a service method's estimated delivery date lands on Saturday and that service charges a Saturday delivery fee, the system will consider that option and pass the Saturday delivery indicator to the carrier. The DDD expresses your delivery target—it does not filter out service methods that don't support Saturday delivery.
When DDD falls on a Sunday. Similar behavior applies for Sunday delivery targets. Key distinction. The DDD is a target date that influences carrier selection optimization, not a hard filter on service capabilities. If your DDD is Saturday but a service method would deliver on Friday (before your target), that service method remains eligible for selection.

How saturdayDelivery and DDD work together

The following scenarios illustrate the interaction:

Scenario A: DDD on Saturday, saturdayDelivery: false

Service methods are NOT filtered based on Saturday capability.
Shipium evaluates all eligible services to meet the Saturday target.
If a service's EDD lands on Saturday and requires a fee, the system passes the Saturday indicator to the carrier.
Services that deliver before Saturday (e.g., Friday) remain eligible.

Scenario B: DDD on Saturday, saturdayDelivery: true

Service methods that cannot deliver on Saturday are filtered out entirely.
Only Saturday-capable services are considered.
This may exclude services that could deliver earlier (Friday) at lower cost.
Use only when Saturday delivery capability is mandatory.

Scenario C: DDD on Wednesday, saturdayDelivery: true

Service methods that cannot deliver on Saturday are still filtered out.
Even though your target is Wednesday, non-Saturday-capable services are excluded.
This is rarely the desired behavior—consider whether you actually need this flag.

You can find more information about desired delivery date in Desired, Exact, & Guaranteed Delivery Dates.

sundayDelivery Flag

Similar to saturdayDelivery, this flag filters service methods based on Sunday delivery capability. Currently, Sunday delivery support varies significantly by carrier and geographic region. The same caution applies: setting this to true is a constraining filter.

Account settings configuration

These settings are configured at your account level by your Shipium Implementation or Customer Success team member. They apply to all shipments for your account.

weekendsConsiderTransitDays

This setting determines whether weekends are counted as transit days when calculating the estimated delivery date (EDD).

When set to false (default). Weekends are not counted as transit days. For example, if a shipment has a time-in-transit (TNT) of 2 days and is shipped on a Friday, the EDD will be Tuesday (shipping on Friday, Monday is day 1, Tuesday is day 2).
When set to true. Weekends are counted as transit days. For example, if a shipment has a TNT of 2 days and is shipped on a Friday, the EDD will be Sunday (shipping on Friday, Saturday is day 1, Sunday is day 2).

If you need to change this setting to match your operational requirements, contact your Shipium Implementation or Customer Success representative.

Interaction scenarios

Here are common scenarios that illustrate how these settings work in practice.

Scenario 1: DDD on Saturday, saturdayDelivery false, weekendsConsiderTransitDays false

Behavior. The system evaluates all eligible service methods to meet the Saturday target. No filtering occurs based on Saturday capability. If a service's EDD lands on Saturday, the Saturday delivery indicator is passed to the carrier (and applicable fees may apply).

Example. You ship on Thursday with a DDD of Saturday. A 2-day ground service would deliver Saturday. A 1-day express service would deliver Friday. Both are considered. The system selects based on cost optimization and your carrier selection rules. If the ground service is selected and its EDD is Saturday, the Saturday indicator is passed to the carrier.

Scenario 2: DDD on Saturday, saturdayDelivery true, weekendsConsiderTransitDays false

Behavior. The system filters out all service methods that cannot deliver on Saturday, then evaluates remaining options.

Example. You ship on Thursday with a DDD of Saturday. A 1-day express service that delivers Friday but doesn't support Saturday delivery is filtered out entirely, even though it would meet your DDD early. Only services with Saturday delivery capability are considered, potentially resulting in higher costs.

Scenario 3: DDD on Tuesday, weekendsConsiderTransitDays false

Behavior. The system calculates EDDs without counting weekends as transit days.

Example. A shipment with a 3-day TNT shipped on Friday has an EDD of Wednesday. The calculation skips Saturday and Sunday: Monday (day 1), Tuesday (day 2), Wednesday (day 3).

Scenario 4: DDD on Tuesday, weekendsConsiderTransitDays true

Behavior. The system calculates EDDs counting weekends as transit days.

Example. A shipment with a 3-day TNT shipped on Friday has an EDD of Monday: Saturday (day 1), Sunday (day 2), Monday (day 3).

Importance of accurate shippedDateTime

The shippedDateTime you provide in your API requests directly influences the accuracy of Shipium's transit time predictions. Providing an accurate ship date is one of the most important factors in getting reliable carrier selection results.

How Shipium processes shippedDateTime

When you provide a shippedDateTime, Shipium calculates an effective ship date based on carrier cutoffs and schedules. This ensures transit time predictions account for when the carrier will actually pick up the package.

Carrier cutoffs. If you provide a shippedDateTime that falls after the carrier's pickup cutoff time, Shipium automatically advances the effective ship date to the next eligible pickup date.

Example. You pass Friday at 5:00 PM as your shippedDateTime, but the carrier's cutoff is 3:00 PM on Friday. Shipium calculates the effective ship date as Monday (the next eligible pickup date) and uses that date to calculate the estimated delivery date.

additionalDaysToProcess. If your fulfillment operations require additional processing time before a package is ready for carrier pickup, you can configure additionalDaysToProcess in your account settings. This value is added to the shippedDateTime when calculating the effective ship date.

This processing helps ensure accurate delivery predictions even when shipments are created late in the day or when additional handling time is needed.

Why accuracy still matters

Even with these automatic adjustments, providing an accurate shippedDateTime remains critical. Shipium uses historical shipment data to train its transit time prediction models. If the shippedDateTime you provide is consistently earlier than when packages are actually ready for carrier pickup (beyond what carrier cutoffs account for), the system observes longer apparent transit times and adjusts predictions accordingly.

Example. You consistently pass Friday as your shippedDateTime, but due to internal processing delays, packages aren't actually ready for the carrier until Monday—even though the carrier cutoff would have allowed Friday pickup. The carrier delivers on Tuesday. From the prediction model's perspective, this appears to be a 4-day transit (Friday to Tuesday), when in reality it was a 1-day transit (Monday to Tuesday). Over time, this causes transit time predictions to become more conservative than necessary.

Best practices

To get the most accurate time-in-transit (TNT) predictions:

Align shippedDateTime with when packages are actually ready. If your fulfillment processes mean packages won't be ready until Monday, pass Monday as the shippedDateTime rather than Friday.
Use additionalDaysToProcess if needed. If your operations consistently require additional processing time, work with your Shipium representative to configure this setting rather than manually adjusting every shippedDateTime.
Account for carrier cutoffs. Understand your carrier cutoff times and reflect them in the shippedDateTime you provide. If a package won't be ready by Friday's 3:00 PM cutoff, pass Monday as the ship date.

If you're unable to align these dates due to operational constraints, contact your Shipium representative to discuss options such as route-specific TNT overrides or account-level configuration adjustments.

Carrier holidays

In addition to weekend considerations, carrier holidays affect delivery timing. Major carriers observe holidays throughout the year when pickup and delivery services are not available.

How holidays affect transit time

When a carrier holiday falls within a shipment's transit window, Shipium automatically accounts for this in delivery date calculations. The system adds the appropriate number of days to skip the holiday, similar to how weekends are handled when weekendsConsiderTransitDays is set to false.

Example. If you ship on Wednesday with a 2-day TNT and Thursday is a carrier holiday, the EDD calculation skips Thursday and adjusts accordingly..

Peak season considerations

During peak shipping seasons (particularly November through early January), carriers may have extended transit times due to volume. Additionally, carrier-specific holiday schedules may vary. When planning shipments around major holidays, consider building in buffer time for potential delays.

If you have questions about how specific carrier holidays affect your shipments, contact your Customer Success representative for guidance.

Common issues and solutions

Issue: Overly restrictive carrier selection

Symptom. Fewer carrier options than expected, or expensive services selected when cheaper options should be available.

Likely cause. You're passing saturdayDelivery: true when you don't actually need to filter for Saturday capability.

Solution. Remove the saturdayDelivery: true flag unless Saturday delivery capability is an absolute requirement. If you simply want delivery by Saturday, use the DDD parameter instead; it will target Saturday delivery without filtering out other options.

Issue: Unexpected Saturday fees

Symptom. Shipments incur Saturday delivery fees when you didn't expect them.

Likely cause. Your DDD falls on a Saturday, and the selected service method's EDD lands on Saturday, triggering the Saturday delivery indicator to be passed to the carrier.

Solution. If you want to avoid Saturday fees, set your DDD to Friday (delivery before the weekend) or Monday (delivery after the weekend). This removes Saturday as a target date.

Issue: EDD later than expected

Symptom. A 2-day service shipped on Friday shows an EDD of Tuesday instead of Sunday.

Likely cause. Your account's weekendsConsiderTransitDays setting is false (the default). The system skips Saturday and Sunday when counting transit days.

Solution. If your carriers actually move packages over the weekend and you need weekend days counted as transit time, contact your Shipium representative to discuss adjusting this setting.

Issue: Transit times seem too conservative

Symptom. Short-distance shipments receive 2-day or 3-day TNT predictions when you expect 1-day delivery.

Likely cause. Historical patterns show packages shipping later than the shippedDateTime provided (beyond what carrier cutoffs explain), causing predictions to be adjusted upward.

Solution. Audit your shippedDateTime accuracy. Ensure the date you pass reflects when packages are actually ready for pickup, accounting for your internal processing time. Contact your Shipium representative if you need to discuss TNT override options or additionalDaysToProcess configuration.

Resources

Your Shipium team member is available to help along the way. However, you might find these resources helpful: