Mass Mail is a special approach to Picking that can be beneficial when there are a large number of Orders requiring the same set of items. Mass Mail Picking utilizes existing features in WOS in a combination that makes fulfilling these large volume of like Orders more efficient. This approach to Picking will generally require an integration with a shipping system to generate and automatically print the labels related to the Orders. 

Mass Mail Cart Type

A special Cart Type needs to be created. The Cart Type must be named "MassMail". This Cart Type can be created to hold 200-300 orders by designating a row and column configuration that matches the desired quantity of Orders (20x10, for example).

Batching to the Mass Mail Cart Type

When creating Batches, Orders must be identified to meet the matching profile. A few approaches can be used to identify the Orders. Full Order Zone is the suggested approach.

  • Full Order Zone
    • Designate a set of Locations into a special type of Priority Zone. Flag the Zone as a Full Order Zone.
    • As Items are put into this Full Order Zone, Orders that can be fully picked from this Zone will identified by the Zone Name in the Full Order Zone column.
    • An option when Batching will reallocate all the Orders to Pick from this Zone.
    • This will not limit the filter to Orders that contain all Items, only that all of the Items on the Order are in the Full Order Zone. (for example, if the Full Order Zone has 5 Items and the Order only has 2 of those Items, the Order will be presented in the list).
  • Bundles
    • Create a Bundle with all of the Items in the desired profile. Orders that match this Bundle will show the Bundle Name in the Unassigned grid.
    • The Bundle Name can be used to filter for Orders that match the set Bundle.
    • This will ensure that only Orders that contain all of the Items in the Bundle are identified.
    • This will not limit the Order to only the single Bundle. If the Order has additional Items in it, the Bundle will still show in the list. Identifying the count of lines will be required to limit the list to Orders that only have Items in the Bundle.
  • Cells
    • Configure and stock a Cell with the inventory desired for the Mass Mail profile.
    • If all the Items in the Order match to a cCll, the Cell Group will be shown on the Order.
    • This will not limit the filter to Orders that contain all Items, only that all of the Items on the Order are in the Cell Group.
    • This option does not allow the Order to be reallocated to this Cell to be used in Batch Picking. 

Picking a Mass Mail Cart

With a few specific settings, a Mass Mail Cart can be picked in bulk without having to consolidate each item into the compartments assigned to the Orders. In the Group Settings, enable the option "Enable Put Complete Scan". This setting allows the Picker to scan the Cart Number instead of individual compartments. When a Cart is scanned, all Orders needing the picked Item are automatically completed.

The Batch must be Picked using a Device that is assigned to a Print Station. The Print Station assigned to the Device should be the one at the Pack Station where the Batch will be completed. This is important in the next step when shipping labels are printed for the Batch.

WARNING: Using this setting will bypass the verification built into the WOS Picking app. Items are not scanned into each compartment and are instead picked in bulk. The efficiency of the Pick is sacrificing the ability to verify that the correct quantity of items have been picked. There will be no way to accurately verify that the Picker has the correct quantity of Items until all Orders are packed.

Note: WOS requires that inventory is picked to a Cart. However, it is possible to make this a symbolic pick. If inventory can be staged at the Pack Stations, the physical inventory can be Picked for the first time during the Packing stage. In this approach, the Pick that WOS requires becomes more symbolic, adjusting inventory down for the Items about to be Packed and triggering the shipping labels to be printed, but not actually requiring physical inventory be Picked and moved into position.

Integration with Shipping Labels

When the Batch has been completely Picked, an integration against the Batch Complete message will identify that the completed Batch is on a Mass Mail Cart. Requests to the shipping service provider will begin generating labels for all of the Orders on the Batch. The labels will immediately be sent to the printer assigned to the Device that Picked the Batch. The labels will be printed in a random order as they are generated in the shipping service.

An optional setting within a Zebra Printer can pause after each label until the label is cleared. This will provide some control to the packing process so that each Order can be packed individually as each label prints out. If this setting is not used, all of the 200-300 labels related to the batch will be printed immediately.

It is recommended to have the Order Number barcoded on the shipping label so this can be scanned into Packing to pull up the Order.

This is an additional and separate data flow that must be enabled on your integration. If the WarehouseOS Team is managing your integration with your shipping provider, reach out to to have this flow added to your project.

Note: Because labels are generated and printed in a random order, it's not possible to line up the printing of the shipping label and an additional document. Both sets of documents will print at random and won't line up in a clean way if printed automatically.

Packing a Mass Mail Cart

If the number of lines on the Order are variable, meaning some Orders have 2 lines and some have 5 lines, it is recommended to use the Packing App to complete the Order. This allows the Order to be "Picked" out of the bulk inventory that was placed on the Cart during the Batch Pick process.

If the individual Order scans are being bypassed, Verify can be used to complete all Orders on the Cart in one step. 

WARNING: Using the Verify All option will bypass the verification built into WOS at the Packing step. Bypassing both Picking and Packing means there was no digital verification that a specific Order was completed. Any discrepancies in quantities left on the Cart, Orders not shipped, or any other issues won't have any real system details to assist in identifying where the issues are. The efficiency in applying labels in bulk is sacrificing the ability to verify details at the Order level.


  1. Scan the Cart number to pull up the Order Details into the Packing app.
  2. Scan the barcode off the printed shipping label to pull up the related Order.
  3. A list of the needed Items are displayed in the Packing app.
  4. Find and Pick the Items off the Cart; scanning each Item to verify that the correct Item was found.
  5. When all Items are scanned, tear the label from the printer and apply to the package.
  6. The next label will automatically print allowing it to be scanned to identify the next Order.


  1. Scan the Cart Number to pull up the Order Details into the Verify app.
  2. Use the Verify All option to mark all Orders as verified and clear the Cart.
  3. Assemble the Picked Items into Orders and apply a label from the stream of printed labels until all labels have been used.

Mass Mail Label Report

A report can help identify possible issues related to the labels that were printed during the Mass Mail process. The report allows for a date range to be selected. The report highlights problem Orders that were Picked within the selected date range.

  • A label failed to generate and never made it to WOS.
  • A label was generated but failed to print. This status simply means that the WOS Print Agent was unable to verify that the print job was accepted by the printer. It is not a direct status indicating whether the document was actually printed.
  • An Error label was generated indicating that a new shipping label must be reprinted and applied.

Options in the report will allow all Orders Picked through the Mass Mail process to be shown and reviewed.