Duplicate detection stops the same Cost document from being processed more than once. Depending on the mode you choose, Dext either deletes a suspected duplicate straight away or flags it so you can decide.
Important: Duplicate detection applies to Costs only, not Sales. The check runs while Dext processes the document, after data extraction finishes.
Duplicate detection and file rejection are two different checks
Dext runs two separate checks that both stop a document from going through, and they behave differently. Knowing which one you've hit tells you whether the document can be recovered.
File rejection happens when you submit the exact same file twice. Dext blocks it at upload, before it reaches your account, so no item is created and nothing appears in Submission history. You'll get the message "This item already exists in your account." This check always runs, regardless of your duplicate detection mode.
Duplicate detection happens when you submit a different file for the same purchase, such as a photo of a receipt you already emailed in. Dext creates the item, extracts the data, then compares it with your existing Cost items. The item can always be recovered.
Note: If you meant to upload the same document twice and Dext rejected it, changing your duplicate detection mode won't help. For the full list of rejection messages, go to Why was my document rejected?
Duplicate detection modes
Duplicate detection has three modes, and the mode decides what Dext does when it finds a match. You can set the mode as an account-wide default, for one supplier, or for several suppliers at once.
A supplier rule has a fourth option, Follow system settings. That's the default on every supplier, and it means the supplier uses whatever the account-wide mode is. Choose it again to undo a supplier rule you no longer want.
Automatic mode
In Automatic mode, Dext deletes a suspected duplicate as soon as it detects one. Deleted duplicates never reach the Costs inbox, so the upload can look like it simply vanished.
You'll find them in Submission history with the status Confirmed duplicate, and you can restore any of them. For the steps, go to Why was my Cost item marked as a duplicate?
Review mode
In Review mode, Dext keeps the suspected duplicate and gives it the status To review in the Costs inbox, with an amber dot beside the row. Nothing is deleted until someone decides.
You can then open the two items side by side, confirm whether they're the same purchase, and choose what happens to each.
Review mode is the better choice if you regularly submit separate purchases that look alike. Several identical fares, or repeat charges from one supplier on the same day, are typical cases.
Duplicate detection off
With duplicate detection off, Dext runs no comparison at all, and every Cost item is processed normally. We don't recommend this, because duplicates then reach your accounting software unflagged.
If you're turning it off because you keep getting false matches, switch that supplier to Review mode instead. You keep the safety net and still get every item into the inbox.
Set a default mode for all suppliers
To set the mode Dext uses across the whole account, change the account-level setting in Business settings.
Go to Business settings > Extraction.
Scroll to Duplicate items or select it in the sub-navigation.
Choose a mode in Duplicate cost items.
This becomes the default for every supplier that doesn't have its own rule.
Set a mode for a specific supplier
To change how Dext treats one supplier, set a rule on that supplier record. A supplier rule overrides the account-wide default, so this is how you handle a supplier that produces a lot of look-alike documents.
Go to Costs > Suppliers.
Select the supplier.
In the Duplicate costs items drop-down menu, select the mode you want.
Note: If your account setting and a supplier rule disagree, the supplier rule wins. This is the most common reason duplicate detection may behave differently from the mode shown in Business settings.
Apply a mode to several suppliers at once
To change the mode for a group of suppliers in one go, use bulk edit on the Suppliers page.
Go to Costs > Suppliers.
Select the suppliers using the checkboxes.
Select Bulk edit.
Choose a rule under Duplicate costs items.
Select Apply.
Note: Changing settings in bulk doesn't change items already in your inbox. The new mode applies to items arriving afterwards, so anything already flagged or deleted still has to be handled separately.
Who can change settings and review duplicates
Duplicate detection is restricted to admin-level roles, for both the settings and the review itself.
Only Admin users can change duplicate detection settings. Accountants and bookkeepers working in a client account act as Admins by default.
Standard users can't review suspected duplicates, even when Review mode is on. They won't see the Review item option at all, so a flagged item stays flagged until an admin handles it.
For a breakdown of what each role can do, go to Roles and permissions in Dext
What duplicate detection doesn't cover
Duplicate detection is a check on documents entering Dext, not a payment control, so there are gaps it won't close.
It compares a new item only against Cost items that have finished processing in the same Dext account. An item still being extracted isn't compared.
It never runs on Sales items.
It skips items that are already in an approval request or an expense claim.
It doesn't look at anything already published to your accounting software beyond the matching Cost item in Dext.
To catch duplicates that reached Xero or QuickBooks Online, go to Using the Duplicate transactions check