You can easily validate three-way matching in Peakflo by following the steps in this article:
How to match receipt notes to purchase orders in Peakflo:
How to match purchase orders to bills in Peakflo:
How to match receipt notes to purchase orders in Peakflo:
1. Go to the “Receipt note” section under “payables”.
At a glance, you can check the receipt note status and whether or not it is matched to a PO from the "PO Number" column.
2. Open the Receipt note that you want to match with a PO and click on "Match PO".
3. Then choose the PO(s) that matches the receipt note.
4. Once the PO is matched, Peakflo will validate the line items and flag any mismatches.
5. When clicking on “save”, if there’s a mismatch, it will appear as a warning, and your AP team can leave comments and tag the stakeholders to resolve the warnings. 
Both warning and error validations will allow users to save the PO/RN/Bill. But error validations will not allow users to proceed for submission for approval
6. Once the PO is matched to the receipt note, in the receipt note table view, you can see the matched PO in the "PO Number" column. 
How to match purchase orders to bills in Peakflo:
1. To match the PO to the bill, go to the “Bills and Reimbursements” tab under “Payables”.
From the “PO Number” column, you can see if the purchase order number has been matched with the PO already. If this column is empty, then there are no POs matched.
2. Hover over the bill that you want to match with a PO, then click on the pencil icon on the screen.
3. Once the bill is opened, click the “Match PO” button.
4. The list of POs will be shown and you can choose the PO that matches the bill and click on “Proceed”.
5. Peakflo will automatically match the PO line items to the bill line items and flag the mismatches.
6. If there’s a mismatch, it will appear as a warning, and your AP team can leave comments and tag the stakeholders to resolve the warnings.
Match is done base on two factors:
- Balance quantity- Quantity yet to be received
- Balance amount- Amount yet to be billed
7. Once the PO is matched to the receipt note, in the bills and reimbursement table view, you can see the matched PO in the "PO Number" column. 
Now the invoice, purchase order, and receipt note are all matched in Peakflo and the three-way matching is complete!