Assembly charges fees your platform as per the Fee Schedule. As such, you may want to charge your buyers and/or sellers fees also. Fees can be Fixed or Percentage based, and can be capped at a certain amount, with a minimum amount able to be set. Assembly customers use the fee engine in different ways. Some marketplace platforms choose to charge success fees to their sellers or credit card fees to their merchants, while other platforms pass on the credit card fee Assembly charges to their buyers.

The Assembly fee engine is a powerful, customizable tool designed to handle almost any business model your platform may require. Through a flexible approach, multiple fees can be applied to each transaction, along with the ability to apply fees to specific, individual items, allowing you to customize fees on a per user or per transaction basis.

Fee Calculation

Platforms fees are calculated in two ways:

Fixed Fees

A fixed fee is a set amount that you can charge your users per transaction.

Percentage Fees

A percentage fee is a varying, percentage based amount that you can charge your users per transaction. Variations on percentage fees:

  • Minimum fee

    A minimum fee is useful if your platform processes a large number of low-value transactions.

  • Capped fee

    A capped fee is useful if your platform process high-value transactions, but you don’t wish to charge your users a fee above a certain dollar amount.


Assembly handles the flow of funds from the buyer’s funding source, through to the seller’s nominated disbursement account. Throughout this funds transfer, the money never touches your platform’s bank account. We provide a mechanism for you to collect fees during the payment flow so that you only ever receive the fees you charge to provide your service, eliminating any perception that you might be the employer of the sellers on your platform.

Fee Types

Payment Method Surcharges

Assembly supports various payment methods. Assembly charges a fee based on the payment method used to fund the transaction. You as the platform can also create payment method surcharges to be added to the Item amount. The Fees API can be passed a parameter specifying to what the Fee should be applied. An example would be to set the = ‘cc’ parameter to charge the buyer a Credit Card surcharge.

Buyer / Seller Fees

Buyers and/or sellers can be charged a fee. The buyer fee will be added to the Item amount while the seller fees will be subtracted from the amount they receive.

Disbursement Fees

Fees can be charged for disbursements based on the disbursement account type.

Assembly Fees

As a service provider, Assembly charges fees on item transactions, which are calculated based on your marketplace’s existing fees as well as the surcharges incurred on payment method.

Receiving Fees

Fees are applied to Items. They will add or subtract from the Item amount based on the user (buyer or seller) or payment method. Fees are disbursed when the funds are released from Escrow, or when an Express transaction completes.


All of the fees are refunded when doing a full refund.

For partial refunds, a proportional amount is refunded for percentage fees. Fixed fees are not refunded for partial refunds.

Creating a Fee

You can create a fee within the Assembly API or within the Dashboard. If your fees are consistent, you may only need to create the fee once.

Billing Assembly fees

Assembly fees, like any other fees, are incurred automatically per transaction. However, if you prefer to have these fees billed on a schedule (for example, at month-end) instead of at time of transaction, you may request Assembly support to configure how your platform handles these fees.

Multiple-item workflow fees

Assembly fees are billed per item. Many integrations involve a multiple-item workflow which includes many items to move funds from a buyer to a seller (for example, crowdfunding). In these scenarios, Assembly charges a fee per item. This is seen as “double billing”, and in order for this to be avoided, you may request Assembly support to configure how your platform handles these fees.