> ## Documentation Index
> Fetch the complete documentation index at: https://docs.debridge.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Order Fulfillment

> Order fulfillment steps, solver transactions, and cost considerations for DLN orders.

This page outlines secondary but relevant concepts related to order creation. While not central to the core flow for creating an order,
they are important for transparency and for understanding various fields in the create-tx API response.

Order fulfillment involves three distinct steps:

* Detecting the created order on the source chain
* Fulfilling the order on the destination chain
* Claiming the order on the source chain

In total, a solver performs three transactions during the lifecycle of an order:

* Fulfilling the order on the destination chain
* Sending unlock message via DMP from destination to the source chain
* Claiming the locked order input assets on the source chain

The gas fees associated with those transactions are considered operating costs and should be factored in when creating an order.

```mermaid theme={null}
sequenceDiagram
    actor Solver
    participant DlnSource
    participant SimulateService
    participant DlnDestination
    participant SwapService
    participant DMP
    actor Beneficiary
    Beneficiary ->> DlnSource : CreateOrder()
    rect rgba(240, 240, 240, .15)
    note right of Solver: Simulate Order 
    DlnSource ->> Solver : CreatedOrder(orderId)
    Solver ->> SimulateService : simulateOrder(orderId)
    activate SimulateService
    SimulateService -->> Solver : simulationResult
    deactivate SimulateService
    end 
    alt not simulationResult.profitable
        note right of Solver: Order Ignored
    else simulationResult.profitable
        rect rgba(240, 240, 240, .15)
            note right of Solver: Fulfil Order (Destination Chain)
            Solver ->> DlnDestination : fulfillOrder(...) with reserve assets
            activate DlnDestination
            alt reserveAssetsWanted == false
                note right of DlnDestination: Pre-Fill Swap
                DlnDestination ->> SwapService : swapReserveToWanted()
                activate SwapService
                SwapService -->> DlnDestination : wantedAssets
                deactivate SwapService
            else
                note right of DlnDestination: No swap needed
            end
            DlnDestination ->> Beneficiary : transferWantedAssets(amount)
            DlnDestination -->> Solver     : fulfilReceipt
            deactivate DlnDestination
        end
        rect rgba(240, 240, 240, .15)
          note right of Solver: Send Unlock
          Solver ->> DMP : sendCrossChainMessage(orderId)
          activate DMP
          DMP -->> Solver : ack
          DMP ->> DlnSource : unlockOrder
          deactivate DMP
        end
        rect rgba(230, 230, 255, .15)
            note right of Solver: Claim Input Assets
            Solver     ->> DlnSource : claimOrder(...)
            activate DlnSource
            DlnSource -->> Solver     : claimReceipt
            deactivate DlnSource
        end
    end
```