> For the complete documentation index, see [llms.txt](https://docs.nexusglobalpayments.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nexusglobalpayments.org/payment-processing/payment-flow-happy-path/detailed-flow-in-source-country-sending.md).

# Detailed Flow in Source Country (Sending)

The sending payment process follows the following steps:

**4-step flow**

<figure><img src="/files/b8sQwkTK22Y9sIfMOxhx" alt=""><figcaption></figcaption></figure>

<table data-header-hidden data-full-width="false"><thead><tr><th width="73"></th><th></th><th></th></tr></thead><tbody><tr><td>#</td><td><strong>Process Step</strong></td><td><strong>Specific Requirements</strong></td></tr><tr><td>1</td><td>The <strong>Sender</strong> initiates and authorizes a Nexus cross-border payment.</td><td>The Sender has full transparency on the amount to be credited to the Recipient.</td></tr><tr><td>2</td><td>The <strong>Source PSP</strong> debits the Sender’s account or reserves the funds against the Sender's account balance.</td><td>The Source PSP must ensure the Sender has sufficient funds and must ensure the payment will be honoured, either by debiting the Sender’s account or by making a reservation of the funds on the account.</td></tr><tr><td>3</td><td>The <strong>Source PSP</strong> sends the payment instruction to the Source IPS.</td><td>There are no Nexus requirements on the format of the domestic payment message. The IPS must ensure the used payment message format contains sufficient data to cater for a Nexus payment message to be sent to the Nexus gateway. For full details of the Nexus requirements, see <a data-mention href="/pages/oJB9jylFPreVUefjfk3Y">/pages/oJB9jylFPreVUefjfk3Y</a></td></tr><tr><td>4</td><td>The <strong>Source IPS</strong> ensures settlement (by reserving the pre-funded balance of the Source PSP or otherwise).</td><td><p>The Source IPS must ensure settlement certainty. There is no requirement for Nexus how to do this (either by settling the transaction, making a reservation against a prefund or otherwise). (See <a data-mention href="/pages/cHTDbcs2RTxaq0W8BiYi">/pages/cHTDbcs2RTxaq0W8BiYi</a>.)</p><p>The Source IPS will also need to ensure a potential reject can be processed, even in the case of a settled transaction and in case of issues with other participants (eg lack of funds at the Source SAP, default of one of the participants, etc).</p></td></tr><tr><td>5</td><td>The <strong>Source IPS</strong> sends the payment instruction to the Source SAP for validation.</td><td></td></tr><tr><td>6</td><td>The <strong>Source SAP</strong> reviews the payment instruction. As this is a cross-border payment, it may need to also apply sanctions screening, if required by local legislation. </td><td></td></tr><tr><td>7</td><td>If the Source SAP is happy to accept the payment on behalf of the FXP (its customer), the Source SAP will respond with a payment status message to confirming that it will accept the payment.</td><td><p>Nexus does not prescribe the format of the domestic payment status confirmation message.</p><p>The IPS will monitor the response times of the Source SAP to ensure the response falls within the SLA.</p><p>In case of a reject, the IPS will release the reservation on the settlement and confirm the reject to the Source PSP.</p></td></tr><tr><td>8</td><td>The <strong>Source IPS</strong> sends a Nexus <code>pacs.008</code> payment instruction message to <strong>Nexus.</strong></td><td><p>Unlike a domestic payment, the Source IPS would not send a confirmation to the Source PSP yet. Instead, it waits to receive the response from Nexus.</p><p>Some IPSs may still choose to send a <code>pacs.002</code> with a status code that informs the PSP that the payment has successfully been sent to Nexus. This would be at the discretion of the IPS and is not required or specified by Nexus.<br><br>If the Source IPS does not use the Nexus ISO 20022 messages domestically, it needs to translate them at this point.</p></td></tr><tr><td>9</td><td><p>The <strong>Nexus</strong> validates and transforms the payment instruction to prepare it for the second leg by:</p><ul><li>changing the instructing and instructed agents to the Destination SAP and Destination PSP respectively</li><li>validating the quote that is referenced, updating the currency and applying the currency conversion to the “Interbank Settlement Amount”.</li></ul><p><strong>Nexus</strong> then forwards the payment instruction to the Destination IPS.</p></td><td></td></tr><tr><td>10</td><td>The Nexus <code>pacs.008</code> is processed on the Destination side</td><td>(See <a data-mention href="/pages/PXCAXP0K7Ri64hzfpS8k">/pages/PXCAXP0K7Ri64hzfpS8k</a> for more details.)</td></tr><tr><td>11</td><td>The Destination Nexus Gateway sends the result from the Destination IPS processing in a Nexus <code>pacs.002</code> payment status report to the Source Nexus Gateway</td><td></td></tr><tr><td>12</td><td>The Source Nexus Gateway forwards the <code>pacs.002</code> payment status report message to the Source IPS.</td><td>If the Source IPS does not use ISO 20022 to communicate with its participants, it may translate the <code>pacs.002</code> at this point.</td></tr><tr><td>13</td><td><p>The <strong>Source Gateway</strong> informs the <strong>FXP</strong> that a payment has been processed using their quote; this is important to enable the FXP to keep track of their liquidity.</p><p>The FXP may also be separately updated of their account balances by the Source SAP and Destination SAP.</p></td><td></td></tr><tr><td>14</td><td>The Source IPS will finalise the payment between the Source PSP and Source SAP by updating the settlement obligations.</td><td></td></tr><tr><td>15</td><td>The Source IPS will send the Source PSP a confirmation that the payment has been successful.</td><td></td></tr><tr><td>16</td><td>The Source PSP can no finalize the debit on the Sender's account</td><td></td></tr><tr><td>17</td><td>The <strong>Source PSP</strong> informs their <strong>Sender</strong> that the payment is complete.</td><td></td></tr><tr><td>18</td><td>In case of a reject, the Source IPS will undo the settlement reservation.</td><td></td></tr><tr><td>19</td><td>The Source IPS informs the Source SAP the payment has been rejected and the credit on the FXP account must be reversed.</td><td></td></tr><tr><td>20</td><td>The Source IPS informs the Source PSP the payment is rejected</td><td></td></tr><tr><td>21</td><td>The Source SAP reverses the credit on the FXPs account</td><td></td></tr><tr><td>22</td><td>The Source PSP releases the reservation on the Senders account, or, in case the account was debited, credits the account with the exact amount it was debited.</td><td></td></tr><tr><td>23</td><td>The Source PSP informs the Sender of the reject.</td><td></td></tr></tbody></table>

**5-step flow**

<figure><img src="/files/UEUfIwbyxQA21F46QiFN" alt=""><figcaption></figcaption></figure>

<table data-header-hidden data-full-width="false"><thead><tr><th width="73"></th><th></th><th></th></tr></thead><tbody><tr><td>#</td><td><strong>Process Step</strong></td><td><strong>Specific Requirements</strong></td></tr><tr><td>1</td><td>The <strong>Sender</strong> initiates and authorizes a Nexus cross-border payment.</td><td>The Sender has full transparency on the amount to be credited to the Recipient.</td></tr><tr><td>2</td><td>The <strong>Source PSP</strong> debits the Sender’s account or reserves the funds against the Sender's account balance.</td><td>The Source PSP must ensure the Sender has sufficient funds and must ensure the payment will be honoured, either by debiting the Sender’s account or by making a reservation of the funds on the account.</td></tr><tr><td>3</td><td>The <strong>Source PSP</strong> sends the payment instruction to the Source IPS.</td><td>There are no Nexus requirements on the format of the domestic payment message. The IPS must ensure the used payment message format contains sufficient data to cater for a Nexus payment message to be sent to the Nexus gateway. For full details of the Nexus requirements, see <a data-mention href="/pages/oJB9jylFPreVUefjfk3Y">/pages/oJB9jylFPreVUefjfk3Y</a></td></tr><tr><td>4</td><td>The <strong>Source IPS</strong> ensures settlement (by reserving the pre-funded balance of the Source PSP or otherwise).</td><td><p>The Source IPS must ensure settlement certainty. There is no requirement for Nexus how to do this (either by settling the transaction, making a reservation against a prefund or otherwise). (See <a data-mention href="/pages/cHTDbcs2RTxaq0W8BiYi">/pages/cHTDbcs2RTxaq0W8BiYi</a>.)</p><p>The Source IPS will also need to ensure a potential reject can be processed, even in the case of a settled transaction and in case of issues with other participants (eg lack of funds at the Source SAP, default of one of the participants, etc).</p></td></tr><tr><td>5</td><td>The <strong>Source IPS</strong> sends the payment instruction to the Source SAP for validation.</td><td></td></tr><tr><td>6</td><td>The <strong>Source SAP</strong> reviews the payment instruction. As this is a cross-border payment, it may need to also apply sanctions screening, if required by local legislation.</td><td></td></tr><tr><td>7</td><td>If the Source SAP is happy to accept the payment on behalf of the FXP (its customer), the Source SAP will respond with a payment status message to confirming that it will accept the payment.</td><td><p>Nexus does not prescribe the format of the domestic payment status confirmation message.</p><p>The IPS will monitor the response times of the Source SAP to ensure the response falls within the SLA.</p><p>In case of a reject, the IPS will undo the reservation and confirm the reject to the Source PSP.</p></td></tr><tr><td>8</td><td>The <strong>Source IPS</strong> sends a Nexus <code>pacs.008</code> payment instruction message to <strong>Nexus.</strong></td><td><p>Unlike a domestic payment, the Source IPS would not send a confirmation to the Source PSP or Source SAP yet. Instead, it waits to receive the response from Nexus.</p><p>Some IPSs may still choose to send a <code>pacs.002</code> with a status code that informs the PSP that the payment has successfully been sent to Nexus. This would be at the discretion of the IPS and is not required or specified by Nexus.<br><br>If the Source IPS does not use the Nexus ISO 20022 messages domestically, it needs to translate them at this point.</p></td></tr><tr><td>9</td><td><p>The <strong>Nexus</strong> validates and transforms the payment instruction to prepare it for the second leg by:</p><ul><li>changing the instructing and instructed agents to the Destination SAP and Destination PSP respectively</li><li>validating the quote that is referenced, updating the currency and applying the currency conversion to the “Interbank Settlement Amount”.</li></ul><p><strong>Nexus</strong> then forwards the payment instruction to the Destination IPS.</p></td><td></td></tr><tr><td>10</td><td>The Nexus <code>pacs.008</code> is processed on the Destination side</td><td>(See <a data-mention href="/pages/PXCAXP0K7Ri64hzfpS8k">/pages/PXCAXP0K7Ri64hzfpS8k</a> for more details.)</td></tr><tr><td>11</td><td>The Destination Nexus Gateway sends the result from the Destination IPS processing in a Nexus <code>pacs.002</code> payment status report to the Source Nexus Gateway</td><td></td></tr><tr><td>12</td><td>The Source Nexus Gateway forwards the <code>pacs.002</code> payment status report message to the Source IPS.</td><td>If the Source IPS does not use ISO 20022 to communicate with its participants, it may translate the <code>pacs.002</code> at this point.</td></tr><tr><td>13</td><td><p>The <strong>Source Gateway</strong> informs the <strong>FXP</strong> that a payment has been processed using their quote; this is important to enable the FXP to keep track of their liquidity.</p><p>The FXP may also be separately updated of their account balances by the Source SAP and Destination SAP.</p></td><td></td></tr><tr><td>14</td><td><p>The Source IPS will finalise the payment between the Source PSP and Source SAP by updating the settlement obligations.</p><p></p></td><td></td></tr><tr><td>15</td><td>The Source IPS will send the Source SAP a confirmation that the payment has been successful.</td><td></td></tr><tr><td>16</td><td>The Source IPS will send the Source PSP a confirmation that the payment has been successful.</td><td></td></tr><tr><td>17</td><td>The Source SAP credits the FXP account.</td><td></td></tr><tr><td>18</td><td>The Source PSP debits the Senders account.</td><td></td></tr><tr><td>19</td><td>The <strong>Source PSP</strong> can now inform their <strong>Sender</strong> that the payment is complete.</td><td></td></tr><tr><td>20</td><td>In case of a reject, the Source IPS will undo the settlement reservation.</td><td></td></tr><tr><td>21</td><td>The Source IPS informs the Source SAP of the rejected payment via a pacs.002</td><td></td></tr><tr><td>22</td><td>The Source IPS informs the Source PSP of the rejected payment via a pacs.002</td><td></td></tr><tr><td>23</td><td>The Source PSP releases the hold on the Senders account.</td><td></td></tr><tr><td>24</td><td>The Source PSP informs the Sender of the reject.</td><td></td></tr></tbody></table>