[Soroban] Payment reference (memo) validation in contract

[Xaxxoo]

Overview

Store the expected payment memo in the contract and validate that incoming deposits reference it correctly, preventing funds from being credited to the wrong payment.

Tasks

• Store memo: Bytes per payment in contract storage
• Add validate_memo(payment_id, memo) view function
• NestJS calls validate_memo before confirming payment
• Return error code for memo mismatch
• Unit test mismatched and correct memo scenarios

Acceptance Criteria

• Deposits with wrong memo cannot be confirmed
• NestJS double-checks memo via contract before DB update

[menawar]

@menawar has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

can i work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @menawar to this issue.

[drips-wave]

Congratulations, @menawar! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

🧑‍💻 @menawar: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊