[Feature]: Stellar micro-payments module

[memplethee-lab]

Feature Request

Problem Statement

The repository lacks a Stellar micro-payments module to enable low-fee, fast microtransactions for grant disbursements, tipping, and reward payouts. Without a native Stellar module, teams must implement ad-hoc payment logic, increasing engineering effort and risk.

Proposed Solution

Add a Stellar micro-payments module that:

• Provides REST endpoints to create, sign, and submit Stellar transactions (SEP-000X compatible), including support for testnet and mainnet.
• Supports creating client-side signed transactions and server-side anchors for asset issuance.
• Implements idempotent payment submission, fund source selection, and rate limiting to prevent accidental double-spend.
• Exposes reconciliation endpoints and webhooks for Stellar payment events (using Horizon streaming or webhook anchors).

Acceptance criteria:

• Module exposes documented endpoints: /payments/stellar/create, /payments/stellar/submit, /payments/stellar/status.
• Transactions can be created and submitted on testnet in CI with sample keys.
• Idempotency keys prevent double-processing of the same logical payment.
• End-to-end tests simulate a payment from a funded testnet account to a recipient and assert ledger inclusion.

Alternatives Considered

• Using third-party payment providers (rejected: adds external fees and centralization).
• Off-chain ledger with batched on-chain settlements (future enhancement).

Additional Context

Stellar is attractive for Grantfox and Stellar teams due to low fees and fast finality — implementing native support will make the API competitive for micropayments.

Implementation Ideas (Optional)

• Use stellar-sdk and Horizon testnet for integration tests. Implement a StellarService abstraction and a PaymentsController.

Would you be willing to contribute?

• Yes, I'd like to submit a PR for this feature
• I can help with testing
• I can help with documentation
• I'd rather let someone else work on this

[Peculiarr7]

Hi! I’m a full-stack developer with a strong blockchain background, and I’m confident I can resolve this issue quickly and effectively. I’ll deliver a clean, reliable solution with immediate attention to detail, ensuring it’s completed as soon as possible. Please assign it to me—I’m ready to get started right away.

[bobo-24]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. I’ll prioritize this immediately and ensure a reliable solution is delivered as soon as possible. Thank you!

[ayaanoncrypto]

I have reviewed issue #143 and the payment-module requirements. I will trace the existing API and Stellar integrations, implement create, submit, and status endpoints with testnet and mainnet configuration, idempotency protection, safe fund-source handling, rate limits, Horizon event reconciliation, and webhook support. I will add focused unit tests and a funded testnet integration path covering ledger inclusion and duplicate-payment prevention. I can start immediately and deliver a working PR within one hour.

[Yasir-TechGuy]

Hi Mantainer, I will like to work on this issue

[akargi]

Hi Maintainer,

I’m a full-stack developer, and I’d like to contribute to the task. I’ll implement it carefully and efficiently thoroughly understand requirements and edge cases
Communicate promptly about suggestions or improvements. And I will provide regular progress updates and address blockers
Align with project goals through feedback and clarification.

Thank you,

[grantfox-oss]

🦊 GrantFox — @akargi has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #143)
2. Your PR will be reviewed by the SourceXXL maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Third Campaign campaign!

@akargi's PR #150 was approved and merged by @memplethee-lab.

🏆 @akargi: You earned 40 FoxPoints for this contribution! Your current tier: Builder (1,105 total points). Track your full progress on GrantFox.

👏 Great work, @akargi! Keep contributing to SourceXXL.