Develop Stellar/Soroban Event Listener Indexer Service

[Luluameh]

• Labels: backend, indexer, stellar, soroban

Description

To keep the database in sync with on-chain interactions, we need a backend service that polls the Stellar Horizon / Soroban RPC endpoint for events emitted by our Escrow and Dispute smart contracts.

Technical Scope & Steps

1. Set up a polling interval script using the @stellar/stellar-sdk to monitor ledger state.
2. Filter transaction events by contract ID and event topics (e.g., fund_session, pause_session, refund_session, complete_session).
3. Decode contract XDR event payloads into readable JSON data.
4. Update the corresponding Session and Transaction status in the PostgreSQL database based on event content.
5. Track and store the last processed ledger sequence to prevent double-processing or missed sequences on restart.

Acceptance Criteria

• Simulating a contract event triggers the database update within 5 seconds.
• Restarts continue processing from the last saved ledger sequence.
• Failures in decoding event payloads do not crash the service.

[devchant]

Hi, I’d like to work on this issue.

I have experience building full-stack applications with TypeScript, Node.js, PostgreSQL, APIs, and blockchain integrations. Since SkillSphere already uses Stellar and Soroban for real-time payments, I understand the importance of having a reliable indexer that keeps on-chain contract activity synchronized with the application database.

My proposed approach would be to:

• Connect the service to the configured Stellar/Soroban RPC endpoint.
• Subscribe to or periodically retrieve relevant SkillSphere contract events.
• Decode and normalize events such as session creation, payment streaming, escrow settlement, cancellation, and refunds.
• Store processed events and the latest synchronized ledger in PostgreSQL.
• Add idempotency checks to prevent duplicate event processing.
• Implement retry handling, structured logging, and recovery from RPC or network failures.
• Backfill missed events when the service restarts.
• Add unit and integration tests for event parsing, duplicate prevention, checkpoint recovery, and failure scenarios.
• Provide clear environment setup and documentation for running the indexer locally.

I will keep the implementation modular so additional Soroban contracts and event types can be added easily in the future.

Please assign this issue to me.

[grantfox-oss]

🦊 GrantFox — @devchant has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #3)
2. Your PR will be reviewed by the LightForgeHub maintainers

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