spike: indexer research for stellar

[RafaDSan]

As we need to index data from the stellar smart contracts, we have the options to do it manually, building our own indexing system or integrate it with an alrerady builded indexer.

Research the following indexers: https://developers.stellar.org/docs/data/data-indexers/indexer-providers

Checklist:

Indexer Functionality

• Does it support Soroban?
• Does it have Real-time event capture capability?
• Does it have Historical data retrieval support?
• Does it have Support for custom event filtering?
• Does it have Ability to handle contract-specific events?
• Does it have Error handling and recovery mechanisms?

Integration Requirements (Optional as depending on the indexer it will have the whole process)

• Does it have API compatibility with our backend (NestJS)?
• Does it have Documentation quality and completeness?
• Does it have SDK availability for our tech stack?

Performance Considerations:

• Is the average query response time viable?
• Is the average Data freshness (lag time) time viable?
• Are the Scalability options viable?

Cost Analysis:

• How is the Pricing model (pay-per-use, subscription)?
• How are the Free tier limitations?
• How much is the Pricing for additional features?
• How is the Support costs?
• Infrastructure costs if self-hosted

Support & Maintenance:

• How is the Community activity
• How is the Technical support availability
• How is the Bug fix responsiveness

[RafaDSan]

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