Building a blockchain indexer on AWS

This article describes how to build a blockchain indexer on AWS to efficiently query blockchain data for DeFi applications.

• Blockchain indexers transform sequential blockchain data into queryable formats via secondary databases
• Two indexing modes: backfilling (historical data) and forward filling (real-time with reorg awareness)
• Architecture uses Amazon MSK for intermediary storage, Apache Flink for transformation, Amazon RDS for final storage
• Backfilling uses cryo extraction engine with parallel RPC calls for fast historical data ingestion
• Forward filling monitors new blocks and handles chain reorganizations by rewinding to common ancestor
• Reth client's Execution Extensions feature enables reorg-aware real-time data streaming to Kafka
• Separation of extraction from transformation allows logic changes without re-querying blockchain node
• Multiple Flink consumers can run in parallel to filter and transform data independently

This AWS-based solution provides scalable, efficient blockchain data indexing by decoupling extraction from transformation and maintaining real-time consistency through reorg awareness.