build-data-pipeline

Start with Helius webhooks to receive parsed transaction events at your endpoint, then write them idempotently into PostgreSQL using the transaction signature as a deduplication key. Add a backfill routine using the Helius transaction history API to recover any missed events.

Webhooks are the simplest option with roughly 200-500ms latency and no infrastructure to maintain. WebSocket subscriptions like accountSubscribe offer lower latency and more control but require managing a persistent connection and reconnection logic.

Use the transaction signature as a natural deduplication key with an INSERT ... ON CONFLICT DO NOTHING statement in PostgreSQL. Webhooks and WebSockets can deliver duplicates, so every write path must be idempotent.

PostgreSQL is the standard choice for structured indexed data, using JSONB for raw payloads and NUMERIC for token amounts that overflow BIGINT. Redis works as a caching layer for hot data like token prices and real-time leaderboards.

Paginate through the Helius address transaction history API using the before-signature parameter, feeding each transaction through the same idempotent handler used by your webhook. This recovers events lost during deploys, restarts, or outages.

The slot is the source of truth for ordering on Solana and enables deduplication, gap detection, and lag monitoring. Without it you cannot reliably detect missing data or measure how far behind your pipeline has fallen.