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The indexer keeps the backend in sync with onchain state so the relayer can resolve accounts quickly.

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Why It Exists

Without the indexer, every authenticated request would require the relayer to scan the onchain AccountRegistry to find which MemWalAccount holds a given delegate key. This involves fetching the registry object, iterating through its dynamic fields, and checking each account — an expensive chain of RPC calls. The indexer eliminates this by listening to Sui events and syncing account data into PostgreSQL. The relayer can then resolve delegate key ownership with a single database lookup.

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How It Works

The indexer is a standalone Rust service (services/indexer) that:
  1. Connects to the same PostgreSQL database as the relayer
  2. Polls Sui blockchain events using suix_queryEvents
  3. Filters for AccountCreated events from the MemWal package
  4. Inserts account_id → owner mappings into the accounts table
  5. Stores its event cursor in indexer_state so it can resume after restarts

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Auth Resolution Flow

When the relayer receives a request, it resolves the delegate key’s account using this priority:
  1. PostgreSQL cache (delegate_key_cache) — fastest, populated lazily by the relayer itself
  2. Indexed accounts (accounts) — populated by the indexer, enables account discovery without chain scans
  3. Onchain registry scan — fallback, scans AccountRegistry dynamic fields via RPC
  4. Header hint (x-account-id) — client-provided hint, useful during first-time setup
  5. Config fallback (MEMWAL_ACCOUNT_ID) — server-level default
After successful resolution through any strategy, the mapping is cached in delegate_key_cache for future requests.

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Configuration

The indexer reads these environment variables:
VariableRequiredDefaultDescription
DATABASE_URLYes—PostgreSQL connection string
MEMWAL_PACKAGE_IDYes—MemWal contract package ID to filter events
SUI_RPC_URLNoMainnet fullnodeSui RPC endpoint
POLL_INTERVAL_SECSNo5Seconds between event poll cycles

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Running

cd services/indexer
cargo run
The indexer is recommended for production but optional for development — the relayer can fall back to onchain resolution without it.