Adapter Contract#

Every provider in Artery implements the same IPredictionMarketProvider interface (@artery/types). Capabilities (data / trade / stream / delegation) are declared per-provider and surfaced via GET /providers.

Wire format#

All Endpoints return the native passthrough shape:

json{
  "native": {
    /* raw upstream JSON, unmodified */
  },
  "meta": {
    "provider": "polymarket",
    "fetchedAt": "2026-05-05T07:30:00.000Z",
    "source": "live"
  }
}

Capability matrix#

Self-hosted source: Hyperliquid#

The Hyperliquid adapter is the first one running in "indexed" mode in production. Artery operates its own Hyperliquid non-validator node (hl-visor) on dedicated hardware, paired with hl-adapter — a small Go service that:

1. Tails node_fills_by_block/hourly/<day>/<hour> + misc_events_by_block/... files and indexes them into Postgres (hl_fills, hl_misc_events)
2. Serves the /info API on the same JSON contract as api.hyperliquid.xyz — locally for the supported types, transparently passing through for anything else
3. Caches HL official passthrough responses in an in-memory LRU per-type so repeat calls inside the cache TTL never re-hit the public API

Net effect for clients: zero rate-limit + sub-millisecond latency for the locally-served /info types (allMids, candleSnapshot, meta, spotMeta, clearinghouseState, userFills, userFillsByTime, userFunding, userNonFundingLedgerUpdates, openOrders, subAccounts, delegations), with full HL outage immunity for those endpoints. See providers/hyperliquid for the customer-facing catalog + caveats.

The other providers (Polymarket, Kalshi) still route through public API + RPC. Same indexing pattern can be applied later if scale or cost justifies it.

Two-implementation pattern#

Each adapter has two implementations sharing one interface:

• Live — calls upstream API directly via @artery/transport
• IndexedDB — A future release will read from our own RPC node + indexer

tsconst polymarketAdapter = createPolymarketAdapter({
  source:
    ART_SOURCE === 'indexed'
      ? new IndexedPolymarketSource(redis, postgres) // indexed source (roadmap)
      : new LivePolymarketSource(transport), // live source
});

A single contract test suite (apps/api/test/contract/) runs against both implementations, guaranteeing equivalence at switchover.