# WebSocket streaming

> HyperCore private-preview documentation.

> For the complete documentation index, see [llms.txt](/docs/llms.txt).

<Callout intent="info">
  This API is in private preview. Target September 2026; timing is subject to change.
</Callout>


# WebSocket streaming

## Subscription envelope

Use the native subscription envelope: `{"method":"subscribe","subscription":{...}}`. Use the same subscription object with `"method":"unsubscribe"` to close a stream. Acknowledgements use `"channel":"subscriptionResponse"`; data frames use `{"channel":"<type>","data":{...}}`.

HyperCore data frames carry additive top-level metadata: `subscriptionId`, `blockHeight`, `blockTime`, and, on replay-capable streams, `cursor`.

## Envelope fields

| Field | Type | Description |
| --- | --- | --- |
| channel | string | Subscription-response channel or stream type. |
| data | object | Stream-specific payload. |
| subscriptionId | string | Subscription identifier. |
| blockHeight | integer | Source-block height. |
| blockTime | integer | Source-block time. |
| cursor | string | Opaque resume token on replay-capable streams. |

## Subscription fields

Native subscriptions use singular `coin` and `user` fields. HyperCore's `coins`, `users`, `builders`, `intervals`, and `eventTypes` arrays are Alchemy extensions for multi-entity subscriptions. Candle subscriptions include both a coin dimension and an interval dimension.

## Stream catalog

| Stream | Description |
| --- | --- |
| [activeAssetCtx](/docs/chains/websockets/hypercore/streams/active-asset-context) | Active asset context. |
| [allCandles](/docs/chains/websockets/hypercore/streams/all-candles) | Candle updates across selected coins and intervals. |
| [allFills](/docs/chains/websockets/hypercore/streams/all-fills) | Fill updates across selected coins. |
| [allIsolatedMarginUpdates](/docs/chains/websockets/hypercore/streams/all-isolated-margin-updates) | Isolated-margin updates across the available stream scope. |
| [allLeverageUpdates](/docs/chains/websockets/hypercore/streams/all-leverage-updates) | Leverage-setting updates across the available stream scope. |
| [allTwapStatusUpdates](/docs/chains/websockets/hypercore/streams/all-twap-status-updates) | TWAP-status updates. |
| [allUserNonFundingLedgerUpdates](/docs/chains/websockets/hypercore/streams/all-user-non-funding-ledger-updates) | Non-funding ledger updates. |
| [bbo](/docs/chains/websockets/hypercore/streams/bbo) | Best-bid and offer book updates. |
| [builderFills](/docs/chains/websockets/hypercore/streams/builder-fills) | Builder fill updates. |
| [builderLiquidation](/docs/chains/websockets/hypercore/streams/builder-liquidation) | Builder-context liquidation updates. |
| [builderOrderUpdates](/docs/chains/websockets/hypercore/streams/builder-order-updates) | Builder order updates. |
| [candles](/docs/chains/websockets/hypercore/streams/candles) | Candle updates for selected coins and intervals. |
| [fundingRates](/docs/chains/websockets/hypercore/streams/funding-rates) | Funding-rate updates. |
| [l2Book](/docs/chains/websockets/hypercore/streams/l2-book) | L2 book snapshots. |
| [l2BookDiff](/docs/chains/websockets/hypercore/streams/l2-book-diff) | L2 book differences. |
| [l4BookUpdates](/docs/chains/websockets/hypercore/streams/l4-book-updates) | L4 order-level updates. |
| [liquidationFills](/docs/chains/websockets/hypercore/streams/liquidation-fills) | Liquidation fill updates. |
| [setOracleUpdates](/docs/chains/websockets/hypercore/streams/set-oracle-updates) | Oracle updates. |
| [tpslUpdates](/docs/chains/websockets/hypercore/streams/tpsl-updates) | Take-profit and stop-loss updates. |
| [trades](/docs/chains/websockets/hypercore/streams/trades) | Market-wide trade events; use userFills for the same events scoped to an account. |
| [userFills](/docs/chains/websockets/hypercore/streams/user-fills) | User fill updates. |
| [userIsolatedMarginUpdates](/docs/chains/websockets/hypercore/streams/user-isolated-margin-updates) | User-context isolated-margin updates. |
| [userLeverageUpdates](/docs/chains/websockets/hypercore/streams/user-leverage-updates) | User-context leverage updates. |
| [userNonFundingLedgerUpdates](/docs/chains/websockets/hypercore/streams/user-non-funding-ledger-updates) | User non-funding ledger updates. |
| [userOrderUpdates](/docs/chains/websockets/hypercore/streams/user-order-updates) | User order updates. |

For connection, resume, and recovery behavior, see [connection lifecycle](/docs/chains/websockets/hypercore/connection-lifecycle) and [replay and recovery](/docs/chains/websockets/hypercore/replay-and-recovery).