JSON-RPC Reference

eth_subscribe

WebSocket required: eth_subscribe is only available over a persistent WebSocket connection (wss://). Starting **August 4, 2026 at 12:00 PM PST**, WebSocket connections require an authenticated Conduit account — append an API key to your WSS URL; anonymous connections are rejected. It cannot be used over HTTP and will fail against any HTTP endpoint. Use your Conduit WebSocket URL (wss://rpc-{chainSlug}.t.conduit.xyz/{apiKey}) with a WebSocket client such as websockets in Python, the native WebSocket in JavaScript, or gorilla/websocket in Go. Creates a subscription for real-time events. Supported subscription types include newHeads, logs, newPendingTransactions, and syncing. ⚡ Compute Units: [10 CU](https://docs.conduit.xyz/rpc-nodes/information/compute-units)

Request

This endpoint expects an object.
subscriptionTypeenumRequired
Type of subscription
Allowed values:
optionsobject or booleanOptional
Per-subscription-type options. Shape depends on `subscriptionType`: - `newHeads`: no options accepted. - `logs`: optional filter object `{address?, topics?}` mirroring the `Filter` shape minus `blockHash`/`fromBlock`/`toBlock`. `address` is a single address or array; `topics` is the positional array with single/array/null per position. - `newPendingTransactions`: optional boolean. When `true`, the notification payload includes the full transaction object instead of just the transaction hash. - `syncing`: no options accepted.

Response

Opaque subscription ID returned by the server. Pass this to eth_unsubscribe to cancel the subscription. Not a numeric quantity — treat as an opaque hex string.