Websocket API Guide for OKTC

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OKTC leverages Tendermint Core as its consensus engine and is built using the Cosmos SDK framework. While this provides a robust foundation, OKTC also ensures compatibility with Ethereum's Web3 standards—specifically for websocket communications via the Ethereum PubSub API. This requires converting Tendermint responses into Ethereum-compatible data types.

Getting Started with Websockets

To initiate a connection with the Ethereum websocket, use the --wsport flag when starting the REST server (default port: 8546).

Example:

rest-server --wsport 8546

Once the server is running, you can establish a websocket subscription using clients like ws or similar tools.

Websocket URLs

Mainnet Endpoint

wss://mainnet.oktc.io/websocket

Managing Subscriptions

Creating a Subscription

Use the RPC method eth_subscribe with the subscription name and optional arguments.

Parameters:

  1. Subscription Name (e.g., newHeads, logs).
  2. Optional Arguments (e.g., filter criteria for logs).

Example Request:

{
  "method": "eth_subscribe",
  "params": ["newHeads"]
}

Response: Returns a unique subscription ID.

Canceling a Subscription

Use the RPC method eth_unsubscribe with the subscription ID.

Parameters:

  1. Subscription ID (returned during creation).

Example Request:

{
  "method": "eth_unsubscribe",
  "params": ["0x9b13452..."]
}

Response: Returns true if canceled successfully.

Supported Subscription Types

1. newHeads

Notifies when a new block header is added to the chain (includes reorganizations).

Parameters: None.

Example Output:

{
  "header": { ... },
  "removed": false
}

2. logs

Emits logs from new blocks matching specified filters. Resends logs from orphaned blocks with removed: true.

Parameters:

Example Request:

{
  "method": "eth_subscribe",
  "params": ["logs", { "address": "0x123...", "topics": ["0xaabb..."] }]
}

3. newPendingTransactions

Returns hashes of signed transactions added to the pending state.

Parameters: None.

Example Output:

"0x5e9abc92..."

4. syncing

Indicates synchronization status (boolean or progress object).

Example Output:

{
  "syncing": true,
  "currentBlock": "0x1234",
  "highestBlock": "0x5678"
}

FAQ

Q1: How do I troubleshoot a failed subscription?

A: Verify the websocket URL and port. Check if the subscription parameters match the supported formats.

Q2: Can I subscribe to multiple events simultaneously?

A: Yes, each subscription requires a separate eth_subscribe call.

Q3: Why are logs duplicated after a reorganization?

A: The protocol resends logs from orphaned blocks with removed: true and emits new chain logs.

👉 Explore advanced websocket configurations for real-time data handling.

Key Terms: OKTC websocket, Ethereum PubSub API, Tendermint events, eth_subscribe, blockchain synchronization, real-time logs, pending transactions.