Websocket Event Subscriptions

Instead of repeatedly requesting data from RPC endpoints, your application keeps a persistent bidirectional connection and the server pushes events to your client as they happen. This removes polling loops, reduces wasted requests, and keeps your application in sync with current chain state.

Because WebSockets are natively supported by browsers and virtually every language ecosystem, they are the easiest way to consume real-time blockchain data. No gRPC tooling, Protobuf schemas, or code generation required.

WebSocket Pricing

What this page covers

This guide explains when WebSocket subscriptions are the right choice for real-time blockchain data, how they compare to HTTP polling and gRPC streaming, and what to plan for in production.

Why Use WebSockets for Blockchain Data

WebSockets hit the sweet spot between simplicity and real-time capability. They deliver push-based updates like gRPC streaming, but over a protocol your stack already speaks.

Key Benefits

• Real-time push delivery
  Receive events the moment they occur on-chain, with no polling intervals
• Standard web protocol
  Native support in browsers, Node.js, Python, Go, and every major language, with no special tooling
• Server-side filtering
  Subscribe only to the addresses, programs, contract events, or transaction types you care about
• Human-readable payloads
  JSON messages that are easy to inspect, debug, and process
• Subscriptions and queries on one connection
  On EVM chains, execute standard JSON-RPC calls over the same socket used for subscriptions
• Auto-cleanup
  Subscriptions close automatically when the connection drops, with no orphaned server state

Common Use Cases

WebSocket subscriptions are ideal for applications that need live updates at moderate volume:

• Wallet frontends tracking balances and transaction confirmations
• Block explorers and real-time dashboards
• DeFi interfaces reacting to swaps, liquidations, and pool changes
• NFT marketplaces monitoring mints, listings, and sales
• Mempool monitoring and gas price tracking (EVM chains)
• Notification services triggering alerts on on-chain activity

Supported Chains

Tatum currently offers WebSocket subscriptions on three chains. Each implements its native PubSub interface:

WebSocket vs. HTTP Polling

Traditional RPC APIs require constant polling to detect changes, which introduces latency and wasted requests. WebSockets remove this limitation by pushing data directly to your application.

Recommendation:

• Use WebSocket for: real-time dashboards, wallet UIs, event-driven architectures, transaction confirmation tracking.
• Use HTTP RPC for: serverless functions, one-off queries, simple scripts, environments where persistent connections aren't possible.

WebSocket vs. gRPC Streaming

Both deliver push-based real-time data. The right choice depends on your throughput needs and operational constraints:

Recommendation:

• Use WebSocket for: frontends, prototyping, transaction confirmations, and moderate-volume event monitoring.
• Use gRPC Data Streams for: indexers, high-frequency trading, analytics, and high-volume ingestion.

Operational Best Practices

For production-grade WebSocket consumers, implement:

• Automatic reconnection with exponential backoff
• Resubscription logic on reconnect, since subscriptions do not survive a dropped connection
• Backfill after gaps, for example using eth_getLogs or equivalent historical queries to recover events missed while disconnected
• Idempotent downstream processing to handle duplicate deliveries safely
• Heartbeat or ping/pong handling to detect stale connections early
• Monitoring for disconnect rates, message lag, and subscription health

Common pitfalls

Avoid these implementation issues:

• Assuming subscriptions persist across reconnects; they must be re-established every time
• Skipping backfill logic and silently missing events that occurred during a disconnect
• Processing notifications synchronously in one hot path without buffering
• Ignoring subscription confirmation IDs, which are needed to route notifications and unsubscribe cleanly

Next steps

To start streaming on a supported chain, visit the reference documentation:

• Solana WebSocket Reference
• Ethereum WebSocket Reference
• Polygon WebSocket Reference