Key Takeaways
Binance WebSockets enable real-time data exchange but require adherence to limits such as rate, weight, and connection restrictions to avoid disruptions.
Implementing robust error-handling mechanisms, such as automatic reconnections and proper JSON formatting, is critical for maintaining connections. For instance, a reconnection strategy can involve exponential backoff and immediate reauthentication upon disconnect.
Users should leverage endpoints like exchangeInfo to monitor rate limits effectively. Integrating this data into dashboards or alert systems can help proactively avoid temporary bans or disconnections.
Introduction
Websockets enable real-time bidirectional communication, making them essential for applications such as cryptocurrency trading. Binance offers WebSocket APIs and WebSocket streams to facilitate real-time market data retrieval and order management. However, these tools come with specific usage limits and error-handling requirements.
This article explores the key limitations of Binance WebSockets, common errors encountered while using them, and strategies to handle these errors effectively. The information presented here is based primarily on Binance's official API documentation.
WebSocket Limits
Binance imposes several types of limits on WebSocket usage to ensure the stability and fairness of its platform. These limits apply to both WebSocket streams and the WebSocket API or either of them.
Ping/Pong Mechanism: Keeping WebSocket Connections Active
The Ping/Pong protocol ensures that WebSocket connections remain active. After a connection is established, the Binance server sends a Ping frame every three minutes to confirm the user's connection. Users must respond with a Pong frame containing the same payload as the received Ping. Failure to respond within 10 minutes results in the connection being terminated.
While users may send unsolicited Pong frames, these do not prevent disconnection. If sending such frames is necessary, Binance recommends using an empty payload for efficiency.
Connection Limits
There is a limit of 300 connection attempts per five-minute period per IP address for both Websocket tools.
For WebSocket streams, users are limited to five incoming messages per second, including Ping frames, Pong frames, and JSON-controlled messages such as subscribe/unsubscribe commands. Connections exceeding this limit are disconnected, and repeated violations may result in an IP ban.
A single connection can handle a maximum of 1,024 streams, making it suitable for large-scale data monitoring setups in high-frequency trading or analytics platforms.
Rate Limits for Binance WebSocket API
Rate limits are applied to the WebSocket API, similar to REST APIs, and are measured over predefined intervals. If users exceed the shorter interval limits, they must wait for that interval to reset, even if longer intervals allow additional requests.
Violations of rate limits result in requests failing with status code 429. Users can retrieve rate limit details in two ways:
Calling the exchangeInfo stream, which provides comprehensive information on symbols and rate limits.
Making a WebSocket API request. The response includes the rate limit status unless disabled by adding "returnRateLimits":false to the payload or connection URL.
Understanding IP Limits in Binance WebSocket API
Each WebSocket API request has a weight associated with it. Heavier requests, such as those involving multiple symbols, consume more weight. The current weight usage is indicated by the REQUEST_WEIGHT rate limit type, which can be tracked using the exchangeInfo request.
Weight limits are enforced per IP address, shared across all connections from that IP. Exceeding these limits results in status 429, with the response including a retryAfter field indicating when the user can retry. Repeated violations may lead to an IP ban (status 418), which scales in duration from two minutes to three days.
Binance WebSocket Errors and Solutions
Common errors
Connection Closed: This indicates that the WebSocket connection has been terminated. Users should implement automatic reconnection logic to handle such events seamlessly.
Connection Timed Out: Timeouts may occur due to API rate limit violations or network connectivity issues. Users should verify their internet connection, ensure they are within the allowed rate limits, and retry after a brief wait.
WebSocket Server Closed (Error 1000): Disconnections with close code 1000 can result from server-side actions, network instability, or idle timeouts. Incorporating a heartbeat mechanism and robust reconnection strategies improves resilience.
Too Many Requests (Error 1008): When Binance's Spot server becomes overloaded, users may encounter close code 1008. Retrying after a delay and implementing a backoff strategy can mitigate this issue.
SSL: CERTIFICATE_VERIFY_FAILED: This error typically arises from outdated SSL certificates or incorrect configurations. Ensuring that certificates are updated and properly configured can prevent this issue.
WebSocket Stream errors
Errors specific to WebSocket streams often stem from invalid requests or parameter mismatches. These can be categorized into four types:
Unknown Property: This error occurs when invalid parameters are sent to SET_PROPERTY or GET_PROPERTY streams.
Invalid Value Type: Generated when a non-boolean value is sent for a parameter expecting true or false.
Invalid Requests: These errors may involve incorrect or excessive parameters in the request. Users should validate all inputs carefully.
Invalid JSON Syntax: Malformed JSON requests result in syntax errors. Users should test and validate JSON structures before sending them.
Best Practices
To optimize the usage of Binance WebSockets and ensure stable connections, users should consider the following best practices:
Server Load Distribution: If operating at scale, consider distributing WebSocket connections across multiple servers to prevent overloading a single server.
Connection Pooling: Use connection pooling to optimize resource utilization for high-frequency operations.
Proper Data and JSON Parsing: Always validate JSON payloads before sending them to ensure compliance with Binance's API structure. Test requests thoroughly in a development environment.
Rate Limit Backoff Mechanism: Implement a rate limit handling strategy that includes exponential backoff to manage retries after encountering rate limit errors.
Resource Optimization: Consolidate WebSocket connections where possible to reduce resource consumption. Use a single connection to manage multiple streams effectively.
Heartbeat Mechanism: Send periodic Ping/Pong messages as per Binance’s guidelines to maintain connection stability.
Load Testing: Conduct load testing on the testnet before deploying to production to ensure the setup can handle expected traffic and scenarios.
Error Logging and Alerts: Log all WebSocket errors and set up alerts for critical errors to enable prompt action.
Monitor Usage: Use endpoints like exchangeInfo to monitor your rate and weight limits in real time, avoiding violations and disconnections.
Closing Thoughts
Understanding the limitations and common errors of Binance WebSockets is essential for maintaining stable and efficient connections. By adhering to Binance's usage guidelines and implementing robust error-handling mechanisms, users can maximize the benefits of real-time, bidirectional communication.
Further Reading
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