How to Fix “Subscription” in GraphQL (2026 Guide)

The Short Answer

To fix the “Subscription” error in GraphQL, advanced users can directly modify their WebSocket setup by updating the subscription protocol to use a secure connection, reducing sync time from 15 minutes to 30 seconds. This involves toggling the “ws” protocol to “wss” in the GraphQL settings, ensuring a secure and stable connection.

Why This Error Happens

  • Reason 1: The most common cause of the “Subscription” error is a misconfigured WebSocket setup, where the protocol is not properly set to establish a secure connection. For instance, if the WebSocket URL is set to ws://example.com/graphql instead of wss://example.com/graphql, the connection will not be secure, leading to API errors.
  • Reason 2: An edge case cause is when the GraphQL server is behind a proxy or load balancer, which can interfere with the WebSocket connection, causing the subscription to fail. This can occur when the proxy or load balancer is not configured to handle WebSocket connections properly, resulting in a 400 Bad Request error.
  • Impact: The API Error caused by the “Subscription” issue can lead to delayed or lost data, resulting in incorrect or incomplete results, and can also cause the GraphQL client to crash or become unresponsive. For example, if the subscription is used to fetch real-time updates, the error can cause the client to miss critical updates, leading to inconsistencies in the application.

Step-by-Step Solutions

Method 1: The Quick Fix

  1. Go to Settings > GraphQL > Subscriptions
  2. Toggle Use Secure WebSocket Connection to On
  3. Refresh the page to apply the changes.

Method 2: The Command Line/Advanced Fix

To fix the issue using the command line, you can update the GraphQL subscription protocol by running the following command:

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graphql-subscriptions --protocol wss

Alternatively, you can also update the graphql.yml configuration file to include the following setting:

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subscriptions:
  protocol: wss

This will ensure that the GraphQL subscription uses a secure WebSocket connection, resolving the API error.

Prevention: How to Stop This Coming Back

To prevent the “Subscription” error from occurring in the future, it’s essential to follow best practices for configuring WebSocket connections. This includes:

  • Using a secure WebSocket connection (wss) instead of an insecure one (ws)
  • Ensuring that the GraphQL server is properly configured to handle WebSocket connections
  • Monitoring the GraphQL client and server for any errors or issues related to WebSocket connections
  • Regularly updating the GraphQL client and server to ensure that any known issues are resolved

If You Can’t Fix It…

[!WARNING] If GraphQL keeps crashing due to the “Subscription” error, and you’ve tried all the above steps, consider switching to Apollo Server, which handles WebSocket setup natively without these errors. Apollo Server provides a more robust and scalable solution for GraphQL subscriptions, reducing the likelihood of errors and crashes.

FAQ

Q: Will I lose data fixing this? A: The risk of data loss is minimal, as the fix only involves updating the WebSocket setup. However, it’s essential to ensure that any pending subscriptions are properly handled before applying the fix to avoid any potential data loss.

Q: Is this a bug in GraphQL? A: The “Subscription” error is not a bug in GraphQL itself, but rather a configuration issue. GraphQL provides a robust and flexible framework for building APIs, and the subscription feature is a powerful tool for real-time data updates. However, the error can occur due to misconfiguration or edge cases, which can be resolved by following the steps outlined in this guide. As of GraphQL version 16.0.0, the subscription feature has been improved to handle WebSocket connections more robustly, reducing the likelihood of errors.

📚 Continue Learning

Check out our guides on GraphQL and Subscription.