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Realtime Updates

Overview​

This article serves to explain how the SDKs handle realtime updates triggered by changes to your features from the DevCycle dashboard.

DevCycle leverages Server-Sent Events (SSE) to notify the SDKs that their config has changed and that they should fetch a new config. When a change to a feature (targeting rules, variable values, etc.) has been saved, our servers send an SSE to anyone subscribed to that project and trigger the SDK to request a new config from DevCycle.

Client-Side SDK​

A connection URL is included in the config that the SDK fetches, triggering the SDK to open a connection with our SSE provider listening for any changes from the dashboard.

The following Client-Side SDKs currently have Realtime Updates:

  • Javascript SDK
  • React SDK
  • iOS SDK
  • Android SDK
  • React Native SDK
  • Flutter SDK

Javascript SDK, React SDK​

If the user loses focus on the webpage for longer then the inactivityDelay (the default of which is set to 2 minutes, and can be configured through the options), the SDK will disconnect from the SSE provider and will reconnect when the user opens the tab / window again (i.e. the page's visibility state = visible). The SDK will also request a new configuration during reconnection to receive any updates it may have missed while the realtime connection was closed.

iOS SDK, Android SDK & Flutter SDK​

If the user backgrounds the application for some period of time, the SDK will disconnect from the SSE provider and will reconnect again when the user brings the application to the foreground. When the application is brought to the foreground the SDK will request a new configuration to receive any updates it may have missed while the realtime connection was closed.