Get the datafile

The datafiledatafile is a JSON representation of the current state of flag rules for an environment in your Feature Experimentation project. It contains all the data needed to deliver and track your flag deliveries and experiments. By syncing a local copy of this datafile, the SDK can run flag rules without making a blocking network request to an outside API, ensuring microsecond latency.

Sync your application with the datafile using the following methods:

When choosing how you sync the datafile, consider the tradeoffs between accuracy and latency. The more frequently your application gets the datafile, the more accurate your application is with the Optimizely Feature Experimentation project environment, but the more latency you generate through network traffic. If you want to centralize your network connections to the datafile, consider using Optimizely AgentOptimizely Agent.

The datafile updates when you save changes to your flags in the Optimizely app, and changes are typically reflected in the datafile within two seconds. The time depends on the SDK language and version, the sync method, and the local cached copy version. If you are experiencing delays longer than 15 seconds, contact Optimizely Experimentation Support.

If you prefer not to sync each of your SDK instances individually with the Optimizely CDN, you can fetch the datafile through a single instance of the SDK, then pass that to other instances. For an example use case, see Multiple SDK implementationsMultiple SDK implementations and Sharing the datafile with client SDKsSharing the datafile with client SDKs.

Fetch the datafile for an Agent microservice instance through the get datafile endpointget datafile endpoint.

For troubleshooting purposes, you can view the datafile in the Optimizely app. For secure environmentssecure environments, accessing the datafile in this manner is not supported. Instead, you can access the datafile at initialization, passing the datafile access token for authentication.

To access the datafile for your project, complete the following:

The following image shows how the datafile displays when accessed from the CDN URL. You can also use this URL to implement your own custom datafile fetching.

For a properly formatted JSON datafile, see Example datafileExample datafile.