Skip to main content

Avoid round trips to internal servers

note

Don't be blocked! We're here to help you get up and running with Eppo. Contact us at support@geteppo.com.

Centralizing experiment assignment on an internal server can lead to performance issues and poor user experience. Eppo's client-side SDKs work best when they can evaluate assignments locally without additional network calls.

What Happens With Internal Server Round Trips​

When implementing centralized experiment assignment on internal servers, you'll face two main challenges:

  1. Performance Impact:

    • Each call to the server adds latency for each flag evaluation
    • Additional server load and maintenance
    • More complex application architecture

  2. Implementation Compromises:

    • Pressure to implement "fetch all flags at initialization"
    • Potential conflicts with other best practices
    • Reduced quality of analytic data

Best Practice​

Use Eppo's client-side SDKs for most use cases. They:

  • Pre-fetch obfuscated flag configurations
  • Perform assignment logic locally
  • Evaluate flags only when features are rendered
  • Typically complete round trips in under 20ms

Exception Cases​

Server-side assignment can be useful in the following cases:

  • Experiences originate from the backend
  • A/B testing machine learning models with server-side predictions
  • Other scenarios requiring server-side logic
tip

If you need to remove the CDN dependency entirely, you can fetch Eppo's configuration file independently and pass it to the client during app initialization. See our deployment modes documentation for details.