Take the community feedback survey now.

Sarah Ager
Jun 11, 2025
  765
(0 votes)

JavaScript SDK v6: Lightest, Most Efficient SDK Yet

Need a faster site and less frontend bloat? JavaScript SDK v6 is here —and it’s the lightest, smartest SDK we’ve ever released for Optimizely Feature Experimentation. 

🚀 What’s New in v6? 

  • Smaller Bundle Size: v6 slashes the bundle size down to as little as 22KB (gzipped) when configured for your needs. This means faster load times and a smoother experience for your users. 

  • Smarter Resource Management: No more manual deactivation in server-side rendering (SSR) environments. JavaScript SDK v6 manages resources more efficiently, simplifying your workflow. 

  • Advanced Decisioning Logic: Get ready for upcoming features like Contextual Bandits, async decision methods, and expanded compatibility with external datastores for sticky bucketing. 

⚠️ Before You Upgrade 

This is a major version update (v5 → v6) and includes breaking changes. 

If you rely on auto-importing the latest SDK version, now’s the time to double-check. You'll likely need to update your imports and integration logic to make the most of the improvements. 

Tip: Always pin SDK versions explicitly to avoid surprises when major updates roll out. 

🧠 Best Practices and Recommendations 

  • Avoid blindly importing packages using @latest. 

  • Review your dependencies regularly—especially SDKs that affect critical experiences. 

  • Check your SSR logic if migrating from v5—v6 simplifies it, but old patterns may conflict. 

Upgrade Today! 

Ready to experience the benefits of JavaScript SDK v6? Upgrade now and enjoy a lighter, faster, and more efficient SDK for Optimizely Feature Experimentation. 

👉 Check out the JavaScript SDK upgrade guide for everything you need to make the switch. 

📚 Need Help? 

Our support docs walk you through the upgrade, step by step. Still stuck? Reach out to support or your account team. And don't forgeting to join the community Slack. 

Jun 11, 2025

Comments

Please login to comment.
Latest blogs
Optimizely CMS Mixed Auth - Okta + ASP.NET Identity

Configuring mixed authentication and authorization in Optimizely CMS using Okta and ASP.NET Identity.

Damian Smutek | Oct 27, 2025 |

Optimizely: Multi-Step Form Creation Through Submission

I have been exploring Optimizely Forms recently and created a multi-step Customer Support Request Form with File Upload Functionality.  Let’s get...

Madhu | Oct 25, 2025 |

How to Add Multiple Authentication Providers to an Optimizely CMS 12 Site (Entra ID, Google, Facebook, and Local Identity)

Modern websites often need to let users sign in with their corporate account (Entra ID), their social identity (Google, Facebook), or a simple...

Francisco Quintanilla | Oct 22, 2025 |

Connecting the Dots Between Research and Specification to Implementation using NotebookLM

Overview As part of my day to day role as a solution architect I overlap with many clients, partners, solutions and technologies. I am often...

Scott Reed | Oct 22, 2025