Improving our diff view through customer feedback and developer research

The Fastly app’s diff view allows you to make comparisons of lines of code. It’s one of the most-used features in the Fastly UI — and since it’s so popular, it’s also one of the features that we get the most feedback on.

Based on customer feedback, requests, and testing, plus inspiration with diff experiences we enjoy using, we’ve rolled out six improvements — already live in the UI — that result in an enhanced diff view user experience. Let’s dig in on what we’ve changed. 

VCL diff and YAML diff


Previously, the diff was just for the YAML configuration. Now, you can easily view the generated VCL of the configuration as well from a dropdown.

Yaml Vcl selection

Lines of code

With the added VCL generation, it now makes sense to show line numbers (where it had not with just YAML) — to make it easier to compare and to communicate to team members where changes occurred.

Collapsing unchanged code

This was the top request we got from our customers — now the diff view collapses unchanged lines of code by default to make it easier to scan and review changes. 

Expand all/collapse all

To give you more control of how you view the diff, lines of code can now be expanded or collapsed all at once.

Expand Collapse

Swapping back and forth the versions to diff

Depending on what you’d like to diff against or between, you can select which version is the one being “compared to” with an easy toggle. 

Swap versions

Activating a version from the diff

Everything looking good based on reviewing the diff? Now you can activate right from the view. 

If you’re a Fastly customer, you’ve probably already noticed these changes in your UI. If you’re not yet a Fastly customer, sign up for a free account.

Share this post