In Contentful, the easiest way to change your content model is through the web app on app.contentful.com. This is pretty straightforward if you are doing basic changes like adding a new text field. However, if you are planning more complex changes, migration scripts are probably the best way forward. By using migration scripts, you can add and delete fields like you can in the web app, and you can also create and insert content into existing entries.
In Optimizely's cloud hosting service DXP, Optimizely has for a long time offered to generate certificates for the sites it hosts, giving us the secure https URLs with a reassuring padlock next to it.