I adjust the position of elements on Blocs with padding and margins and check with the “developer responsive views” in Firefox and Safari to see how things will look. The arrangement of things in the Blocsapp is normally very different from the way things look in the browser views. Can I trust the browser responsive views to be correct? It would be unfortunate to do all this work and end up with a mish-mash when I go live.

Always work testing locally from the exported project before uploading, though limited in it will not confirm tablet and phone layouts.

I didn’t think of exporting the project before checking. Thanks. I am checking the formatting often. The mobile phone view is the most important for us - and the most difficult to get right. When the views on the browser “developer responsive design modes” are good and well aligned, the Blocsapp working views are pretty whacky - they don’t correspond to the end result. It would be unfortunate to have to redo everything once I go live.

I agree, nothing worse that multiple tiny tweaks uploaded to get the final result. There has to be a desktop emulator out there.

Does this help at all:

Also found these, I have never used so no guarantees:

Now this one looks hopeful, worth checking it out:

If you have a NAS storage handy (I use time capsule) try copying exported files there and looking at it from tablet, another computer or phone.
Just a thought.

These are very welcome suggestions - and I will check out each one. Thanks to all!

Just remember, there are more devices and sizes than you can imagine. You can never check them all.

Using a browser and adjusting the browser width will give you a good indication of how the page will be displayed and is very quick to do.