The Django engine would be the simplest to use with App Engine by far given that it's native. If you're interested in baby steps I would (and did) start with D

The Django engine would be the simplest to use with App Engine by far given that it's native. If you're interested in baby steps I would (and did) start with Django and migrate to Jinja2 (it's a simple migration, Jinja2 is almost syntactically identical to the Django engine). In my experience Django takes no effort to make immediate use of but has several weird quirks that drove me away from it into the loving arms of Jinja2. On the other hand Jinja2 takes a little more effort to setup (and is slower, unless you pre-compile and cache your templates which is an extra step to worry about).