The first thing that I would do is to research both mobile-frameworks and generate-your-own- mobile-app- without-writing- code sites ... which do exist already.   Find out which APIs they use and plan from the start that your site must expose, and should therefore also itself use(!), that API.

Your project, therefore, is going to initially consist of two loosely-coupled programs.   The first is the API-driven core.   The second is a web-page front end, which also supports browser-detection.   Use an existing framework of some kind to build this part.   In the future, the mobile apps will constitute another front-end.

The fly in this ointment is that you basically have to design all three parts now ... the core, the web front-end, and the mobile app or apps.   Furthermore, since you can correctly guess that you really can’t afford to plan to write for iOS + Android + who-knows-maybe Windows, you have to find a way to auto-generate that part.   And you’d really like to find a way to auto-generate all of the front-end parts, all at the same time ... which, in fact, you now can.

Absolutely anything-and-everything that can be commoditized, is being commoditized.   No one can completely commoditize whatever-it-is that the back-end “guts” of your server is doing, of course, but there are dramatic reductions in the costs associated of doing the stuff that front-faces the user.   Since this is a green-field situation, you absolutely must make the most far-reaching decisions now.   Start with pure-research, and set aside the notion that Perl is going to be front-and-center of what you do.   It will, and still should, be the primary host-side tool.   But it might not be the tool that is “driving the bus” of this project as-a-whole.   Your traditional ways of thinking need to be upturned with this new apple-cart, without losing your senses or jumping off the cliff because you haven’t spotted where the bridge just moved-to.   To me, it’s kinda like those ads that Karras Negotiating has been running lately in all those in-flight mags:   Re-examine .. everything.

I’m very much in the process of helping several clients do that right now, and it’s one heck of a ... o_O ... ride.   “omg, the world is totally-changing all over again.”   What a crazy way we all picked to make a livin’.   I guess we’ve all got a choice between being terrified and being excited.   I pick door number two.