Old Vs New Concept

The major drawback in my current module is that all the processing is done from Magento's side. Having this server somewhere and Checkout server in your store will cause major delays. Connections are done from Magento to Checkout's database, processes take place and the final instruction is done.

My thought is to have an API layer on Checkout's server and let it handle all DB connections and give results to Magento.

Since I am aware of Magento's APIs and framework construction, I think I will make the new module actually 2 extensions.

1- Dummy Magento Installation and have a (server-side) extension to handle Checkout DB connection and provide secure API externally.

2- The real Magento Installation to have (worldwide-side) extension.

I think this construction will save me lots of time, coz I will eventually have to kind of (split) the current extension to have a server side, and a worldwide side. So alot of work is already done.

Previously I had in plan to rewrite the Tax sync codes for proper syncing during initial setup, but never had the time to do that. I think this is the main reason people do not succeed getting my extension to work.

Where am I - Roadmap

One thing I want to clear:
All my work is goin in the way of "syncing Magento TO Checkout App"...meaning my codes will not be as useful for those who already work on Checkout as for those who work on Magento and just want to add POS like me.

Concept is, sync tax, customers, products, stock and orders.
syncing orders will run the customers sync codes along the process to successfully assign the customer to the synced product with updated shipping addresses.
I already implemented the tax sync, but for me, in Egypt, we have only sales tax of 10%, no tax regions or any other special or compound rates...So I only implemented syncing the tax rate as a tax group in Checkout.

I am currently in the middle of coding the simple products sync.
The plan is to successfully implement :
-Customers sync/detect changes and update (done)
-Tax rates sync (done)
-Sync orders (partially done-without products or amounts)
-Sku, name, prices, cost, tax assigned for simple products(in progress)
-Sync stock to update inventory total costs and ledger
-Use of variations to sync configurable products and their associated simple products
-Sync stock back to Magento
-Automate these actions somehow, like with cron jobs or trigger after event
-Create a kind of log of each process/sync done for revising and error handling/fixing situations

I really am not finding hard time coding, and I really encourage people to start working with me on this module because in 10 days I am 30% done of what I need, so this is promising.
I also want to clear out that since I'm not just developing this for the community but first of all solve my work case. Then, not all features can be implemented in this module by me since I don't have the time, and I don't have the case to work on.

Maybe we can move this project on to bazaar or other similar project management solutions