I didn't get into Clarity in my summary above but really into the decidable smart contract language design. The reason I didn't mention Clarity is because most programs on Blockstack are not smart contracts. We think that smart contracts are only a subset of use-cases and should only be used when needed vs. making smart contracts the only way to program decentralized apps.

For any readers that are intrigued by what is Clarity, it's Blockstack's smart contract language that is different in two mains ways:

a) Clarity is a decidable language i.e., it is intentionally Turing-incomplete. This allows for complete static analysis of the entire call graph of smart contracts.

b) Clarity is interpreted. The contract source code itself is published and executed by blockchain nodes i.e., no compiler.

More details on Clarity are here: https://blog.blockstack.org/introducing-clarity-the-language...

> We think that smart contracts are only a subset of use-cases and should only be used when needed vs. making smart contracts the only way to program decentralized apps

Totally agree.

Great job with blockstack, the APIs seem real easy to use - only thing I'm worried about is that the mobile SDK's are just JS wrappers so the JS bridge might be a speed bottleneck in mobile apps. Also, are there plans for a Flutter SDK (pretty easy to make a wrapper for both platform SDK's)?

I develop a proof of concept for flutter:https://github.com/friedger/flutterblockstackplugin

Again, this is just a wrapper for blockstack.js. I think the more apps it use the better the SDKs will become.

Most apps should work as PWAs anyway, I think.

Oh the mobile SDKs need a lot of attention and love. We're putting it on our roadmap: https://blockstack.org/roadmap