Payment infrastructure worth exploring here. The core setup relies on A2A and 402 protocol integration—402 being the foundational standard while the newer extension layer builds on this base architecture.

That's actually why I structured the Solana automation toolkit this way. Built it to sit on top of that proven 402 foundation instead of reinventing. Also took inspiration from some existing developer frameworks and cross-referenced the A2A payment model specifications.

It's interesting how these protocol layers compound. Rather than starting from scratch, you can leverage what already works and focus on optimization at the application level. The graphic above breaks down exactly how these pieces fit together in the payment flow.