Been meaning to post this here instead of just reddit. Earlier this year I got into x402 after seeing it around, messed with it for a bit. It's just a set of HTTP headers, chain agnostic on paper, but every facilitator that actually exists is pretty much just USDC on EVM or Solana. Nothing for XMR, and I don't think any "official" implementation is going to bother prioritizing it.
The other issue is how most people would even wire XMR into it, which is giving your view key to whatever service is doing the verifying for you. Didn't like that either.
So I built a facilitator sidecar in Rust that does the Monero stuff, subaddress per invoice, USD to piconero conversion with Kraken/CryptoCompare failover, and the verify/settle endpoints x402 expects. It talks to your own monero-wallet-rpc so the view key never leaves your box. Confirmations required is configurable (I've only actually tested 0-conf tho so I'm not fully sure how higher conf levels will behave.) Repo's here if anyone wants to look: https://github.com/x402-Systems/xmr-x402-facilitator
Reason I even got into x402 in the first place, I wanted something real to test it against, and figured an API-driven reseller like sporestack would be a decent fit for that kind of use case, so I set one up on Hetzner boxes as an experiment. Never really got users, and looking back the pricing I set were insane
The thing I actually want opinions on: x402 pushes really hard on the agent to agent angle, AI agents with their own wallets paying for stuff autonomously. I don't fully buy that as a real use case yet vs a narrative. But the base idea, pay per request over HTTP, seems kinda useful regardless of who's on the paying end. Does XMR actually have a shot at getting adopted into that kind of infra, or is it always going to be one off sidecars like this? And more broadly, does x402 itself seem like something people here would actually have use for or see value in, separate from whether XMR ever gets proper support in it?