> The protocol boast "no fee" but that's deceptive: if it's based upon a blockchain, there will be transaction fees.

These days many transaction types onchain are completely free and subsidized because gas costs are subcent[1].

x402 functions predominantly on L2 networks like Base, where individual tx costs between agents are generally not a factor.

[1] https://www.gasfees.io/

According to that site Base USDC fee is 1/8th of a cent. The x402 whitepaper says 1/100th of a cent so I'm not sure what accounts for the discrepancy; maybe Coinbase is willing to subsidize fees in some cases.

Gas is variable, but Coinbase currently subsidizes x402 transactions that go through our facilitator

The protocol has no fees. If you use it with a blockchain, then there might possibly be a fee. If you use it with VISA, there will be a fee, etc.

x402 as a protocol has no fees, but the underlying network transactions are conducted on my have costs. Merchants can choose the underlying network transactions are conducted on that best fit their usecase. x402 also has the concept of a facilitator, which exists to abstract away the underlying payment networks. Many facilitators (including Coinbase's) subsidize the gas used for transactions.

> if it's based upon a blockchain, there will be transaction fees

Not necessarily. Crypto wallet can authorize expense just by signing something and sending that signature. No blockchain transaction takes place. Then these signatures are batched.

Coinbase's blockchain (Base) generally has sub-cent send fees for USDC. Solana's fees are also in that ballpark.

Nano has 0 transaction fees in the sense that you have to do some work function instead to prevent spam

Obligatory self promotion https://www.youtube.com/watch?v=8hHG8gOkZBE & https://github.com/SerJaimeLannister/randomnano & just because I am lazy and I had never written what this software is except in one comment on HN which I am also going to link lol which is going to be best that I can sum it up with https://news.ycombinator.com/item?id=44700680

Which loops through a lot of transactions with a custom nano vanity id generator to embed data into blockchain which would have 0 gas fees.

Want to do something with it one day but not sure how to, or even if its worth it given the decentralized nature and Like, I want to really play with it once I can secure myself a college and then a job & maybe I will do it in my side project.

all these are solvable problems

we can get decentralized systems to sub 0.0000000000001 cent fees. Fee volatility Wille xist but thats a prerequisite for openness.