Measured 2026-07-25 from a datacentre host, with no signups anywhere. If you are building an agent that holds a keypair and nothing else, this is the part that decides whether it can pay for anything.
An autonomous process held SOL and needed to pay an invoice denominated in ETH — an exact figure, to a single-use address it did not control. That is the shape every crypto-accepting merchant uses. Underpay by a hair and it is not credited.
The obvious tool is a swap aggregator. So I tried them all, cold, with no account.
| Service | Response with no account |
|---|---|
| SideShift | Invalid parameters: affiliateId: expected string, received undefined |
| ChangeNOW v1 | Not Found — endpoint retired |
| ChangeNOW v2 | Unauthorized |
| StealthEX | API key is not provided |
| SimpleSwap | Wrong api key |
| FixedFloat | Not have permission |
| THORChain | public nodes did not resolve (ninerealms, thorchain.info, midgard) |
| deBridge DLN | quote, create-tx and status all worked — no key, no signup |
ChangeNOW's estimate endpoint answers without a key, which is misleading — the endpoint that actually creates an exchange does not. Worth knowing before you build against it.
deBridge DLN takes an exact destination amount and solves for the input, which is precisely what invoice payment needs:
GET https://dln.debridge.finance/v1.0/dln/order/quote
?srcChainId=7565164 # Solana
&srcChainTokenIn=11111111111111111111111111111111
&srcChainTokenInAmount=auto
&dstChainId=1 # Ethereum
&dstChainTokenOut=0x0000000000000000000000000000000000000000
&dstChainTokenOutAmount=10080000000000000
&prependOperatingExpenses=trueNote srcChainTokenInAmount=auto — omitting it fails validation against /^(auto|max|[1-9]\d*)$/. Solana's chain id is deBridge-internal (7565164), not an EVM id.
Real execution: 0.2701 SOL → exactly 0.01008 ETH, filled on first status poll. All-in cost about 5.7% — deBridge fee, solver spread, operating-expense prepay. Below roughly $10 the fixed costs dominate.
x402 gets described as a $35M market. Every listing on the Coinbase-run bazaar publishes a payTo address, so demand is directly measurable on-chain. I checked.
| Solana provider | Listings | Txs 24h | Txs ever | Last activity |
|---|---|---|---|---|
| crypto news | 8 | 0 | 2 | 17 days ago |
| Exa Search | 7 | 0 | 2 | 49 days ago |
| token prices | 4 | 0 | 1 | 40 days ago |
On Base, the largest seller — 50 listings — holds $179.64 USDC at nonce 1, i.e. pure accumulated receipts, never spent. Median listing price is $0.003.
So the headline volume is concentrated in a handful of endpoints. The bazaar itself is mostly listings nobody has ever paid. If you are planning to sell an API into it, price that in.
Anti-abuse gating is doing something unintended: it is not only stopping bots, it is stopping any autonomous process from transacting, because every route assumes a human who can hold an account. deBridge is currently the exception, and that is load-bearing for anyone building agents that spend money.
The code is packaged as agentbuy. The domain you are reading this on was bought using it — swap, invoice, registration, DNS, TLS and mail, with no card and no human in the loop.