Post by xinaida about PayAI ($PAYAI)

I ran $PAYAI official Python x402 quickstart (x402[svm] 2.24.0, httpx client) against their own live Echo Merchant demo, Solana devnet endpoint (https://x402.payai.network/api/solana-devnet/paid-content), exactly as documented.

The docs advertise this demo as letting you "test on the networks supported by x402 without juggling faucets or balances." In practice: the 402 response requires USDC devnet (mint 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU, only found by decoding the raw JSON — no faucet link anywhere in the docs). After funding my wallet with 20 USDC devnet + 10 SOL (confirmed on-chain) and retrying, the request still fails: "error":"invalid_exact_svm_transaction_simulation_failed".

I traced this in the SDK source (x402/mechanisms/svm/exact/client.py): the client builds a TransferChecked instruction into the payTo address's Associated Token Account for the USDC-devnet mint. Checking that address on Solana Explorer (devnet) — 8sqyMHQwBh8BCXC99pdgt6BpXwLu9xqfL1hDV5SFYf3R — shows zero token holdings. The merchant's own devnet receiving account for USDC was never initialized, so the transfer instruction targets a token account that doesn't exist. This means the Solana devnet endpoint of the Echo Merchant is currently broken for every user, not just misconfigured on my end — reproducible on two separate networks, with confirmed wallet balances both times.

Questions for the team:

Can the Echo Merchant's payTo ATA for USDC-devnet be initialized (or auto-created server-side before simulation)?

Is Solana mainnet or another network's endpoint affected by the same class of issue?

Suggestion: surface a clearer error than the generic invalid_exact_svm_transaction_simulation_failed when the destination account doesn't exist — it currently looks like a client-side balance problem when it's actually server-side.