Chains
tools402 settles on three chains. All three carry native USDC issued by Circle — no bridged USDC.e — at the canonical addresses below. A seller picks one wallet per chain it wants to receive on; the buyer picks one chain it wants to pay on; if the two differ, the marketplace bridges between them via cross-chain settlement (V1, Mayan-only).
#Comparison
| Chain | CAIP-2 networkId | USDC contract / mint | Buyer scheme | Typical gas | Finality |
|---------|-----------------------------------------------|-------------------------------------------------------|---------------------|-----------------|-----------------|
| Base | eip155:8453 | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 | exact (EIP-3009) | ~$0.005 | 1 block (~1.2 s) |
| Polygon | eip155:137 | 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 | exact (EIP-3009) | ~$0.001 | ~2 s |
| Solana | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v | spl-transfer | ~$0.00025 | sub-second |
Source of truth : src/config/chains.ts on the
server. The CAIP-2 networkIds and USDC contracts are verified against Circle's
canonical issuance list (2026-05-17).
#Marketplace recipient wallets
These are the addresses the buyer's payment lands on. Settlement to the seller
happens daily at 00:00 UTC from these addresses.
| Chain | Recipient |
|---------|-------------------------------------------------|
| Base | 0xD6E8aF2F65B4C9ACC7BF14A3096056e89E312878 |
| Polygon | 0xD6E8aF2F65B4C9ACC7BF14A3096056e89E312878 |
| Solana | Gt9EC4XYqD9pUmTFAfBy9b3gbGG8eiv3ZNLMLCuyU8w8 |
Base and Polygon share the EVM address (same secp256k1 key, HD-derived). Solana is a separate Ed25519 keypair. Both are self-custody — tools402 does not hold a private key for either; payments land on the seller's own wallet on settlement day, never our books.
#Picking a chain (buyer)
There is no wrong answer — pick the chain you already have USDC on. The marketplace returns all three in the 402 quote and the buyer chooses. If the buyer pays on a chain that's not the seller's preferred settlement chain, cross-chain settlement handles the bridge (V1 via Mayan, ~30 s to ~2 min depending on direction).
- Base — default for most agent stacks (Coinbase ecosystem). Lowest finality + lowest dev friction.
- Polygon — cheapest gas. Pick this if you do many small calls and want to minimise ETH spend on gas.
- Solana — fastest finality + lowest fee. Pick this if you already have Solana USDC, or if your agent prefers sub-second confirmation.
#Picking a chain (seller)
The same wallet receives on whichever chain the buyer pays. The seller does not
have to pick — the marketplace handles routing. Multi-chain accepted_chains is
declared per endpoint in /v1/_meta (defaults to ["base", "polygon", "solana"]
on first-party endpoints, per Wave SOL.3+).
#Deep dives
- Base — EVM, EIP-3009 gasless transferWithAuthorization
- Polygon — EVM, same EIP-3009 scheme as Base
- Solana — SPL token transfer, partial-sign facilitator-broadcast
- Facilitators — 9 facilitators across the 3 chains, independent failover