Buying Credits
Supported chains & tokens
Reference table of every network, stablecoin, and settlement method Linkex accepts.
All crypto funding (console wallet dialog and autonomous x402) settles through these assets. Amounts are always 1:1 with USD.
Mainnet assets
| Network | CAIP-2 id | Token | Settlement method | Decimals | Contract / mint |
|---|---|---|---|---|---|
| Base | eip155:8453 | USDC | EIP-3009 (gasless) | 6 | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| BNB Smart Chain | eip155:56 | $U (United Stables) | EIP-3009 (gasless) | 18 | 0xce24439f2d9c6a2289f741120fe202248b666666 |
| BNB Smart Chain | eip155:56 | USDT | Permit2 | 18 | 0x55d398326f99059fF775485246999027B3197955 |
| BNB Smart Chain | eip155:56 | USDC | Permit2 | 18 | 0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d |
| Solana | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | USDC | SVM transfer | 6 | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v |
The live list (including the recipient address per network) is served by GET /api/user/topup/x402/config — always prefer it over this table in code.
Settlement methods explained
- EIP-3009 (
transferWithAuthorization) — you sign a typed-data authorization; the facilitator submits it on-chain and pays the gas. Zero transactions from your wallet. - Permit2 — used for BNB Chain USDT/USDC, which lack EIP-3009. Your first payment per token includes a one-time
approveto the Permit2 contract (gas required once); afterwards every payment is signature-only. - SVM transfer — a Solana USDC transfer carrying the order's invoice memo; the fee payer is sponsored by the facilitator.
Settlement infrastructure
Payments are verified and settled by x402 facilitators:
| Network | Facilitator |
|---|---|
| BNB Smart Chain | Binance B402 |
| Base | Coinbase CDP (PayAI fallback) |
| Solana | Coinbase CDP (PayAI fallback) |
This is internal detail — as a payer you only ever talk to the Linkex order and pay endpoints.