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Solana

Solana is the fastest + cheapest chain for tools402. Sub-second finality, fees around $0.00025. The wire scheme differs from Base / Polygon because Solana has no EIP-3009 equivalent — instead the buyer partial-signs an SPL token transfer and a facilitator broadcasts it.

#Identity

| Field | Value | |------------------|----------------------------------------------------| | CAIP-2 networkId | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | | Cluster | mainnet-beta | | RPC (public) | https://api.mainnet-beta.solana.com | | Explorer | solscan.io |

#USDC

| Attribute | Value | |------------------|--------------------------------------------------------| | Mint address | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v | | Decimals | 6 | | Issuer | Circle (native SPL token) | | Verified | 2026-05-17 | | Explorer link | solscan.io/token/EPjFW...Dt1v |

#Buyer payment scheme : spl-transfer

Solana uses a different scheme name than EVM chains : spl-transfer. The flow :

  1. Buyer asks the endpoint, receives a 402 with an accepts[] array. Among the entries there's one with scheme: "spl-transfer" and network: "solana".
  2. Buyer constructs an SPL token transfer instruction, signs the message partially (Ed25519 over the serialised message), and sends the { signature, from, to, amount, mint } payload in the X-Payment header.
  3. The marketplace forwards the partial-signed payload to the next Solana facilitator in priority order. The facilitator pays the network fee (~$0.00025), broadcasts the tx, returns the confirmed signature.
  4. Marketplace validates the tx on-chain and resolves the endpoint call.
text
402 quote (relevant fields)
{
  "scheme": "spl-transfer",
  "network": "solana",
  "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  "payTo": "Gt9EC4XYqD9pUmTFAfBy9b3gbGG8eiv3ZNLMLCuyU8w8",
  "maxAmountRequired": "10000",
  "maxTimeoutSeconds": 60,
  "extra": { "feePayer": "facilitator", "gasPolicy": "facilitator-pays" }
}

#Facilitator stack (3 levels)

| Priority | Facilitator | Type | Notes | |----------|---------------------|----------------------------|------------------------------------------------------------------| | 1 | PayAI Solana | External, multi-chain x402 | https://facilitator.payai.network, supports solana:5eykt4Us… | | 2 | Kobaru | External, multi-chain | https://gateway.kobaru.io (verified via docs.kobaru.io) | | 3 | local-key-solana | Same-chain self-signed | Server signs + broadcasts using TOOLS402_FACILITATOR_KEY_SOLANA (Solana keypair, base58 secretKey 64 B = seed ∥ pubkey). |

The fallback local-key-solana is a distinct keypair from the EVM local-key — Solana uses Ed25519, EVM uses secp256k1, so the keys cannot be shared.

#Marketplace recipient

text
Gt9EC4XYqD9pUmTFAfBy9b3gbGG8eiv3ZNLMLCuyU8w8

Self-custody from day one. This is a Solana keypair separate from the EVM recipient (0xD6E8…2878). Daily settlement at 00:00 UTC forwards (net of take rate) to the seller's declared Solana wallet.

#Why Solana ?

  • Fastest finality of the three chains : sub-second versus 1–2 s on Base/Polygon
  • Lowest fee of the three : ~$0.00025 per tx versus ~$0.005 on Base, ~$0.001 on Polygon
  • Best fit for high-frequency, low-value agent workflows (think : RAG retrieval at $0.0001/call, or memory ops at $0.003/op)

If your agent already lives on Solana (Phantom, Solflare, Helius RPC), this is the obvious chain. If you're starting from scratch and your stack is EVM, Base is a softer landing.