feat(x402): first-class Solana (SVM) support — partial-signed tx, fee payer, verify/settle#30
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… payer, verify/settle Adds Solana to the existing x402 rail without a new rail type. EVM and Solana differ only in client authorization (no EIP-3009 — the client builds and partially signs a real SPL transfer, leaving the fee-payer slot for the facilitator) and a couple of requirement fields. Rail (src/rail-adapters/x402-rail.ts): - X402RailConfig.feePayer + extra.feePayer injected for Solana challenges - x402Version auto-defaults to 2 for SVM (the "exact" scheme is a v2 scheme) - discoverFeePayer(): pulls the fee payer from the facilitator's /supported Client signer (examples/x402-solana-recovery/sign-payload.mjs): - buildSolanaPaymentPayload(): ComputeBudget(limit) + ComputeBudget(price<=5) + TransferChecked + Memo(nonce), partial-signed, base64 -> x402 v2 payload - @solana/web3.js + @solana/spl-token dynamically imported (dev-only) Tests (verify and settle exercised separately, success AND failure each): - x402-solana-rail.test.mjs: challenge shape, fee-payer discovery, verify/settle success + failure paths (facilitator stubbed via fake fetch) - x402-solana-sign.test.mjs: offline signer — payload is v2, fee-payer slot empty (partial sign), tx carries the 4 expected instructions Full suite: 228 passing. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…evnet runner Ran the full rail end-to-end against PayAI + Solana devnet and corrected the client signer to match the live SVM "exact" v2 wire format. The rail's own verify/settle bodies were already correct — fixes are client-side only. Confirmed devnet settle (err: None), fee paid by the facilitator's fee payer (not the client): tx 5JeSK1je6xrt3HouPUSKheawqiwJhVPtSufqyzNgyqCLBKSZ11Krvty... Signer (examples/x402-solana-recovery/sign-payload.mjs): - PaymentPayload now embeds the agreed requirement under `accepted`, with the amount as an atomic STRING field `amount` (facilitator rejected the old shape) - compute-unit limit default 120k -> 30k (facilitators reject too-high limits; too-low fails simulation), price still clamped to <= 5 Add examples/x402-solana-recovery/devnet-settle.mjs — self-transfer devnet smoke test (discover feePayer -> challenge -> partial-sign -> /verify -> /settle), prints the explorer link. Local payer keypair path is gitignored. Tests updated for the new payload envelope. Full suite: 228 passing. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Beyond the self-transfer smoke test, ran a real payer -> recipient transfer on devnet via PAY_TO: moved exactly 0.001 USDC (payer 20 -> 19.999, recipient 20 -> 20.001), gas paid by the facilitator, err: None (tx de6S852jpFTJ1hHLNMBPAaWqrkkMXzjq8XqPbbCf3LD4s1Mm6ZDAU3ah6dxUZueyN19U...). Also documents that the SVM "exact" fixed instruction layout means the recipient's token account must exist before settle. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…m-rail # Conflicts: # .gitignore # src/rail-adapters/x402-rail.ts
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Summary
Adds Solana (SVM) support to the existing x402 rail — no new rail type. x402 is EVM-rooted (EIP-3009 + EIP-712), but the SVM "exact" scheme is fully supported by facilitators; the rail was already chain-agnostic on verify/settle, so the real work was the client authorization and a couple of requirement fields.
EVM vs Solana, what actually differs:
transferWithAuthorization, EIP-712 sig/settleChanges
Rail —
src/rail-adapters/x402-rail.tsX402RailConfig.feePayer; injected asextra.feePayerfor Solana challenges (the client needs it to leave the fee-payer slot empty)x402Versionauto-defaults to 2 for SVM networksdiscoverFeePayer()— pulls the fee payer from the facilitator'sGET /supportedand caches itClient signer —
examples/x402-solana-recovery/sign-payload.mjsbuildSolanaPaymentPayload():ComputeBudget(limit) + ComputeBudget(price ≤ 5) + TransferChecked + Memo(nonce), partial-signed, base64 → x402 v2 payload@solana/web3.js+@solana/spl-tokenare dynamically imported (dev-only) so the core SDK install stays lightDocs —
examples/x402-solana-recovery/NOTES.md(end-to-end flow, facilitator options: PayAI / Coinbase CDP / self-hosted Kora) + README status row.Tests (verify & settle separate; success AND failure each)
src/__tests__/x402-solana-rail.test.mjs— challenge shape (mint/payTo/v2/feePayer), fee-payer discovery, and verify success / verify reject / verify non-200 / settle success / settle success:false / settle network-error — facilitator stubbed via a fakefetch, no network.src/__tests__/x402-solana-sign.test.mjs— offline signer: payload is x402 v2, fee-payer signature slot is empty (partial sign), serialized tx carries the 4 expected instructions.Full suite: 228 passing, typecheck clean.
Notes / follow-ups
pay.shintentionally not integrated here; it sits on top of x402 and can be a later layer.🤖 Generated with Claude Code