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Meridian x402

developer

Meridian documents x402 facilitator support for Robinhood Chain with USDG — setup, env, honest status, and what HISS does and does not claim.

Meridian is a third-party x402 payment facilitator built on proxy-facilitator architecture. Its supported-networks table documents the robinhood network — which makes Meridian the payment lane HISS uses for Robinhood Chain x402 settlement when configured and verified.

Verified network row (2026-07-08)

From docs.mrdn.finance/api-reference/supported-networks, verbatim:

  • Network: robinhood
  • Chain ID: 4663
  • Payment token: 0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168 — the canonical Robinhood Chain USDG address (6 decimals)
  • Facilitator: 0x8E7769D440b3460b92159Dd9C6D17302b036e2d6 (X402ProxyFacilitator V6, identical across all sixteen Meridian mainnet networks)
  • Cross-chain: Across

Mainnet-only. The table has no Robinhood Chain testnet (46630) row, so the Meridian lane exists only for chain 4663.

How the seller flow works

  1. The HISS server rebuilds payment requirements for the named service on every request — buyer-supplied amount, network, token, and recipient are never trusted.
  2. The service answers with a 402 challenge carrying those requirements.
  3. The buyer signs an EIP-3009 TransferWithAuthorization from their own wallet (viem; no SDK exists — Meridian's demo helpers are meant to be copied).
  4. The server settles via POST https://api.mrdn.finance/v1/settle using the server-only key, then records a deterministic payment receipt to Postgres.

POST /v1/settle is the primary endpoint; /v1/verify is deprecated (legacy integrations only) and HISS does not build on it.

Environment

bash
# Server-only Bearer key (pk_test_ dev / pk_ live). Never NEXT_PUBLIC_.
MERIDIAN_API_KEY=
MERIDIAN_ENABLED=false
MERIDIAN_FACILITATOR_URL=https://api.mrdn.finance/v1
MERIDIAN_NETWORK=robinhood
MERIDIAN_CHAIN_ID=4663
MERIDIAN_USDG_ADDRESS=0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168
MERIDIAN_FACILITATOR_ADDRESS=0x8E7769D440b3460b92159Dd9C6D17302b036e2d6
MERIDIAN_PAYTO_ADDRESS=

The recipient wallet is bound to the API key's organization on Meridian's side; HISS additionally pins payTo server-side and fails closed on any mismatch. Meridian's demo repo is Base-Sepolia-oriented — its network configuration is never copied into production.

Status and routes

  • GET /api/x402/meridian/status — configuration booleans, docs-derived constants, and a live /v1/supported reachability check when a key is present. No secrets, ever.
  • POST /api/vaults/x402/[serviceName]/requirements — server-built payment requirements for a vault service on the selected lane.
  • POST /api/x402/meridian/settle — server-side settlement; returns 503 MERIDIAN_NOT_CONFIGURED honestly until env is set.

$HISS is independent research software in pre-execution readiness checks — not investment advice, and not affiliated with Robinhood, Bankr, or Chainlink.