Stable Genius

• Name: Stable Genius
• URL: https://www.stablegenius.co/
• Category: stablecoin payments infrastructure / POS-and-checkout control plane / non-custodial merchant settlement stack
• Tags: ethereum-ecosystem
• Summary: Stable Genius is merchant settlement plumbing. The useful part is the operator layer around USDC acceptance: merchant onboarding, proxy-contract deployment, payment-intent APIs, settlement scheduling, and signed webhooks. It is not a new payment rail.
• What it does:
  • Lets merchants accept USDC payments through POS terminals, apps, or online checkout flows while settling proceeds to USD bank deposits
  • Returns payment addresses and EIP-681 QR payloads via API so integrators can render wallet-ready payment requests without handling wallet logic themselves
  • Onboards merchants through dashboard-based account creation, KYC/KYB, bank-account linking, and deployment of a non-custodial on-chain proxy contract
  • Exposes REST API endpoints for creating and tracking payment intents, retrieving merchant data and balances, and listing transactions
  • Supports multi-merchant platform integrations where one integrator can process payments for several merchants through a shared API surface
  • Delivers webhook events for payment confirmation and settlement lifecycle updates, with HMAC-SHA256 signature verification and replay-protection guidance
  • Automates USDC-to-USD conversion and ACH payout through a linked banking partner while preserving emergency withdrawal paths from the merchant’s on-chain contract
• Key claims:
  • The docs homepage says Stable Genius enables stablecoin payments with “one API call to create a payment” and “one webhook when it’s confirmed,” while the merchant gets USD in their bank account
  • The official site says funds go directly to a wallet only the merchant can access and that Stable Genius never holds, touches, or transfers the merchant’s money
  • The supported-assets docs surface in the docs index plus the homepage indicate Base + USDC are live first, with Solana, Arbitrum, Optimism, Ethereum, and USDT listed as coming-soon or planned expansions
  • The merchant docs say onboarding includes KYC/KYB, Plaid or manual bank linking, and deployment of an on-chain proxy contract that becomes the merchant payment address
  • The how-it-works guide says payment intents return an EIP-681 QR payload, transaction confirmation triggers a payment_intent.confirmed webhook, and settlement to bank accounts occurs through automatic or manual withdrawal schedules
  • The settlement docs say the default schedule is weekly Monday 8am EST, manual cash-out is also available, and ACH settlement usually lands 1–3 business days after withdrawal initiation
  • The merchant docs say the default fee rate is 1% and that fee splitting happens on-chain through the merchant proxy contract, making both fees and net proceeds independently verifiable
  • The webhook-security docs specify X-StableGenius-Signature and X-StableGenius-Timestamp headers, HMAC-SHA256 verification, constant-time comparison, and a 5-minute freshness window for replay protection
  • The API overview describes a private-beta REST API at https://api.stablegenius.co/v1 with bearer-token auth, cursor pagination, version pinning, and rate limits for sandbox and production keys
• Whitepaper: No canonical standalone Stable Genius whitepaper or litepaper surfaced in this pass. The clearest current sources of truth are the official site and docs corpus; see ../whitepapers/stable-genius-primary-sources-2026-05-02.md.
• Sources:
  • https://www.stablegenius.co/
  • https://docs.stablegenius.co/
  • https://docs.stablegenius.co/llms.txt
  • https://docs.stablegenius.co/how-it-works
  • https://docs.stablegenius.co/api-reference/overview
  • https://docs.stablegenius.co/concepts/merchants
  • https://docs.stablegenius.co/concepts/settlement
  • https://docs.stablegenius.co/api-reference/webhook-security

Internal linkages

• Best upward reads: bridge-xyz, coinflow, and openpayd.

Control surface

• Authority sits in merchant onboarding, proxy-contract deployment, bank-link approval, fee-split configuration, settlement cadence, and webhook reliability.

• The non-custodial proxy helps keep merchant funds visible. It does not remove the operator layer around conversion, payout, and merchant admission.

• Read Stable Genius as a hosted merchant-settlement stack on Ethereum rails, not as a stablecoin payments anchor.

• Last reviewed: 2026-06-01 UTC