OpenSettle abstracts six chains behind one API. Pick a chain per payment or per merchant; the same Router contract semantics apply everywhere. These numbers are observed medians from production traffic over the last 30 days.
| Chain | Tokens | Settlement | Gas | Autopay |
|---|---|---|---|---|
Base base-mainnet | USDC, USDT | 2–4s | $0.001–0.01 | All modes |
Arbitrum arbitrum-one | USDC, USDT | 1–3s | $0.005–0.05 | All modes |
Polygon polygon-pos | USDC, USDT | 3–6s | $0.002–0.02 | All modes |
Tron tron-mainnet | USDT | 3–5s | ~$1.20 (energy) | Allowance, Invoice |
Ethereum eth-mainnet | USDC, USDT | 12–30s | $2–25 | All modes |
Solana solana-mainnet | USDC, USDT | <1s | <$0.001 | Invoice only |
Default recommendation for new EVM integrations. Cheapest finality with native USDC issued by Circle.
Lowest median latency. Slightly higher gas than Base under load. Native USDC since 2023.
Use the native USDC contract (0x3c49…3359), not the bridged USDC.e. We auto-route to native.
TRC-20 is ERC-20 compatible at the ABI level — same allowance flow. USDT only; USDC is not deployed at meaningful liquidity.
Highest fees and longest finality. Reserve for large invoices (>$5,000) where gas is rounding error.
One-time payments and invoice subscriptions only — Solana has no ERC-20 allowance equivalent. Smart-wallet autopay coming Q3 2026.
We monitor block production, RPC health, and median fee on every chain. When a chain's health score drops below our threshold, new checkouts on that chain show a banner suggesting an alternate route, and the API returns a chain_degraded warning header on responses (not an error). Subscriptions on degraded chains queue renewals and retry once health recovers; you will see a subscription.renewal_deferred webhook with the next attempt time. We never auto-switch chains for an active subscription — the customer's allowance lives on a specific chain, and silently moving funds would violate the consent they gave.
For one-time checkouts, you can opt into auto-fallback by passing settlement.fallback_chains on creation. We will rewrite the checkout to a healthy chain at page load if the primary is degraded.