Chains and tokens

OpenRampKit names chains with CAIP-2 ids and tokens with their address (or native). @openrampkit/core exports the metadata below.

Chain ids

Chain	CAIP-2 id	Native token	Notes
Ethereum	eip155:1	ETH
Base	eip155:8453	ETH	Default hop chain for two-leg pathways
Arbitrum	eip155:42161	ETH
Optimism	eip155:10	ETH
Polygon	eip155:137	POL
BNB Chain	eip155:56	BNB
Monad	eip155:143	MON
HyperEVM	eip155:999	HYPE
Tempo	eip155:4217	none (fees in USD stablecoins)	See Tempo
Tempo Testnet (Moderato)	eip155:42431	none (fees in pathUSD)	TEMPO_TESTNET. OpenRampSettlement deployed. Playground testnet mode
Solana	solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	SOL (9 decimals)	See Solana
Solana Devnet	solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1	SOL	Metadata and devnet USDC only
Robinhood Chain	eip155:4663	ETH	Arbitrum Orbit L2. No USDC in USDC yet.
Arbitrum Sepolia	eip155:421614	ETH	Testnet. Circle test USDC. Used by the settlement contract tests.
Robinhood Chain Testnet	eip155:46630	ETH	Testnet

CHAINS[id] gives name, nativeSymbol, nativeDecimals, testnet, stablecoinFees and explorerUrl. A chain that is not in the table still works when an adapter supports it. The UI then shows the CAIP-2 id as the name.

Token ids

• EVM token addresses are not case-sensitive. OpenRampKit stores them in lowercase.
• Solana mints are base58 and case-sensitive. OpenRampKit keeps them as given.
• normalizeToken(chain, token) and sameToken(chain, a, b) apply these rules. Use them when you compare tokens.

USDC[chain] gives the well-known USDC on each chain: Ethereum, Base, Arbitrum, Optimism, Polygon, Tempo, Solana, and Circle's test USDC on Arbitrum Sepolia. TESTNET_USDC gives Solana devnet USDC. isUsdc(chain, token) checks both.

Tempo

Tempo is a payments-first Layer 1 from Stripe and Paradigm. Its mainnet has been live since 18 March 2026.

Item	Value
Chain id	4217 (CAIP-2 eip155:4217, TEMPO_MAINNET)
Testnet	Moderato, chain id 42431 (TEMPO_TESTNET)
Public RPC	https://rpc.tempo.xyz (testnet https://rpc.moderato.tempo.xyz)
Explorer	https://explore.tempo.xyz
Token standard	TIP-20 (ERC-20 compatible, 6 decimals for USD stablecoins)
Fees	Paid in a USD stablecoin, not in a native gas token. pathUSD is the default fee token.
pathUSD	0x20c0000000000000000000000000000000000000 (TEMPO_PATH_USD)
USDC (bridged, "USDC.e" in Tempo docs)	0x20c000000000000000000000b9537d11c60e8b50 (TEMPO_USDC, also USDC['eip155:4217'])

What OpenRampKit supports on Tempo

• Relay. Relay supports Tempo with chain id 4217. Its token list has USDC, pathUSD, USDT0 and OUSD on Tempo. So these pathways work with the Relay adapter and a Tempo destination:
  • Card or local QR, then the Relay bridge hop from USDC on Base to USDC on Tempo.
  • "Pay with wallet" from any EVM chain or Solana.
  • "Transfer crypto" to a Relay deposit address.
  • Withdraw to a Tempo address.
• EVM wallet. Tempo is an EVM chain, so wagmiWallet signs Tempo transactions. Add the Tempo chain to your wagmi config (viem has a tempo chain, or use defineChain with the values above).
• Balances. eth_getBalance on Tempo does not return a real balance (Tempo has no native token). wagmiWallet does not show a native balance on chains with stablecoinFees: true. It shows USDC.
• Same-chain checks. The Relay adapter has a default Tempo RPC (https://rpc.tempo.xyz) for same-chain, same-token checks.

import { TEMPO_MAINNET, TEMPO_USDC } from '@openrampkit/core'

await openramp.sessions.create({
  userId: user.id,
  destination: { type: 'crypto', chain: TEMPO_MAINNET, token: TEMPO_USDC, symbol: 'USDC', decimals: 6, address: user.tempoAddress },
})

Gaps

• Fee token. A Tempo wallet pays fees in a USD stablecoin. The user needs a stablecoin balance on Tempo to send a transaction there (for example "Pay with wallet" from Tempo, or a withdraw from Tempo). Deposits to Tempo through Relay do not need a Tempo balance: Relay pays the destination side.
• Tempo transaction features. OpenRampKit sends standard EVM transactions. It does not use Tempo's own transaction type (fee token choice, batched calls, fee sponsorship).
• Direct onramps. MoonPay announced a Tempo onramp for USDC.e and pathUSD. The MoonPay adapter does not list a Tempo currency code yet, because we could not confirm the code. Until then, fiat reaches Tempo through the two-leg pathway (onramp to Base, then Relay).
• Testnet. Relay does not route the Moderato testnet. @openrampkit/core has its metadata (TEMPO_TESTNET), but no token addresses for it. OpenRampSettlement is deployed there. The playground testnet mode and NETWORK=tempo-testnet pnpm testnet:settle pay AlphaUSD (0x20c0000000000000000000000000000000000001) through it, with the mock localChain leg.

Sources: Tempo connection details, Tempo FAQ, Bridge stablecoins via Relay (Tempo docs), Relay GET /chains (chain 4217), MoonPay adds Tempo onramp.