exchange.IO("bridge.*", ...)

Cross-chain bridge (Across, Stargate, CCTP and others aggregated by LI.FI): lists the supported chains and tokens, quotes and simulates, moves tokens from this exchange object's chain to another EVM chain or Solana, and tracks delivery.

    
    
    
exchange.IO(k)

    
    
    
exchange.IO(k, chain)

    
    
    
exchange.IO(k, params)

    
    
    
exchange.IO(k, params, stateOverride)

    
    
    
exchange.IO(k, txHash, options)

    
    
    
exchange.IO(k, key)

Examples

• Quote and simulate bridging 0.01 ETH from this chain to Arbitrum (read-only, costs nothing).

  
      javascript
      
      
  function main() {
      var params = {toChain: "arb", fromToken: "ETH", toToken: "ETH", amount: 0.01}
      var q = exchange.IO("bridge.quote", params)
      if (!q) {
          Log("Quote failed:", GetLastError())
          return
      }
      Log("Via", q.toolName, "to", q.toChainName, "expected", q.toAmount, "at least", q.toAmountMin,
          "in about", q.executionDuration, "s")
      q.feeCosts.forEach(function (f) {
          Log("Fee:", f.name, f.amount, f.token, f.included ? "included in the quote" : "paid on top")
      })
      // when the wallet balance is short, give it a temporary 100 ETH for the simulation
      var ov = {}
      ov[exchange.IO("address")] = {balance: "0x56bc75e2d63100000"}
      var s = exchange.IO("bridge.simulate", q, ov)
      Log(s ? "Simulation passed, calling " + s.to : "Simulation failed: " + GetLastError())
  }
  

• The complete flow: quote → simulate → send → poll the progress every 20 seconds until delivered.

  
      javascript
      
      
  function main() {
      // bridge 20 USDC from this chain to this wallet on Arbitrum
      var params = {toChain: "arb", fromToken: "USDC", toToken: "USDC", amount: 20}
      var q = exchange.IO("bridge.quote", params)
      if (!q || !exchange.IO("bridge.simulate", q)) {
          Log("Quote or simulation failed:", GetLastError())
          return
      }
      var r = exchange.IO("bridge.send", q)
      if (!r) {
          Log("Send failed:", GetLastError())
          return
      }
      Log("Source transaction", r.txHash, "via", r.tool)
      while (true) {
          Sleep(20000)
          var st = exchange.IO("bridge.status", r.txHash, {toChain: "arb", bridge: r.tool})
          if (!st) {
              continue
          }
          Log(st.status, st.substatus || "")
          if (st.status == "DONE") {
              Log("Received", st.receiving.amount, st.receiving.token.symbol, st.receiving.txLink)
              break
          }
          if (st.status == "FAILED" || st.status == "INVALID") {
              Log("Bridge failed:", st.substatusMessage)
              break
          }
      }
  }
  

• List the supported chains and quote a transfer to Solana.

  
      javascript
      
      
  function main() {
      var chains = exchange.IO("bridge.chains")
      Log(chains.length, "chains supported, such as", chains[0].name, chains[0].key)
      // a Solana destination needs toAddress (a Solana address)
      var q = exchange.IO("bridge.quote", {toChain: "Solana", fromToken: "USDC", toToken: "USDC",
          amount: 50, toAddress: "YOUR_SOLANA_ADDRESS", order: "CHEAPEST"})
      Log(q ? [q.toolName, q.toAmount, q.toAmountMin] : GetLastError())
  }
  

Returns

Arguments

See Also

Remarks

The commands:

Keys of params (unknown keys are errors):

A quote is {tool, toolName, fromChain, toChain, toChainName, fromToken, toToken, fromAmount, toAmount, toAmountMin, fromAmountRaw, toAmountRaw, toAmountMinRaw, fromAmountUSD, toAmountUSD, slippage, toAddress, feeCosts, gasCosts, executionDuration, approvalAddress, steps, transactionId, request}: tool is the chosen bridge; amounts are in token units (*Raw in the smallest unit); toAmountMin is the amount guaranteed after slippage; feeCosts is [{name, amount, token, amountUSD, percentage, included}] (fees with included false are paid on top); gasCosts estimates source-chain gas; executionDuration is the expected time in seconds; approvalAddress is the contract to approve (null for the native coin); steps lists the steps (cross bridges, swap swaps); request echoes the parameters. A bridge.simulate result also has simulated (true), to, value and walletBalance, plus allowanceOverride when an allowance was supplied.

bridge.simulate: a short token allowance is supplied as unlimited through a state override (as in exchange.IO("simulate", ...)); balances are not, so when bridging the native coin give the wallet a balance in stateOverride. A failure caused by a short balance reports the wallet balance.

bridge.send steps: re-quote → check the balance → approve LI.FI's approvalAddress when the token allowance is short (following exchange.IO("approve") exact/max, resetting USDT-like tokens to zero first, waiting for the approval to be mined and re-quoting after it) → simulate with eth_call → sign and broadcast. The gas limit is the larger of the estimate × gasMultiplier and LI.FI's suggestion. It returns {txHash, tool, fromChain, toChain, toChainName, fromToken, toToken, fromAmount, toAmount, toAmountMin, toAddress, value, transactionId}, txHash being the source-chain transaction, whose receipt exchange.IO("receipt", ...) returns. Given a quote it re-quotes from its request; the new quote applies and toAmountMin is enforced on chain.

bridge.status returns {status, substatus, substatusMessage, tool, sending, receiving, fromAddress, toAddress, explorer, bridgeExplorer}: status is NOT_FOUND, INVALID, PENDING, DONE or FAILED; when DONE, substatus is COMPLETED (delivered as quoted), PARTIAL (a different token arrived) or REFUNDED (returned to the source chain); sending and receiving are {txHash, txLink, chainId, amount, amountRaw, token, timestamp}, receiving being what actually arrived. Right after broadcasting LI.FI may not have indexed it yet and returns NOT_FOUND; keep polling (every 10 to 30 seconds); toChain and bridge (the tool of the send result) in options speed up the lookup.

Bridging is asynchronous: delivery takes seconds to tens of minutes (see executionDuration) and must be confirmed by polling bridge.status; cross-VM transfers (EVM↔Solana) require toAddress, and funds sent to a wrong address cannot be recovered; the destination wallet needs gas to use what arrives. Without an API key LI.FI limits by outgoing IP (/quote 75 times per 2 hours, used once each by bridge.quote, bridge.simulate and bridge.send), shared by the strategies on a docker; with a key the limit is 100 per minute. Test with a small amount first.