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LI.FI offers bridging between Tron and other supported ecosystems, such as EVM chains and Solana.
Tron chainId in LI.FI is 728126428 (chain key TRN).Native TRX is represented as T9yD14Nj9j7xAB4dbGeiX9h8unkKHxuWwb (6 decimals). TRC20 tokens are addressed by their Base58 contract address (T...).Tron addresses are Base58 and case-sensitive. Always pass them exactly as returned by the API. The hex form (41...) is not accepted.
Same-chain swaps on Tron are not supported yet. Quotes with Tron as the source chain are always cross-chain.

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Requesting a quote

A quote for Tron can be requested using the same endpoints as EVM. Only the chain ids, token addresses and the transaction data differ.
fromAddress when the source chain is Tron must be a Base58 T... account address.toAddress when Tron is the destination chain is a Base58 T... address. When bridging out of Tron, toAddress is a regular address on the destination chain (for example an EVM address).

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Token approvals

Sending a TRC20 token requires a token allowance: the executing contract pulls the tokens from your account, so give an allowance to the step’s estimate.approvalAddress for at least fromAmount before executing. Native TRX is passed as the transaction’s call value and needs no approval. To check whether a route needs an approval, scan the quote’s includedSteps: whenever a step’s estimate.skipApproval is not true, approve that step’s estimate.approvalAddress.
An approval is a separate Tron transaction (TRC20 approve(spender, amount)). Submit it and wait for it to be confirmed before broadcasting the LI.FI transaction.

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Executing a transaction

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Transaction data

transactionRequest carries the unsigned Tron transaction in two forms:
  • data — the hex-encoded protobuf raw_data of an unsigned TriggerSmartContract transaction (the raw_data_hex of a Tron node), prefixed with 0x.
  • customData.tronTransaction — the same transaction as a TronWeb transaction object: { visible, txID, raw_data, raw_data_hex }. customData.contractType is TriggerSmartContract.
Inside the object, raw_data_hex and txID are plain lowercase hex without the 0x prefix, so data equals 0x + raw_data_hex. to is the LI.FI contract on Tron, value is the TRX call value in SUN and gasLimit is the transaction’s fee_limit in SUN (see Gas). Both are hex-encoded strings, matching raw_data.fee_limit in the transaction object. To execute the transaction with TronWeb:
  1. Request the transaction data through the regular quote flow.
  2. Sign customData.tronTransaction with the sender account’s key.
  3. Broadcast the signed transaction to the Tron network.
data alone is enough to rebuild the transaction without TronWeb: the transaction id is the SHA-256 hash of the raw_data bytes (strip the 0x prefix first), and the signature is made over that id. customData.tronTransaction saves you the deserialization.
Transaction validity windowThe transaction is valid until raw_data.expiration, about 10 minutes after it was built. The network rejects a transaction broadcast after its expiration.
  • Sign and broadcast promptly after receiving the transaction data.
  • Request a new transaction if the one you hold is stale.
  • If signing takes longer (for example with an MPC signer), extend the expiration before signing. TronWeb recomputes txID and raw_data_hex for you:
The expiration cannot be more than 24 hours after the current block. Do not modify any other field of raw_data.

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Gas

Tron charges bandwidth and energy. The estimated costs are returned in the step’s estimate.gasCosts as two SEND entries in SUN (TRX, 6 decimals): one for bandwidth and one for energy. Resources staked by the sender account are consumed first; the remainder is burned in TRX. transactionRequest.gasLimit is the transaction’s fee_limit: the maximum TRX the transaction is allowed to burn for energy. It is a safety ceiling, not the expected cost.

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Status tracking

Transaction status can be tracked using the regular status tracking flow.
When polling /status for a transaction that originates on Tron, always pass fromChain=TRN (or the Tron chain id 728126428). Tron transaction hashes are 64-character hex strings and are otherwise indistinguishable from Bitcoin transaction hashes.