Submitting the Transaction

Once the user has signed the message and approved the token transfer, it’s time to construct the submit request to the Kima Transaction Backend. Use transactionValues returned by the /submit/fees endpoint.

Again, like for the message signing, the select the appropriate version based on whether the user is paying fees from the origin or target chain.

• If the user is paying fees from the origin, use transactionValues.feeFromOrigin.submitAmount.

• If the user is paying fees from the target, use transactionValues.feeFromTarget.submitAmount.

Submitting the Transaction

POST /submit Request Body:

• originAddress (Address): sending user address

• originChain (string): sending chain

• originSymbol (string): sending token symbol

• targetAddress (Address): receiving user address

• targetChain (string): receiving chain

• targetSymbol (string): receiving token symbol

• amount (bigint string): amount of token received by the target address

• fee (bigint string): amount of token that Kima consumes to pay gas fees for pulling & releasing token transactions

• decimals (number): the number of decimals for the bigint amounts

• options (string- JSON stringified object)

  • chargeFeeAtTarget (boolean): true if the user should pay fees on the target chain, false otherwise

  • feeId (string): the fee id obtained from /submit/fees

  • signature (string): the signature from the user's wallet from signing the message

• For Bitcoin transactions:

  • Set these to the empty string or zero for non-BTC transactions

  • htlcCreationHash (string): the tx hash locking the funds in the HTLC

  • htlcCreationVout (number): the output index of the locked funds in the HTLC creation transaction

  • htlcExpirationTimestamp (string): the timestamp when the HTLC contract expires and the user can reclaim the funds locked there

  • htclVersion (string)

  • senderPubKey (string): for bitcoin transactions this is the public key of the sender

See the list of chain short names in the Supported Blockchains section.

  const txValues = feeFromOrigin
    ? feeData.transactionValues.feeFromOrigin
    : feeData.transactionValues.feeFromTarget

  const response = await fetch(
    `${backendUrl}/submit`,
    {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        originAddress,
        originChain,
        targetAddress,
        targetChain,
        originSymbol,
        targetSymbol,
        amount: txValues.submitAmount.value.toString(),
        fee: feeData.feeTotalBigInt.value.toString(),
        decimals: txValues.submitAmount.decimals,
        htlcCreationHash: '',
        htlcCreationVout: 0,
        htlcExpirationTimestamp: '0',
        htlcVersion: '',
        senderPubKey: '',
        options: JSON.stringify({
          signature,
          feeId,
          chargeFeeAtTarget: !feeFromOrigin
        })
      })
  )

Make sure the decimals for the bigint amounts are all the same. You may need to convert the value for feeTotalBigint to the same decimals as the submitAmount before passing it to the backend.

Success Response:

• height: number

• txIndex: number

• code: number: error code; will be zero when successful

• transactionHash: string

• events: Event[]

  • type: string

  • attributes: Attribute[]

    • key: string

    • value: string

• rawLog?: string

• data?: MsgData[]

• msgResponses: Uint8Array

• gasUsed: bigint

• gasWanted: bigint

Get Transaction Id

The transaction Id will be needed to fetch the transaction status. The following code can be used to extract the Id from the submit response.

export function getTransactionId(submitResult: any): number {
  let txId = -1;
  if (result?.code !== 0) {
    return txId;
  }

  for (const event of result.events) {
    if (event.type === "transaction_requested") {
      for (const attr of event.attributes) {
        if (attr.key === "txId") {
          txId = attr.value;
        }
      }
    }
  }

  return txId;
}

Validation

If provided, the Kima Backend will use the url defined in the ENV var COMPLIANCE_URL to get the risk score for the origin and target user addresses. If the score is anything other than low it will respond with a 500 error.