Create fixed rate transaction

After a successful call of createFixTransaction method, you get a unique ID to track the transaction status and a payin address for user to send money to.

info

The amountExpectedTo parameter value should be understood as a payout amount to the user before withholding the networkFee. To calculate the exact payout amount, deduct the networkFee value from amountExpectedTo

HTTP request

post

/v2/#createFixTransaction

Request

Header parameters

Requires authentification.

Body parameters

Requires JSON-RPC 2.0 protocol request body.

warning

Although amountFrom and amountTo are optional parameters, it is required to set one of them. If you provide none or both, the request will result in error.

The params parameter schema:

Name	Type	Required	Description
from	string	true	Payin currency ticker (in lowercase).
to	string	true	Payout currency ticker (in lowercase).
rateId	string	true	Rate ID that you get from getFixRate/getFixRateForAmount requests.
address	string	true	Recipient address.
amountFrom	string	false	Amount of currency that user is going to send.
amountTo	string	false	Amount user wants to receive.
extraId	string	false	Additional ID for address for currencies that use additional ID for transaction processing.
refundAddress	string	true	Address of the wallet to refund in case of any technical issues during the exchange. The currency of the wallet must match with the from currency.
refundExtraId	string	false	extraId for refundAddress.
fromAddress	string	false	Address of the wallet from which the user will send payin.
fromExtraId	string	false	extraId for fromAddress.
userMetadata	string	false	Escaped JSON. You can use userMetadata to include any additional parameters for customization purposes. To use this feature, please contact us at [email protected].

Sample request payload

application/json

{
  "jsonrpc": "2.0",
  "id": "test",
  "method": "createFixTransaction",
  "params": {
    "from": "eth",
    "to": "xrp",
    "address": "rwpMvf*************PQqWDwQyHUW",
    "extraId": "209****48",
    "amountFrom": "0.2",
    "rateId": "f3dd48106a63b*********b7ab5413d32c7b96301a7e83",
    "refundAddress": "0x576ea9d3**********3d3fd5f1499a0"
  }
}

Sample request payload with the userMetadata

application/json

{
  "jsonrpc": "2.0",
  "id": "test",
  "method": "createFixTransaction",
  "params": {
    "from": "eth",
    "to": "xrp",
    "address": "rwpMvf*************PQqWDwQyHUW",
    "extraId": "209****48",
    "amountFrom": "0.2",
    "rateId": "f3dd48106a63b*********b7ab5413d32c7b96301a7e83",
    "refundAddress": "0x576ea9d3**********3d3fd5f1499a0",
    "userMetadata": "{\"param1\": 50, \"param2\": \"string\", \"param3\": \"50.5189\"}"
  }
}

Sample cURL

curl --location --request POST 'https://api.changelly.com/v2' \
--header 'X-Api-Key: {{apiKey}}' \
--header 'X-Api-Signature: {{sign}}' \
--data-raw '{
  "id": "test",
  "jsonrpc": "2.0",
  "method": "createFixTransaction",
  "params": {
    "from": "btc",
    "to": "eth",
    "address": "0xee*******5E3DFc214",
    "amountFrom": "1",
    "rateId": "f3dd48106a63b*********b7ab5413d32c7b96301a7e82",
    "refundAddress": "1Bvjij5653y9****BGPuQBPzTZpb"
  }
}'

Response

Response parameters

Requires JSON-RPC 2.0 protocol response body.

The result parameter schema:

Name	Type	Description
id	string	Transaction ID. Could be used in getStatus method.
type	string	Type of transaction. Always fixed in this method.
payinAddress	string	Address for a user to send coins to.
payinExtraId	string	Extra ID for payinAddress in case it is required. Note: If the payinExtraId parameter is returned in the response and is not null, it is required for user to send the funds to the payinAddress specifying extraId. Otherwise, the transactions will not be processed and the user will need to get a refund through technical support.
payoutAddress	string	Address where the exchange result will be sent to.
payoutExtraId	string	Extra ID for payoutAddress in case it is required.
refundAddress	string	Address of the wallet to refund in case of any technical issues during the exchange. The currency of the wallet must match with the from currency.
refundExtraId	string	Extra ID for refundAddress.
amountExpectedFrom	number	The amountFrom value from createFixTransaction request.
amountExpectedTo	string	The amountTo value from getFixRateForAmount response. This is the estimated payout amount of currency before withholding the network fee.
status	string	Transaction status. Will always be new when transaction is created. If you reference the same transaction using the getStatus or getTransactions method, you'll get the waiting status as an equivalent to new.
payTill	string	Indicates time until which user needs to make the payment.
currencyTo	string	Payout currency ticker.
currencyFrom	string	Payin currency ticker.
createdAt	integer	Time in timestamp format (microseconds) when the transaction was created.
networkFee	string	Commission taken by the network from the amount sent to the user. Displayed in payout currency.

warning

The result scheme parameter trackUrl is deprecated. You can retrieve the actual status and transaction data from the getStatus and getTransactions methods.

Sample response

application/json

{
  "jsonrpc": "2.0",
  "id": "test",
  "result": {
    "id": "149a****m90",
    "type": "fixed",
    "status": "new",
    "payTill": "2022-10-31T16:41:55.000000271+00:00",
    "currencyFrom": "btc",
    "currencyTo": "eth",
    "payinExtraId": null,
    "payoutExtraId": null,
    "refundAddress": "1Bvjij5653y9r********QBPzTZpb",
    "amountExpectedFrom": "1.00000000",
    "amountExpectedTo": "32.277489930000000000",
    "payinAddress": "3EkyEjzs********vZ95AyTM",
    "payoutAddress": "0xeee031413*******B8Cf5E3DFc214",
    "createdAt": 1664894262000000,
    "networkFee": "0.000515"
  }
}

Error response

Error response parameters

Check the error response schema.

Error codes

Code	Message	Description
-32600	Invalid amount: maximal amount is {max_amount}	The attempt to exchange more currency than a maximal amount.
-32602	Invalid currency: {currency} temporary disabled	This currency is currently disabled.
-32602	Invalid currency: {currency} temporary disabled for fix rate transactions	This currency is currently disabled for fix-rate transactions.
-32602	Invalid currency: {currency} is temporary disabled on API as output currency	This currency is currently disabled on API as an output currency.
-32602	Invalid currency: {currency} is temporary disabled on API as input currency	This currency is currently disabled on API as an input currency.
-32602	Invalid currency: {currency} not found	This currency is not listed on Changelly or the ticker is invalid.
-32602	Parameter {param} is invalid	You've specified an invalid parameter.
-32602	Error: Invalid address	You've specified an invalid payout address.
-32602	Error: Invalid refund address	You've specified an invalid refund address.
-32602	Error: rateId was expired or already used. Use method getFixRateForAmount to generate new rateId	New rateId has to be generated.
-32603	Internal Error or Error	Most likely, the problem is on our side. Further investigation is required.