Through this endpoint customers can prepare an unsigned UTXO-based transaction from a single funding address. The service selects the necessary UTXOs from that address, estimates the fee by the chosen priority, and returns the unsigned inputs (with the sighashes to sign) and outputs. The funding address pays the fee and receives the change.

This is a paid endpoint and it works for both mainnet and testnet networks.

Path Parameters

blockchain string Required

Represents the specific blockchain protocol name, e.g. Bitcoin.

network string Required

Represents the name of the blockchain network used; e.g. "mainnet" is the live network with actual data while "testnet" is a test network.

Query Parameters

context string Optional

In batch situations the user can use the context to correlate responses with requests. This property is present regardless of whether the response was successful or returned as an error. context is specified by the user.

Request Body Schema application/json

context string Optional

data object Required

item object Required

additionalData string Optional

Represents an optional free-text note attached to the transaction request (embedded as OP_RETURN data).

locktime integer Optional

Represents the earliest time or block a transaction may be added to the blockchain.

fromAddress string Required

Represents the single funding address. It funds the outputs, pays the transaction fee and receives the change.

recipients array Items (object) Required

Object array representation of the transaction's recipients. Each item specifies a recipient address and the amount it should receive.

address string Required

Represents the specific recipient's address.

amount string Required

Represents the specific amount the recipient receives, in the main denomination (BTC).

feeOptions object Required

Specifies the fee details for the transaction.

priority string Optional

Represents the fee priority of the transaction, i.e. how quickly it should be mined.

exactAmount string Optional

Represents an exact fee amount to use, in the main denomination. When set, it overrides the priority-based estimate.

prepareStrategy string Optional

Represents the UTXO-selection strategy.

replaceable boolean Optional

Represents whether the transaction is replaceable (BIP-125 Replace-By-Fee).

Default : false

Response Schema

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

data object Required

item object Required

fee object Optional

The total fee of the transaction.

amount string Optional

The total fee amount, in the main denomination.

0.0000035

unit string Optional

The denomination of the fee amount.

BTC

feePerByte object Optional

The fee per byte used to compute the total fee.

amount string Optional

The fee-per-byte amount, in the main denomination.

0.00000001

unit string Optional

The denomination of the fee-per-byte amount.

BTC

size integer Optional

The estimated size of the transaction in bytes.

314

version integer Optional

The transaction's version number.

locktime integer Optional

The transaction's locktime.

additionalData string Optional

The optional free-text note attached to the transaction.

yourAdditionalDataHere

inputs array Items (object) Optional

Object array of the transaction's selected inputs, each with the hash (sighash) that must be signed.

address string Optional

The address the input is spent from.

tb1q7cer5fh3w656jpe30gudzjg05j0kmd48jwxhzh

outputIndex integer Optional

The index of the referenced output in the source transaction.

satoshis integer Optional

The value of the input, in satoshis.

76772

script string Optional

The locking script of the referenced output.

0014f6323a26f176a9a907317a38d1490fa49f6db6a7

sighash string Optional

The hash that must be signed for this input.

737a05f70bb0ff41adb2328585374804675da49d19d72a346569a01c180083db

transactionId string Optional

The id of the source transaction of the input.

8347b87d6956dc5c0bccf7f40227c7570d1bd66480fc38e660079a18c3bc21e1

outputs array Items (object) Optional

Object array of the transaction's outputs (recipients plus the change back to the sender).

address string Optional

The recipient (or change) address of the output.

tb1qsf7w5q7pnrumkm6r9zct4ls7504gxl4re9fag0

satoshis integer Optional

The value of the output, in satoshis.

50000

script string Optional

The locking script of the output.

0014827cea03c198f9bb6f4328b0bafe1ea3ea837ea3

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

code string Required

Specifies an error code, e.g. error 404.

uri_not_found

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The specified URI has not been found. Check the URI and try again.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

limit_greater_than_allowed

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

You have reached the allowed limit. The maximum number of items for this endpoint is {limit}, please use the specific pagination attributes to get the items in portions.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

invalid_pagination

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The pagination attributes that have been used are invalid. Please check the Documentation to see details on pagination.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

code string Required

Specifies an error code, e.g. error 404.

missing_api_key

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The specific authorization header (API Key) is missing, please check our Authorization section in our Documentation.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

invalid_api_key

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The provided API key is invalid. Please, generate a new one from your Dashboard.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

insufficient_credits

code string Required

Specifies an error code, e.g. error 404.

insufficient_credits

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

You have insufficient credits. Please upgrade your plan from your Dashboard or contact our team via email.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

code string Required

Specifies an error code, e.g. error 404.

banned_ip_address

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

This IP address has been banned. To check the reason for that, please contact our team via email.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

endpoint_not_allowed_for_plan

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

This endpoint is not available for your current subscription plan, please upgrade your plan to be able to use it.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

endpoint_not_allowed_for_api_key

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

This endpoint is not available for your API key.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

code string Required

Specifies an error code, e.g. error 404.

feature_mainnets_not_allowed_for_plan

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

Mainnets access is not available for your current subscription plan, please upgrade your plan to be able to use it.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

invalid_data

code string Required

Specifies an error code, e.g. error 404.

invalid_data

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The data provided seems to be invalid.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

unsupported_media_type

code string Required

Specifies an error code, e.g. error 404.

unsupported_media_type

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The selected Media Type is unavailable. The Content-Type header should be 'application/json'.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

invalid_request_body_structure

code string Required

Specifies an error code, e.g. error 404.

invalid_request_body_structure

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

Your request body for POST requests must have a structure of { data: { item: [...properties] } }

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

request_limit_reached

code string Required

Specifies an error code, e.g. error 404.

request_limit_reached

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

The request limit has been reached. There can be maximum {requests} requests per {seconds} second(s) made. Please contact our team via email if you need more or upgrade your plan.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

apiVersion string Required

Specifies the version of the API that incorporates this endpoint.

2024-12-12

requestId string Required

Defines the ID of the request. The requestId is generated by Crypto APIs and it's unique for every request.

601c1710034ed6d407996b30

context string Optional

yourExampleString

error object Required

unexpected_server_error

code string Required

Specifies an error code, e.g. error 404.

unexpected_server_error

message string Required

Specifies the message of the error, i.e. why the error was returned, e.g. error 404 stands for “not found”.

An unexpected server error has occurred, we are working to fix this. Please try again later and in case it occurs again please report it to our team via email.

details array Items (object) Optional

attribute string Required

Specifies an attribute of the error by name.

attribute which content caused the error

message string Required

Specifies the details of an attribute as part from the error.

message describing the error

Credits Cost

Blockchain protocol	Credits for 1 Results
Default Cost	530
Bitcoin	520
Litecoin	583
Dogecoin	583
Dash	583
Zcash	689
Bitcoin Cash	689

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               {
    "context": "yourExampleString",
    "data": {
        "item": {
            "additionalData": "yourAdditionalDataHere",
            "locktime": 0,
            "fromAddress": "tb1q7cer5fh3w656jpe30gudzjg05j0kmd48jwxhzh",
            "recipients": [
                {
                    "address": "tb1qsf7w5q7pnrumkm6r9zct4ls7504gxl4re9fag0",
                    "amount": "0.0005"
                }
            ],
            "feeOptions": {
                "priority": "standard",
                "exactAmount": "0.00001"
            },
            "prepareStrategy": "minimize-dust",
            "replaceable": false
        }
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "data": {
        "item": {
            "fee": {
                "amount": "0.0000035",
                "unit": "BTC"
            },
            "feePerByte": {
                "amount": "0.00000001",
                "unit": "BTC"
            },
            "size": 314,
            "version": 2,
            "locktime": 0,
            "additionalData": "yourAdditionalDataHere",
            "inputs": [
                {
                    "address": "tb1q7cer5fh3w656jpe30gudzjg05j0kmd48jwxhzh",
                    "outputIndex": 1,
                    "satoshis": 76772,
                    "script": "0014f6323a26f176a9a907317a38d1490fa49f6db6a7",
                    "sighash": "737a05f70bb0ff41adb2328585374804675da49d19d72a346569a01c180083db",
                    "transactionId": "8347b87d6956dc5c0bccf7f40227c7570d1bd66480fc38e660079a18c3bc21e1"
                }
            ],
            "outputs": [
                {
                    "address": "tb1qsf7w5q7pnrumkm6r9zct4ls7504gxl4re9fag0",
                    "satoshis": 50000,
                    "script": "0014827cea03c198f9bb6f4328b0bafe1ea3ea837ea3"
                }
            ]
        }
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "uri_not_found",
        "message": "The specified URI has not been found. Check the URI and try again.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "limit_greater_than_allowed",
        "message": "You have reached the allowed limit. The maximum number of items for this endpoint is {limit}, please use the specific pagination attributes to get the items in portions.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "invalid_pagination",
        "message": "The pagination attributes that have been used are invalid. Please check the Documentation to see details on pagination.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "missing_api_key",
        "message": "The specific authorization header (API Key) is missing, please check our Authorization section in our Documentation.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "invalid_api_key",
        "message": "The provided API key is invalid. Please, generate a new one from your Dashboard.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "insufficient_credits",
        "message": "You have insufficient credits. Please upgrade your plan from your Dashboard or contact our team via email.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "banned_ip_address",
        "message": "This IP address has been banned. To check the reason for that, please contact our team via email.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "endpoint_not_allowed_for_plan",
        "message": "This endpoint is not available for your current subscription plan, please upgrade your plan to be able to use it.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "endpoint_not_allowed_for_api_key",
        "message": "This endpoint is not available for your API key.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "feature_mainnets_not_allowed_for_plan",
        "message": "Mainnets access is not available for your current subscription plan, please upgrade your plan to be able to use it.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "invalid_data",
        "message": "The data provided seems to be invalid.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "unsupported_media_type",
        "message": "The selected Media Type is unavailable. The Content-Type header should be 'application/json'.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "invalid_request_body_structure",
        "message": "Your request body for POST requests must have a structure of { data: { item: [...properties] } }",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "request_limit_reached",
        "message": "The request limit has been reached. There can be maximum {requests} requests per {seconds} second(s) made. Please contact our team via email if you need more or upgrade your plan.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

{
    "apiVersion": "2024-12-12",
    "requestId": "601c1710034ed6d407996b30",
    "context": "yourExampleString",
    "error": {
        "code": "unexpected_server_error",
        "message": "An unexpected server error has occurred, we are working to fix this. Please try again later and in case it occurs again please report it to our team via email.",
        "details": [
            {
                "attribute": "attribute which content caused the error",
                "message": "message describing the error"
            }
        ]
    }
}

Prepare Transaction From Address UTXO

Path Parameters

Query Parameters

Request Body Schema application/json

Response Schema

Credits Cost

Security schema

URL Schema

Request