Send a simple JSON or YAML payload that can:

  • Compile and deploy contracts from in-line Solidity source code
  • Deploy contracts from bytecode
  • Asynchronously deliver transactions to your ethereum node over our Kafka backbone
  • Invoke solidity transactions without needing to first install an ABI

You get a response immediately, including an id that you can query for results in the receipt store later.

The same reliable transport as is used on POST methods of the installed REST Gateway generated interfaces, when kld-sync is unset.

Ideal for use as a webhook endpoint for an integration tool that can emit sevents over HTTPS. Also useful if your application wants to construct the full details for the transaction to sent to a contract, or install a new contract, without first teaching the REST API Gateway about the Solidity interface (ABI).


There are two variations of the webhook:

  • Fire & forget on / and /fasthook: responds as soon as the message is sent to the Kafka client library
  • Kafka acknowledged on /hook: responds only once Kafka has acknowledged receipt of the message


You can send either JSON or YAML, containing the following fields:

Field type Description
headers object Required: Headers
headers.type string Required: DeployContract or SendTransaction
from string Required: The hex from address to sign the transaction (0x optional)
to string The target hex address (0x optional) - required for SendTransaction only
methodName string The method to invoke - required for SendTransaction only
params array Array of input parameters, with type and value
params[].type string Ethereum type such as uint256 for the parameter
params[].value mixed Value for the parameter, in an appropriate type for the input.
We recommend strings for numeric types, but accept either
soldity string Solidity contract source (SendTransaction only)
contractName string When there are multiple contracts in the compiler output,
this field is required to select the contract to deploy
compilerVersion string Compiler to use. Default: 0.4 (for compatibility)
Recommend setting to 0.5
compiled base64 Pre-compiled contract binary - instead of solidity
gas string Maximum gas to consume.
Recommend leaving unset for automatic gas estimation
gasPrice string Optionally offer a non-zero gas price for the transaction
value string Optionally send some of the chain's native Ether with the transaction
nonce string Optionally set an explicit nonce for the transaction.
Recommend leaving unset for automatic nonce management
privateFrom string Tessera / Orion Private Transactions: private-from address
privateFor array Tessera / Orion Private Transactions: private-for addresses

Example Contract Deployment Transaction

    type: DeployContract
from: "0xb863185C6361A226Edc3Ec11EB891a2CfDDc5685"
  - type: "uint256"
    value: "12345"
compilerVersion: '0.5'
solidity: |-
    pragma solidity >=0.4.24 <0.6.0;
     * @title Simple Storage
     * @dev Read and write values to the chain
    contract simplestorage {
        uint public storedData;
         * @dev Constructor sets the default value
         * @param initVal The initial value
        constructor(uint initVal) public {
            storedData = initVal;
         * @dev Set the value
         * @param x The new value
        function set(uint x) public {
            storedData = x;
         * @dev Get the value
        function get() public view returns (uint retVal) {
            return storedData;

Example Method Invocation Transaction

    type: SendTransaction
from: "0xb863185C6361A226Edc3Ec11EB891a2CfDDc5685"
to: "0xdceb21933100f4c48d0365db73506ea2dd91e07b"
methodName: set
  - type: "uint256"
    value: "99999"

Example Confirmation Response

  "sent": true,
  "id": "4696c9f7-2163-4237-7b58-0884fff5fbaf",
  "msg": "u0j6rld2ka-u0uk478rin-requests:0:1"