# Construction API

The construction API facilitates actions such as generating and sending transactions to the chain. The available methods have been listed below.

## Construction

### Derive address from a public key

Method: **POST**

URL:  `/construction/derive`

Sample Request:

```javascript
{
    "network_identifier" :  {
            "blockchain" : "ont",
            "network" : "mainnet"
        },
    "public_key" : {
        "hex_bytes" : "<pubkey hex string>",
        "curve_type" : "secp256k1",
        "metadata" : {
            "type" : "hex"
        }
    }
}
```

{% hint style="info" %}
In the type `field`, the two address formats supported are **hex** and **base58.** The two supported curve types are `secp256k1` and `edwards25519`.
{% endhint %}

Sample Response:

```javascript
{
    "address" : "<address>",
    "metadata" : {
         "type" : "hex"
    }
}
```

### **Create a metadata request**

Method: **POST**

URL: `/construction/preprocess`

Sample Request:

```javascript
{
    "network_identifier": {
        "blockchain": "ont",
        "network": "privatenet"
    },
    "operations": [
        {
            "operation_identifier": {
                "index": 0
            },
            "type": "transfer",
            "status": "",
            "account": {
                "address": "AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud"
            },
            "amount": {
                "value": "-1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            }
        },
        {
            "operation_identifier": {
                "index": 1
            },
            "related_operations": [
                {
                    "index": 0
                }
            ],
            "type": "transfer",
            "status": "",
            "account": {
                "address": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
            },
            "amount": {
                "value": "1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            },
            "metadata": {
                "gasLimit": 20000,
                "gasPrice": 2500
            }
        }
    ],
    "metadata": {
        "payer": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
    }
}
```

Sample Response:

```javascript
{
    "options": {
        "amount": "1000000000",
        "decimals": 9,
        "fromAddr": "AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud",
        "gasLimit": 20000,
        "gasPrice": 2500,
        "payer": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS",
        "symbol": "ONT",
        "toAddr": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
    }
}
```

### **Fetch transaction** creation **metadata**

Method: **POST**

URL: `/construction/metadata`

Sample Request:

```javascript
{
  "network_identifier": {
    "blockchain": "ont",
    "network": "mainnet"
  },
  "options": {
    "method": "transfer"
  }
}
```

Sample Response:

```javascript
{
    "metadata": {
        "amount": "",
        "asset": "",
        "fromAddr": "",
        "gasLimit": "",
        "gasPrice": "",
        "payer": "",
        "toAddr": ""
    }
}
```

|   Field  |  Type  | Description                    |
| :------: | :----: | ------------------------------ |
|  amount  | String | Transaction amount             |
|   asset  | String | Asset type                     |
| fromAddr | String | `from` address                 |
| gasLimit | String | Gas limit, default value: 2000 |
| gasPrice | String | Gas price, default value: 2500 |
|   payer  | String | Default `from` address         |
|  toAddr  | String | `to` address                   |

### Generate an unsigned transaction and signing payloads

Method: **POST**

URL: `/construction/payloads`

Sample Request:

```javascript
{
    "network_identifier": {
        "blockchain": "ont",
        "network": "privatenet"
    },
    "operations": [
        {
            "operation_identifier": {
                "index": 0
            },
            "type": "transfer",
            "status": "",
            "account": {
                "address": "AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud"
            },
            "amount": {
                "value": "-1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            }
        },
        {
            "operation_identifier": {
                "index": 1
            },
            "related_operations": [
                {
                    "index": 0
                }
            ],
            "type": "transfer",
            "status": "",
            "account": {
                "address": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
            },
            "amount": {
                "value": "1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            },
            "metadata": {
                "gasLimit": 20000,
                "gasPrice": 2500
            }
        }
    ],
    "metadata": {
        "payer": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
    }
}
```

Sample Response:

```javascript
{
    "unsigned_transaction": "00d1b8c16889204e000000000000c409000000000000ffe723aefd01bac311d8b16ff8bfd594d77f31ee7100c66b14092118e0112274581b60dfb6fedcbfdcfc044be76a7cc814ffe723aefd01bac311d8b16ff8bfd594d77f31ee6a7cc8516a7cc86c51c1087472616e736665721400000000000000000000000000000000000000010068164f6e746f6c6f67792e4e61746976652e496e766f6b650000",
    "payloads": [
        {
            "hex_bytes": "a4a88f45b51e7aa01eedd0db3a7d7aff0a6e641256f3e073e8dbabb19358513f",
            "address": "AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud",
            "signature_type": "ecdsa"
        }
    ]
}
```

### Parse a transaction

Method: **POST**

URL: `/construction/parse`

Sample Request:

```javascript
{
    "network_identifier": {
        "blockchain": "ont",
        "network": "privatenet"
    },
    "signed" : false,
    "transaction":"00d10534aa05c409000000000000204e000000000000ffe723aefd01bac311d8b16ff8bfd594d77f31ee7100c66b14092118e0112274581b60dfb6fedcbfdcfc044be76a7cc814ffe723aefd01bac311d8b16ff8bfd594d77f31ee6a7cc8516a7cc86c51c1087472616e736665721400000000000000000000000000000000000000010068164f6e746f6c6f67792e4e61746976652e496e766f6b650000"
}
```

Sample Response:

```javascript
{
    "operations": [
        {
            "operation_identifier": {
                "index": 0
            },
            "type": "transfer",
            "status": "SUCCESS",
            "account": {
                "address": "AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud"
            },
            "amount": {
                "value": "-1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            }
        },
        {
            "operation_identifier": {
                "index": 1
            },
            "related_operations": [
                {
                    "index": 0
                }
            ],
            "type": "transfer",
            "status": "SUCCESS",
            "account": {
                "address": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
            },
            "amount": {
                "value": "1000000000",
                "currency": {
                    "symbol": "ONT",
                    "decimals": 9,
                    "metadata": {
                        "ContractAddress": "0100000000000000000000000000000000000000",
                        "TokenType": "Governance Token"
                    }
                }
            },
            "metadata": {
                "gasLimit": 20000,
                "gasPrice": 2500
            }
        }
    ],
    "signers": [],
    "metadata": {
        "payer": "Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS"
    }
}
```

### Create a transaction using signatures

Method: **POST**

URL: `/construction/combine`

Sample Request:

{% hint style="info" %}
In this sample request, the account `AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud` transfers 1 ONT to the account `Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS`, and the account `Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS` pays the transaction fee as the payer.
{% endhint %}

```javascript
{
	    "network_identifier":  {
            "blockchain": "ont",
            "network": "testnet"
        },
        "unsigned_transaction":"00d1594606d2c409000000000000204e000000000000ffe723aefd01bac311d8b16ff8bfd594d77f31ee7100c66b14092118e0112274581b60dfb6fedcbfdcfc044be76a7cc814ffe723aefd01bac311d8b16ff8bfd594d77f31ee6a7cc8516a7cc86c51c1087472616e736665721400000000000000000000000000000000000000010068164f6e746f6c6f67792e4e61746976652e496e766f6b650000",
        "signatures":[
        		{
	        	"signing_payload":{
	        		"address":"Af6xrG7WB9wUKQ3aRDXnfba2G5DXjqejMS",
	        		"hex_bytes":"2b371f76afde8a543fd0a6a58f2578281b3517e96c2a811114ea4c78e362b221",
	        		"signature_type":"ecdsa"
	        	},
	        	"public_key":{
	        		"hex_bytes":"02263e2e1eecf7a45f21e9e0f865510966d4e93551d95876ecb3c42acf2b68aaae",
	        		"curve_type":"secp256k1"
	        	},
	        	"signature_type":"ecdsa",
	        	"hex_bytes":"3b52bc592bbba306ca9368e2808d6eb1d14fe0c3e2c801294bf8ebe3a994b464e6888038b6411a78428f9020b9f43c9dbcada7f77c0307b3ce9a410d8d2b6fa6"
        	},
        	{
	        	"signing_payload":{
	        		"address":"AGc9NrdF5MuMJpkFfZ3MWKa67ds6H2fzud",
	        		"hex_bytes":"2b371f76afde8a543fd0a6a58f2578281b3517e96c2a811114ea4c78e362b221",
	        		"signature_type":"ecdsa"
	        	},
	        	"public_key":{
	        		"hex_bytes":"03944e3ff777b14add03a76fd6767aaf4a65c227ec201375d9118d4e6b272494c7",
	        		"curve_type":"secp256k1"
	        	},
	        	"signature_type":"ecdsa",
	        	"hex_bytes":"a6f29359a94db9725ceafa37012abd3a02cff41fe1b3ca6fb0f4c58e86cd2e214567a5f29682cd4432404ecb8ded644bfb9324fe0eb746fe53097ffed13d11b1"
        	}
        ]
}
```

Sample Response:

```javascript
{
    "signed_transaction": "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"
}
```

### Fetch the hash of a signed transaction

Method: **POST**

URL: `/construction/hash`

Sample Request:

```javascript
{
    "network_identifier": {
        "blockchain": "ont",
        "network": "privatenet"
    },
    "signed_transaction":"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"
}
```

Sample Response:

```javascript
{
    "transaction_hash": "cc45747a18862709f4ce50290ac331c94fb5ef6b608c36c90b00314884312b03"
}
```

### **Submit a signed transaction**

Method: **POST**

URL: `/construction/submit`

Sample Request:

```javascript
{
  "network_identifier": {
    "blockchain": "ont",
    "network": "mainnet"
  },
  "signed_transaction": "<signed tx hex>"
}
```

Sample Response:

```javascript
{
  "transaction_identifier": {
    "hash": "<tx hash>"
  },
  "metadata": {}
}
```