Call a Contract Method

Once your contract is registered, you can interact with it by calling a method that changes state. This guide shows you how to send a transaction to a deployed contract using FSCO’s API.

Prerequisites

Before you begin, ensure:

• You have uploaded the contract ABI
• The deployment is registered
• You know the deploymentId and method name
• You have a wallet to sign and send the transaction

Endpoint

POST /v2/contract/deployment/{id}/call

Request Parameters

{
  "walletId": "your-wallet-id",
  "method": "transfer",
  "params": ["0xreceiver", "1000000000000000000"]
}

The request requires:

• walletId: The FSCO wallet ID that will sign and send the transaction
• method: The name of the method to call (must exist in the ABI)
• params: An array of arguments in the same order as the method signature

Example Request

cURL

call-method.sh

curl -X POST https://api.fsco.io/v2/contract/deployment/{{deploymentId}}/call \
  -H "Authorization: Bearer $FSCO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "walletId": "{{walletId}}",
    "methodName": "transfer",
    "paramCollection": ["0xreceiver", "1000000000000000000"],
    "isShared": false
  }'

TypeScript

call-method.ts

import axios from 'axios';

const FSCO_API_KEY = process.env.FSCO_API_KEY;

const callMethod = async () => {
  const response = await axios.post(
    'https://api.fsco.io/v2/contract/deployment/{{deploymentId}}/call',
    {
      walletId: '{{walletId}}',
      methodName: 'transfer',
      paramCollection: ['0xreceiver', '1000000000000000000'],
      isShared: false
    },
    {
      headers: {
        Authorization: `Bearer ${FSCO_API_KEY}`,
        'Content-Type': 'application/json'
      }
    }
  );

  console.log('Contract method called:', response.data);
};

callMethod();

Python

call-method.py

import requests
import os

FSCO_API_KEY = os.getenv("FSCO_API_KEY")

headers = {
    "Authorization": f"Bearer {FSCO_API_KEY}",
    "Content-Type": "application/json",
}

payload = {
    "walletId": "{{walletId}}",
    "methodName": "transfer",
    "paramCollection": ["0xreceiver", "1000000000000000000"],
    "isShared": False,
}

response = requests.post(
    "https://api.fsco.io/v2/contract/deployment/{{deploymentId}}/call",
    json=payload,
    headers=headers,
)

print("Contract method called:", response.json())

.NET

call-method.cs

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        var apiKey = Environment.GetEnvironmentVariable("FSCO_API_KEY");

        var client = new HttpClient();
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiKey);

        var json = @"{
            ""walletId"": ""{{walletId}}"",
            ""methodName"": ""transfer"",
            ""paramCollection"": [""0xreceiver"", ""1000000000000000000""],
            ""isShared"": false
        }";
        var content = new StringContent(json, Encoding.UTF8, "application/json");

        var response = await client.PostAsync("https://api.fsco.io/v2/contract/deployment/{{deploymentId}}/call", content);
        var responseString = await response.Content.ReadAsStringAsync();

        Console.WriteLine("Contract method called: " + responseString);
    }
}

Response

JSON

response.json

{
  "queryId": "uuid-string"
}

Important Notes

• Ensure the wallet has sufficient native tokens to cover gas
• Use a separate guide if you only want to query a method without changing state
• The transaction will be broadcast to the chain immediately

Next Steps

• Query a Contract
• Contract Module Overview
• Contract API Reference