Javascript

For successful transaction processing, please include a system transfer tip to one of our designated tip addresses

JavaScript (using fetch)

async function makeRequest() {
  const url = "http://lon.block0.wtf/";
  const payload = {
    base64_tx: "<BASE64_ENCODED_TRANSACTION>"
  };
  
  try {
    const response = await fetch(url, {
      method: "POST",
      headers: {
        "Content-Type": "application/json"
      },
      body: JSON.stringify(payload)
    });
    
    const data = await response.text();
    console.log(`Status: ${response.status}`);
    console.log(`Response: ${data}`);
  } catch (error) {
    console.error("Error:", error);
  }
}

Javascript (using axios)

const axios = require('axios');

async function makeRequestWithAxios() {
  const url = "http://lon.block0.wtf/";
  const payload = {
    base64_tx: "<BASE64_ENCODED_TRANSACTION>"
  };
  
  try {
    const response = await axios.post(url, payload, {
      headers: {
        "Content-Type": "application/json"
      }
    });
    
    console.log(`Status: ${response.status}`);
    console.log(`Response: ${response.data}`);
  } catch (error) {
    console.error("Error:", error.message);
  }
}

If you're sending with blockhash in your TX, please ensure to use commitment level finalized.