Here are some quick snippets that help when you want to get info from Blockchain.

1. This will query the blockchain endpoint on a given address and give a current number of transactions made by that address. Which will be nonce of the address. Remember that nonce always starts with 0

curl https://go.getblock.io/58ccb1cf74404a4d9c25c6c81dea36b8 -X POST -H "Content-Type: application/json" --data '{"method":"eth_getTransactionCount","params":["0x14D580158D276bd2C3bBf02dC91276aFa19D2169", "latest"],"id":1,"jsonrpc":"2.0"}'

2. This will query the chain and give you transactions qued on a particular address, so if something is pending this should be listed here.

curl -X POST -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' https://go.getblock.io/58ccb1cf74404a4d9c25c6c81dea36b8 | jq '.result.queued | .["0x14D580158D276bd2C3bBf02dC91276aFa19D2169"]'

3. To do some read-only RPC calls on the chain you can use this snippet

curl -s -X POST -H 'Content-Type: application/json' --data '{"jsonrpc":"2.0","method":"eth_call","params":[ { "from": "<account_address>", "to": "<contract_address>", "data": "0x053f14da", "gas": "0x1e8480" }, "latest" ], "id":"1" }' http://geth-swap.private-localstorev2.testnet.internal

4. To do some writing on the chain, you would need to call this, however, it's important to note that using eth_sendTransaction requires the sender to be unlocked
(geth --unlock "0xYourAccountAddress") on the Ethereum node handling the request, which poses security risks.

curl -s -X POST -H 'Content-Type: application/json' --data '{"jsonrpc":"2.0","method":"eth_sendTransaction","params":[ { "from": "0x62cab2b3b55f341f10348720ca18063cdb779ad5", "to": "0x4370ed4d3a3ffb5be6b5ac7a9f0b781f24b092fa", "data": "0x053f14da", "gas": "0x1e8480" } ], "id":"1" }' http://geth-swap.ph4.testnet.internal

more secure way to do this would be to sign a message locally and send the data like the below

curl -X POST -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"eth_sendRawTransaction","params":["SIGNED_TRANSACTION_DATA"],"id":1}' https://rinkeby.infura.io/v3/YOUR_INFURA_PROJECT_ID

To get signed transaction data you should run the script locally with the private key

// Import ethers library
const { ethers } = require('ethers');

// Define provider using Infura. Replace YOUR_INFURA_PROJECT_ID with your actual Infura Project ID.
const provider = new ethers.providers.JsonRpcProvider('https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID');

// Define the signer's private key
// WARNING: Never hardcode your real private key in production code.
const senderPrivateKey = 'YOUR_PRIVATE_KEY'; // Replace YOUR_PRIVATE_KEY with the actual private key
const wallet = new ethers.Wallet(senderPrivateKey, provider);

// Define the transaction
async function main() {
  let nonce = await provider.getTransactionCount(wallet.address, "latest"); // Get current nonce
  const tx = {
    to: "0xRecipientAddress", // Replace 0xRecipientAddress with the recipient's address
    value: ethers.utils.parseEther("0.01"), // Sending 0.01 ETH
    nonce: nonce,
    // Ethers.js can automatically estimate gas limit and gas price, but you can specify them manually:
    // gasLimit: ethers.utils.hexlify(gasLimit), // Optional
    // gasPrice: ethers.utils.hexlify(gasPrice), // Optional
  };

  // Sign the transaction
  const signedTx = await wallet.signTransaction(tx);

  // Send the signed transaction
  console.log("Sending signed transaction...");
  const txResponse = await provider.sendTransaction(signedTx);
  console.log(`Transaction hash: ${txResponse.hash}`);

  // Wait for the transaction to be mined
  const receipt = await txResponse.wait();
  console.log(`Transaction was mined in block ${receipt.blockNumber}`);
}

main().catch(console.error);

This could be done in other ways as well, like with GO which is stated here