Let's try to understand why the network needs to be synchronized. We currently have a decentralized blockchain network that consists of five nodes. The data across these nodes is not consistent; data on each node might vary, which would lead to the failure of the purpose of having a blockchain. Let's try to understand this situation with the help of an example. Go to Postman and send a sample transaction, as shown in the following screenshot:
![](https://static.packt-cdn.com/products/9781789618822/graphics/assets/95e23e83-399c-4276-8668-a3db6e116ee3.png)
Send this transaction to the node that's hosted on localhost:3001 by clicking on the Send button. This transaction will appear in the pendingTransactions array of localhost:3001/blockchain, which you can observe in the following screenshot:
![](https://static.packt-cdn.com/products/9781789618822/graphics/assets/b5479e71-514c-4ebf-b15e-858d0f704ec1.png)
Now, go to any of the other nodes and check for the transactions that were sent. We won't be able to view the transactions in the...