# Posting on the Blockchain

Once the transactions are organized and secured through the sequencer and Merkle Tree, the next step is to post them on the blockchain for transparency and verification. At the same time, the system groups these transactions into **epochs**, which are time-based windows for processing transactions.

<figure><img src="https://651401021-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FY2TowO8fF4a1GlgpRfIZ%2Fuploads%2FjOfqrwn8KmqaBZFRwCfc%2Fimage.png?alt=media&#x26;token=98c607c7-2393-4dd9-a738-b99264e48511" alt=""><figcaption><p>Posting on the Blockchain</p></figcaption></figure>

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In the **decentralized method** (Submission B), orders are posted directly on the blockchain.&#x20;
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Orders that went through the sequencer (Submission A) also end up on the blockchain once they are fully processed by the sequencer.
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### **Posting on the Blockchain**:

1. Transactions secured with the **Merkle Tree Root** are collected and grouped into **epochs**, which are blocks of time (10 seconds long). All the transactions made within that time period are added together and processed as one group.
2. Think of an epoch like a time bucket (every 10 seconds), where the blockchain collects all the transactions during that time and puts them into one block. This helps the system handle lots of transactions efficiently while keeping everything organized.
3. Once the transactions are bundled, they are posted on the blockchain. This step makes the entire batch of transactions visible to everyone, ensuring full transparency.
4. Because the blockchain is decentralized, [**Node Validators**](https://docs.yamata.io/yamata-nodes/order-validation/what-are-validating-nodes-vns) can check transactions without relying on a central authority. They ensure that transactions match the user submission order, verify that they are processed in the correct order, and compare on-chain (Submission B) data with the off-chain (Submission A) data received from the sequencer. This means Node Validators check if the off-chain (sequencer-processed) and on-chain versions of the transaction are aligned, guaranteeing the integrity of the system, and confirming that all transactions are fairly handled and visible to everyone.