# Dapp Notifications

Sending.Network (SDN) provides a universal inbox to receive messages from dapps and wallets. This way, users can receive time-sensitive dapp messages, like an NFT floor price drop or an imminent liquidation in a lending protocol position. There would be tremendous user scenarios for such communication. A decentralized exchange can notify users when the desired gas price is reached, or an NFT marketplace sends out heads-up notifications of NFT auctions, saving users’ effort from regularly checking.

<figure><img src="https://2753396368-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1hPSqZauZ9JZ15UAJezj%2Fuploads%2FYT8BDHMKFgkG1mXw5Qtj%2Fnotification.png?alt=media&#x26;token=cb59a0fb-2279-4e47-9298-3e181f214cc7" alt=""><figcaption><p>Overview</p></figcaption></figure>

Below we provide a specific use case describing how the user can receive a decentralized exchange (DEX) notification inside the wallet app when the desired gas price is reached.

### **Use Case Name**

Receiving DEX gas price notification from wallet

### **Actors**

1. DEX
2. Wallet app
3. User
4. Sending.Network protocol

### **Preconditions**

1. The DEX has integrated the Sending.Network protocol.
2. The wallet app has integrated the Sending.Network protocol.

### **Basic Flow of Events**

1. The use case begins when a user authenticates in the DEX.
2. The user sets a target gas price as a notification condition.
3. When the gas price is met, DEX calls Sending.Network service message interface to send out a notification message to the user's wallet address.
4. The wallet receives the DEX message.
5. The wallet displays the message.
6. The use case ends successfully.

<figure><img src="https://2753396368-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1hPSqZauZ9JZ15UAJezj%2Fuploads%2Fog9DhvrKJarJwLjp6U6C%2Fnotification%20diagram.drawio.png?alt=media&#x26;token=366b874f-83e2-4c80-b1b0-c652bf3464c3" alt=""><figcaption><p>Flow Chart</p></figcaption></figure>

### **Post-conditions**

The user successfully receives the DEX gas price notification and the message has been saved in the wallet app.