# Buy on Rest API

#### Information about two methods of purchasing energy using Tronsave's API key and a signed transaction:

### [**Using Signed Transaction**](https://docs.tronsave.io/developer/rest-api-v0/buy-on-rest-api/use-signed-transaction)

* In this method, users create a transaction and sign it with their private key.
* The signed transaction is then sent to the blockchain network for validation and execution. This ensures that only the owner of the private key can perform the transaction.

**Advantages**:

* A high level of security is required when signing with a private key.
* More control over payment funds, as customers manage them directly.

**Disadvantages**:

* Transactions sent to the blockchain network will incur additional transaction fees.
* More complex integration requires an understanding of transaction signing and validation processes.

### [**Using API Key**](https://docs.tronsave.io/developer/rest-api-v0/buy-on-rest-api/use-api-key)

* To use the API key, you need to create a Tronsave internal account and deposit funds into it. \[[Read the full guide here](https://docs.tronsave.io/developer/get-api-key)]
* After creating the internal account, an API key will be generated, which will be used to authenticate your transactions.

**Advantages**:

* Fast and secure transactions.
* Easy integration.
* Save Transaction Fees

**Disadvantages**:

* Funds need to be deposited into the internal account to execute transactions.
* The customer's internal account will be managed by the Tronsave system.