# On-Chain Costs

Each time data is published on-chain via the **Data Pull** model, **gas fees** and **service fees** are required to be covered. To enhance the user experience, APRO may offer temporary discounts or promotions based on the gas fee dynamics of different blockchains.

**For more information on on-chain costs, please contact us via:**

* Email: <bd@apro.com>
* Telegram: [Head of Business Development](https://t.me/Annie_LLLEEE)

**You can pay service fees using the following tokens:**&#x20;

* **Native blockchain gas tokens** and their **ERC20-wrapped** versions.

**Cost Responsibility in Data Pull Models**

In most data pull-based models, including APRO's, it is typical for on-chain costs to be passed onto the end users when they request data during transactions. This ensures efficient and flexible cost management in decentralized applications.