# 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: * Telegram: [Head of Business Development](https://t.me/Annie_LLLEEE) **You can pay service fees using the following tokens:** * **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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.apro.com/en/data-pull-evm-chain/on-chain-costs.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.