Custom query

Retrieve arbitrary values

A custom query, unlike Balance query, is a feature that allows you to retrieve arbitrary data and emit it as an event. Essentially, you can send a query in a similar manner to a balance query, but the input fields are different.

1. Input the content of the query

To submit a query, you need to specify the choice of chain, the target contract address, the block height, and the storage slot.

You can use tools like solc or foundry to determine storage slots. The mapping of storage slots in Solidity is documented in the official Solidity documentation.

Additionally, for clearer explanations, you can refer to the documentation provided by Axiom.

If you don't have data to query, you can use the following sample data to execute the query. (You can query the Sepolia USDC held by 0x1aaaeb006AC4DE12C4630BB44ED00A764f37bef8)

Chain	Block height	Contract address	Slot
Sepolia	5407197	0x91D1a12c16d2Ff1c072069a9d9c90d2c0299B244	0xf8a7b40e9f08589bcdc65a6dd287fc853d1877d75bf7422ff09c0651dea732a4

2. Submit the queries

Like the balance query, you will need MATIC to send the transaction since it involves sending a transaction.

3. Wait for the query results

You can check the status of the query in the Explorer.

4. Completion of the response transaction

Once the response transaction is completed, you can view the actual transaction from the transaction hash, and you will be able to verify the data queried in the event section.

Here is an example of a transaction: https://mumbai.polygonscan.com/tx/0x749c8a652131fdc665928d86eb3f8a16d4f1db01bb007c82d1ffb978f42ad688#eventlog