Fast and cost effective way to fetch historical ERC20 token balances for multiple wallets

If you’re a dev doing on-chain wallet analysis: I wrote a guide on bulk fetching token balances for multiple wallets and across different time periods.

When I first started working with Ethereum data I found it surprisingly difficult to figure out how to do this - especially in a way that was cost effective (didn’t burn through all my API credits).

It honestly took me forever to find the best method. So I decided I wanted to write a guide about it.

So here it is: https://medium.com/@martinvkirov/the-best-method-for-bulk-fetching-erc20-token-balances-35b862f33eec