Technically the IRS will not start processing returns until 1/23 however they will pull some (not all) of the millions of returns that are sitting on POOLING servers accross all the income tax companies participating in the efile process to test their efile system. HOWEVER even if you get pulled in an early test batch and actually get accepted for processing before the 23rd they will not actually start processing returns until the 23rd. Being in a test batch has it's own risks ... from time to time returns in early test batch have gotten stuck in the pipeline or even lost for months. I personally don't file any of my client's returns until the IRS system is up and running smoothly for at least a couple of days and my client's like my conservative approach. Of course we don't offer any of those riduculus advances or prices bank products and I am happier for it.
https://www.irs.gov/newsroom/irs-sets-january-23-as-official-start-to-2023-tax-filing-season-more-he...
