I don't have much experience using the ACS and have been googling forums to get the most comprehensive ZCTA-Year ACS dataset possible. I tried using IPUMS, but cannot seem to find the option to download data at the ZCTA level, even when only using the 5-year ACS sample. I thought that it's likely that somebody wanted to get a similar dataset before on here. If yes, could you point me to what ACS resource I should use? The API?
IPUMS has multiple websites that provide ACS data. IPUMS USA provides only microdata (individual and household level data), which have very limited geographic information in order to protect respondent privacy. It's not possible to identify ZCTAs in microdata. IPUMS NHGIS provides geographic summary data (data for geographic areas), which includes comprehensive ACS 5-year data for ZCTAs and many other levels of geography. If you're unable to find and download ZCTA data through IPUMS NHGIS, please let me know.