Hi @akwankl
ACS has API for injecting data however there is a huge gap between AEP and ACS when it comes to supported volume.
If you look at the Campaign Standard Product Description page, section Engine Call, you will see that ACS API supported volume is tiny (from 2 / s to 10 / s depending of your license).
For that reason, we strongly suggest to use the AEP - ACS connector as mentioned earlier....
if you still choose the ACS API route, you will have to design a strong solution to slow down the API calls to ACS from AEP, as such you would build a middle layer to throttle the calls in ACS to respect the supported volume..... This has been done in the past using solution such as Kafka or Azure where you would throttle the ingestion.
Also, if you choose the API route, I will strongly suggest that you ingest data in ACS via API only for critical information, FOr instance, you could inject via API information capture during registration and account update including consent, then using the AEP-ACS connector, you will ingest all data (including the one ingested by API) as per the connector (flat files)... You would use in all cases the ACS destination to push segment into ACS, so you might not need more data than the one acquired during registration and account update...
Hope this helps,
Thanks
Denis