Mapping product ids ideally based on a common number
Currency - Either use currency symbols or ideally unique three letter-codes (EUR, USD, …)
Discounts - ideally in both systems as a percentage or integer number, being a percentage; mixed spellings need a mapping table (Env Variables)
Tax rates - ideally in both systems as a percentage or integer number, being a percentage; mixed spellings need a mapping table (Env Variables)
3. Advertising systems
(e.g. Facebook, Google Ads, ... )
Classical object hierarchy: Advertisers > Campaigns > Line Items > Creatives - Ideally systems have external_id fields in order to store your internal IDs there for later reference.
Audiences - Usually IDFA, AAID, cookies, or similar internal identifier
Considerations for real-time sync vs. daily (scheduled)
For real-time syncs, either webhooks (Webhook Helper or Webhook Trigger for Connector) need to be available on both systems, informing the other system that something changed, or a scheduler needs to be run every five minutes and be able to only check for recently updated records, and no one should have worked in the other system in parallel.
If the before mentioned options are not available, e.g., due to an old system that doesn’t have updated timestamps nor webhooks, a leading system should be determined and ideally, synchronizations should happen less frequently e.g. daily and scheduled (using the Schedule Helper), and all data entry and updates should be done in the leading system.