Integration with EDI

Electronic Data Interchange (EDI) is a process where orders, invoices, and other business transactions are passed electronically between business systems. It requires a specialized system to manage this process, and the expertise to keep it going

Benefits Disadvantages
EDI is well established and has been used for over 40 years. EDI requires configuration at both ends, both parties must configure their systems to send messages to each other.
EDI typically doesn’t require software development, simply the mapping of data between certain fields and applying certain rules EDI transmissions do not receive real-time responses, so if a message fails, then a separate message will be sent in reply indicating the failure. The reason for failures can sometimes be less specific than API integration.
EDI implementations are typically faster than API integrations
Integration with APIs

An API (application programming interface) is a way to connect to systems with other systems or businesses. Essentially, they allow access with certain restrictions to a business system and information can be pushed and pulled from the system. For most businesses, an EDI implementation provides the same business benefit as an API implementation.

Benefits Disadvantages
Typically more flexible than an EDI integration. APIs typically expose a lot of data within the system that can be easily searched, e.g. customer names, addresses, product names, SKUs, imagery, pricing, etc. Every API provided by every system is different and requires software development to be performed. Code must be written for the specific API and thoroughly tested. APIs typically apply rate limits and paging which must be accounted for.
Real-Time - Integration with APIs is real time. The response is immediate and represents the data within the system at that time. Systems must have an API available for use, not all systems expose a full API which can be used.
When an API is available and well documented, only the party connecting to the API is required to take action.
Well documented APIs mean less collaboration is required between all parties to have a business to business link.