Webservice (SOAP) API
The Webservice API is the most widely used API. It uses SOAP envelopes to pass information back and forth between you and Marketing Cloud. Often, a code library is used to convert C#/Java/PHP/other code to the SOAP envelope used by the Marketing Cloud. If you're working in one of these environments, it may come up that Support requests the SOAP envelope from you to troubleshoot issues.
Tip: Logging this SOAP Envelope varies by language.
The Webservice API should be used for:
- Subscribers and Lists
- Triggered Sends (may also use REST)
- Most other Email App Activities
Fuel (REST) API
The Fuel API, commonly referred to as REST API, uses JSON payloads and resource endpoints. All new Marketing Cloud technologies will use the Fuel API. Get started with REST API by visiting our help page on the topic.
The Fuel (REST) API should be used for:
- Journey Builder
- Mobile Connect
- Mobile Push
- Triggered Sends (may also use SOAP)
The Marketing Cloud can be utilized via the Fuel SDK (Not the same as the FUEL API). The Fuel SDK is a collection of code libraries that use both the SOAP and REST APIs together to interact with the Marketing Cloud.
More information on the Fuel SDKs:
The XML API is the Marketing Cloud's oldest API, and not very commonly used to date. It is NOT supported in the Enterprise 2.0 Editions of Marketing Cloud accounts. The Marketing Cloud presents the XML API information for existing implementations only. The XML API will receive no additional functionality, and new customers should use the SOAP API and REST API for future development.