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The data available from the Course Discovery API will include text (course name and description), media (intro video and instructor portraits), and pricing. The authoritative form of this data is owned by several different services right now, including (for edx.org) StudioLMS, the Drupal marketing site, Programs, and Otto (the ecommerce service). This data ownership is sensible, but in order to provide a performant API for Course Discovery, and to isolate the internal and external APIs from each other, it will be de-normalized and cached by the Course Discovery service. To provide low latency availability for the cached data, the primary data sources will push notifications about data changes to the Course Discovery service via a new Inter-IDA Messaging system, and the Course Discovery Service will call back to those applications to fetch the full data contents.
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