How often should I query the REST API?


For a specific CSDL query how often do you recommend to do a
request to to get interactions? …1 each
15 seconds? 10 per minute?..


At the most, you should hit this endpoint each 10 seconds. This is explained in our Buffering documentation. Please be aware, that for high throughput streams (for example, a stream that produces more than 200 interactions in 10 seconds), interactions may be lost as the buffer will only hold the latest 200 interactions. You may want to consider using the Streaming API instead.