I received a reply from HRV4 Training. Unfortunately they don’t have an API and push data to TP because a lot of people have asked for it. They don’t think this is a good idea however.
Thank you for your message and interest in HRV4Training. We do not have APIs, so coaches need to use our Pro platform to analyze the data. The only way you currently have to integrate the data is via the csv file that can be exported from Pro, but obviously that needs to be manually loaded into your platform.
We do consider custom integrations with other platforms when we have a large enough critical base from our users demanding it. As an example, we push data to TrainingPeaks, however, this does not really provide value (in my opinion) as it’s all decontextualized, not interpreted with respect to normal values, there is no analysis of the CV or other relevant parameters either (for long term trends for example). “pushing HRV” is in our opinion only harmful to the entire field as it does not help anyone making sense of the data (due to the reasons explained above), which is why Pro should be used (and indeed most people integrating our app with TP, then use Pro regardless).
All the best
Daniel