Garmin’s new developer terms threaten the apps that read your watch data through Intervals.icu

Intervals.icu, the training-analysis website used by many cyclists, runners and triathletes, says it will probably have to stop sharing Garmin data with other apps after Garmin changed the terms it sets for software developers. One coaching service that relied on that data, Intervals Pro, closed on 12 October.

The change does not stop Garmin owners from syncing their watches to Intervals.icu itself. What is at risk is the next step: the many smaller apps, coaching tools and personal projects that read a Garmin user’s activities from Intervals.icu rather than from Garmin.

What Intervals.icu has said

The site’s developer, who posts on its forum as David, broke the news on 9 October. “Unfortunately Garmin terms and conditions have been updated,” he wrote, adding: “It is likely that we will have to block access to Garmin data via the API soon.” “We didn’t receive any announcement or notification, the new T&C’s popped up in the Garmin developer portal.”

He added that Intervals.icu “has had an open API for at least 5 years now and this will cause a great deal of harm for many coaching businesses, apps and individuals”. He said he had not found the new terms on the public internet and would not post them because Garmin might consider them confidential.

Later that day he reported “a good call with Garmin”. “We are continuing to discuss what this means for all athletes including those using the API for their own personal analysis and projects,” he wrote.

On 12 October he said nothing had been finalised, and that his answers to developers’ questions were speculation. Asked whether whole activities, FIT files, data streams and wellness data would be affected, he replied: “Probably all of those.” Asked about activities already stored, he wrote: “This will likely apply to historical data, anything that came in via the Garmin API.”

The first closure

Intervals Pro, an AI coaching service built on top of Intervals.icu, has stopped. “Garmin data will no longer be available through Intervals.icu, which the coach depends on, so coaching has stopped,” its closure notice says. Billing has ended, unused prepaid time is being refunded automatically, and users can download their coaching conversations from the app’s settings until 19 October 2026.

The service’s owner, Max Revitt, was quoted by the5krunner as saying: “Intervals.pro is closing because Garmin are going to restrict downstream data, just as Strava have done.” The5krunner reported that the service had 3,600 athletes. Unbroken Review has not been able to confirm that figure independently.

What is and is not affected

Much remains unclear, including when any block would begin. “I don’t have any info on that. But at the very least Intervals.icu would need time to implement changes,” the developer wrote on 12 October.

Based on his forum posts so far:

• Data from other brands (he named Suunto, COROS, Polar and Oura) would remain available to connected apps under those companies’ own terms.
• FIT files an athlete uploads themselves are “likely ok”, he wrote on 9 October. On 12 October he added: “As far as I understand things, this only applies to data received from the Garmin API.”
• Personal use is not settled. Whether athletes’ own API keys, used to link Intervals.icu to spreadsheets, scripts or AI assistants, will be treated differently is part of the talks with Garmin.

According to the5krunner, Garmin has not commented. A forum user pointed to a clause in Garmin’s publicly available developer agreement that bars licensees from passing user data to third-party services Garmin has not approved in writing. Garmin has not said whether that clause, or something in the newer terms, is the basis for the change.

Why it matters

Training data has become a contested asset. Strava tightened the rules for apps that use its data in November 2024, as the5krunner noted, and Intervals Pro’s owner explicitly compared the two moves. Garmin now owns TrainingPeaks, one of Intervals.icu’s best-known rivals, although nothing published so far links that purchase to the new terms.

For now, a Garmin owner who uses Intervals.icu on its own should see no difference. Anyone who relies on a separate app that reads their Garmin history from Intervals.icu should check with that app’s developer, and keep their own copy of their activity files. Garmin had not published any statement on the change by 14 October.