On Friday, October 9, the developer behind Intervals.icu posted a short message on his own forum that has since turned into the biggest thing to hit Garmin's training community this year.
"Unfortunately Garmin terms and conditions have been updated and 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."
Intervals.icu is one of the most widely used training platforms in endurance sport. If it has to block Garmin data, a lot of people lose access to a lot of their own workouts.
Three days later, the first app died. Intervals Pro, an AI coaching service built entirely on top of Intervals.icu, has closed. Its own site says it plainly: "Garmin data will no longer be available through Intervals.icu, which the coach depends on, so coaching has stopped." Billing stopped with it, prepaid time is being refunded automatically, and conversations can be downloaded until October 19.
That is the shape of this story so far. Nothing has been finalized, Garmin has said nothing publicly, and one company has already shut down because of it.
What Garmin Actually Changed
The clause at the center of this is 5.1(o) of the Garmin Connect Developer Program Agreement. It prohibits a licensee from:
developing a Licensee application programming interface to provide End User Data to third-party websites, software applications, platforms, services, or products that have not been approved by Garmin in writing.
In plain terms, Garmin's partners can pull data out of Garmin Connect. What they cannot do is run their own API that hands that same data to somebody else without permission. Intervals.icu is exactly that kind of hub. Apps and coaching services read your activities and wellness data by going through Intervals.icu rather than through Garmin directly, and that is the chain the clause targets.
Here is the wrinkle, and it matters for how you read all of this. Forum members went looking for the actual change and could not find new wording. One long-time user checked the public PDFs: the text of 5.1(o) is identical in the October 2023 version and the March 2026 version. Another pointed out that a diff of the live terms against the older documents shows no difference either.
So the likely change is not new language. It is new enforcement of language that was already sitting there. Garmin is telling partners that a rule it never pushed on before now applies.
What Intervals.icu's Developer Says
David, who runs Intervals.icu, has been careful not to overstate things, and that caution is worth preserving.
On October 9 he confirmed he had "a good call with Garmin today about the updated terms and conditions" and that they were "continuing to discuss what this means for all athletes including those using the API for their own personal analysis and projects."
On October 12 he went further on scope, while flagging it as speculation rather than settled fact:
- Everything Garmin-sourced is probably in scope. Activities, wellness data, Fit files and streams.
- Historical data is likely affected too. "This will likely apply to historical data, anything that came in via the Garmin API." That is the part that is spooking people. This is not only about new workouts, it is about years of training history already sitting in Intervals.icu.
- Files you upload yourself look safe. A Garmin Fit file you export and upload manually "is likely ok," because it did not arrive through Garmin's partner API.
He also said nothing is final: "We are still talking to Garmin and nothing has been finalised yet."
The Second Front: Garmin Is Stripping Data From Fit Files
Separate from the terms change, something else has been happening since late September. Garmin has been filtering its own metrics out of the Fit files it sends to partners.
The community project garmin-intervals-bridge documents this in detail. Its description says Garmin "strips its own metrics from the Fit files it hands to partners," naming Stamina, Recovery Time, VO2 max, Performance Condition, Training Effect and Sweat Loss. The bridge works by pulling the original file from your own Garmin Connect account and filling the missing fields back in on the activity the official sync already created.
You can see the pattern here. Garmin's partner sync still delivers your workout. It just arrives with fewer of Garmin's own computed metrics attached. For anyone using a third-party platform to track training load or recovery, those are not cosmetic fields.
What This Means If You Own a Garmin Watch
The practical fallout depends on how your data moves.
If an app talks to Garmin Connect directly, it keeps working. The platform you sync to straight from Garmin, whether that is Strava, TrainingPeaks or anything else with its own Garmin connection, is not affected by this. The terms govern partners passing Garmin data onward, not partners receiving it.
If an app reads your data through Intervals.icu, it is exposed. That is the Intervals Pro case, and it will not be the only one. Multiple developers in the same thread said their apps are affected, including coaching platforms and analysis tools built on the Intervals API.
Your historical activities may go dark through the API. This is the worst-case scenario David described. Even if new uploads keep working, anything that arrived via the Garmin API could stop being visible to authorized third-party apps.
Manual uploads are the escape hatch. Export your Fit files from Garmin Connect yourself and upload them, or use a tool like the bridge that fetches the original file with your own login. David's read is that self-uploaded files sit outside the terms, because they were not delivered through Garmin's partner API.
Your watch keeps working normally. Nothing here changes how a Garmin Forerunner or a Garmin Fenix records a run. The fence is around what happens to the file afterward.
Why People Think This Is Happening
Garmin has not explained the change, so the community is connecting dots, and the dots are not hard to connect.
In July, Garmin bought TrainingPeaks and TrainHeroic, two of the biggest coaching platforms in endurance and strength training. In September, Garmin paused new applications to the Connect Developer Program and removed the signup form, with no reopening date and no notification list. And Garmin now sells AI-driven insights through Connect+, its subscription tier.
Put those together and you get a company that owns a major training platform, has closed the door to new partners, sells a subscription on top of your data, and is now telling existing partners to stop passing that data along. Whether that is a strategy or a coincidence, it reads as one from the outside. "I guess it's finally time to move over to Coros," one member wrote. Others went further: several said the news tipped their next watch or bike computer purchase away from Garmin entirely.
There is also a legal argument in the thread. EU users have data portability rights under the Data Act, which has applied since September 2025, and the argument goes that a contract term cannot take away a user's right to move data they generated. David's response to that was the right one: he is an engineer managing a platform, not a lawyer, and he is not going to build his business on a legal theory he cannot test.
The Bottom Line
Three weeks ago, Garmin's developer story was that new partners could not get in. Now the story is that existing partners may have to stop sharing the data they already receive, and that data may include your history going back years.
Intervals Pro is already gone. Garmin and Intervals.icu are still talking, and the outcome is not settled. But the direction is one-way: Garmin is pulling its training ecosystem tighter around itself, one layer at a time.
If you live in a coaching platform that sits behind another platform, this is the week to find out how your data actually reaches it. If the answer involves a Garmin API somewhere upstream, a manual Fit export is worth setting up now, before you need it.
Sources: the Intervals.icu forum API access thread (developer posts of October 9 and October 12, and community replies), the Garmin Connect Developer Program Agreement published on Garmin's developer portal (clause 5.1(o)), Intervals Pro's own closure notice at intervals.pro, the garmin-intervals-bridge project documentation covering Garmin's Fit file filtering, and our earlier coverage of the Connect Developer Program pause, the TrainingPeaks and TrainHeroic acquisition, and Connect+.
