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How often fitness API documentation changes under us

History read through Nov 5, 2026 (main at 8fb512e) · 982 rows in the dataset · every figure recomputed from it at each build

From Oct 17, 2026 to Nov 5, 2026, this site's evidence files held 7,984 quoted rows from 139 source hosts. Its commit messages record 28 source changes (counted once per host per commit) on 21 hosts, which replaced 635 rows. Of the rows written by Oct 22, 2026, 10% had their source change within 14 days. The two largest changes, on developer.garmin.com and cloud.ouraring.com, account for 421 of the 635 replaced rows.

  • 28

    source changes under this site's quotes, counted once per host per commit, on 21 hosts

  • 635 of 7,984

    evidence rows replaced because their source changed

  • 10%

    of evidence rows written by Oct 22, 2026 had their source change within 14 days

  • 5 days

    median age of an evidence row when its source changed

Method

Pages on this site that are written from vendor sources keep an evidence file: one row per fact, with the claim, the source URL and a verbatim quote. A weekly workflow re-reads every URL and fails when a quote is no longer on its page, and a person then re-reads the source and fixes the page.

This study replays the git history of those files, 20 commits from Oct 17, 2026 to Nov 5, 2026, and follows every row from the commit that wrote it to the commit after which its file no longer held it. A row ends one of five ways: its quote changed, its URL changed, both changed, its claim was reworded over the same quote, or it was removed.

Why a row ended comes only from the message of the commit that ended it. Each explanation is a sentence copied from that message, and the generator fails if the sentence is not there or if a commit that mentions source drift has none. Source changed means the message says the vendor's page changed. Our change means this site changed the quote or URL while the source stood still. Unreachable means the page stopped answering. Where the message also says whether a fact or only the wording moved, that is recorded; otherwise the kind is left blank.

A source change is counted once per host per commit, so one vendor redesign that touched 300 rows counts once, and the row counts are given beside it.

Source changes by commit

676 of the 7,984 rows ended in the period: 635 because their source changed, 23 because this site changed a quote or URL, 16 because a source stopped answering, and 2 for a reason the commit message does not give. The other 7,308 were still in place at the end of the history.

Each bar is one commit that recorded source changes, dated by its merge; its length is the number of hosts the commit names.

Hosts with a recorded source change, per commitOct 22, 2026 (2979aee): 1 host, 300 rowsOct 22, 2026 (2979aee)1 host, 300 rowsOct 23, 2026 (fad6ea2): 7 hosts, 30 rowsOct 23, 2026 (fad6ea2)7 hosts, 30 rowsOct 28, 2026 (560d0d2): 7 hosts, 119 rowsOct 28, 2026 (560d0d2)7 hosts, 119 rowsOct 31, 2026 (af070f5): 1 host, 121 rowsOct 31, 2026 (af070f5)1 host, 121 rowsNov 2, 2026 (b92bce2): 5 hosts, 24 rowsNov 2, 2026 (b92bce2)5 hosts, 24 rowsNov 5, 2026 (177ebfb): 6 hosts, 36 rowsNov 5, 2026 (177ebfb)6 hosts, 36 rowsNov 5, 2026 (36be64d): 1 host, 5 rowsNov 5, 2026 (36be64d)1 host, 5 rows
Source changes per commit
DateCommitHostsRows replaced
Oct 22, 20262979aee1300
Oct 23, 2026fad6ea2730
Oct 28, 2026560d0d27119
Oct 31, 2026af070f51121
Nov 2, 2026b92bce2524
Nov 5, 2026177ebfb636
Nov 5, 202636be64d15

Hosts whose sources changed

The 21 hosts with at least one source change, by number of changes, with how many of their evidence rows were written in the period and how many were replaced.

Hosts with source changes
HostSource changesRows replacedRows written
developer.garmin.com2304559
docs.tryterra.co221260
raw.githubusercontent.com/the-momentum21638
sahha.ai216166
www.thryve.health29117
raw.githubusercontent.com/tryterra2418
support.coros.com2485
cloud.ouraring.com1121328
tryterra.co164270
openwearables.io140131
developers.google.com1982
raw.githubusercontent.com/sency-ai17104
docs.thryve.health1574
developer.withings.com14146
raw.githubusercontent.com/ultralytics1366
docs.wodify.com1250
www.cliniko.com1211
ringconn.com113
tryrook.io11190
validic.com1139
www.ultrahuman.com112

Fact or wording

Where the commit message says what kind of change it was, 20 of the 28 source changes were changes of fact, 4 were wording only and 1 were both; 3 do not say.

Every recorded source change
DateCommitHostKindRows
Oct 22, 20262979aeedeveloper.garmin.comfact300
Oct 23, 2026fad6ea2developer.withings.comfact4
Oct 23, 2026fad6ea2raw.githubusercontent.com/sency-aifact7
Oct 23, 2026fad6ea2raw.githubusercontent.com/tryterrafact2
Oct 23, 2026fad6ea2ringconn.comfact1
Oct 23, 2026fad6ea2sahha.aifact11
Oct 23, 2026fad6ea2support.coros.comfact2
Oct 23, 2026fad6ea2www.thryve.healthfact3
Oct 28, 2026560d0d2openwearables.iofact40
Oct 28, 2026560d0d2raw.githubusercontent.com/the-momentumfact1
Oct 28, 2026560d0d2raw.githubusercontent.com/tryterrafact2
Oct 28, 2026560d0d2sahha.aifact5
Oct 28, 2026560d0d2tryterra.cowording64
Oct 28, 2026560d0d2validic.comfact1
Oct 28, 2026560d0d2www.thryve.healthnot stated6
Oct 31, 2026af070f5cloud.ouraring.comnot stated121
Nov 2, 2026b92bce2docs.thryve.healthfact5
Nov 2, 2026b92bce2docs.wodify.comfact2
Nov 2, 2026b92bce2raw.githubusercontent.com/the-momentumfact15
Nov 2, 2026b92bce2tryrook.ionot stated1
Nov 2, 2026b92bce2www.ultrahuman.comwording1
Nov 5, 2026177ebfbdeveloper.garmin.comwording4
Nov 5, 2026177ebfbdevelopers.google.commixed9
Nov 5, 2026177ebfbdocs.tryterra.cofact16
Nov 5, 202636be64ddocs.tryterra.cofact5
Nov 5, 2026177ebfbraw.githubusercontent.com/ultralyticswording3
Nov 5, 2026177ebfbsupport.coros.comfact2
Nov 5, 2026177ebfbwww.cliniko.comfact2

What this method cannot see

  • It sees only committed changes. A page that changed and changed back between two reads, a page no evidence row quotes, and a change the quote check did not catch are all invisible here.
  • Dates are merge dates on main. A row written in a branch days before it merged carries the merge date, which makes rows look younger than they are.
  • The history is short: 20 commits over Oct 17, 2026 to Nov 5, 2026. The 14-day share counts only rows written at least 14 days before the end of the history, so rows written later do not dilute it.
  • Kind of change is recorded only where the commit message states it: 3 of the 28 source changes have no stated kind.
  • One large change weighs heavily on the row figures: the two largest account for 421 of the 635 replaced rows, which is why the count of source changes is given beside them.

Download the data

The rows behind every figure on this page, CC BY 4.0: fitness-api-docs-drift-2026.json, fitness-api-docs-drift-2026.csv and the dataset card that describes every column. All of this site’s datasets are on the open datasets page.

How to cite

Quote a figure with the date its data was read and link this page; each headline figure has its own anchor, such as https://aifitnessapi.com/research/docs-drift#drift-events.

AIFitnessAPI. "How often fitness API documentation changes under us." Data as of 2026-11-05. https://aifitnessapi.com/research/docs-drift
@misc{aifitnessapi-research-docs-drift,
  author = {{AIFitnessAPI}},
  title = {How often fitness API documentation changes under us},
  year = {2026},
  url = {https://aifitnessapi.com/research/docs-drift},
  urldate = {2026-11-05},
  note = {Data as of 2026-11-05}
}

More citable counts about this site and the ecosystem it tracks are on the press page.

Frequently asked questions

How was documentation drift measured on this site?

By replaying the git history of the site's evidence files: 7,984 quoted source rows across 20 commits, each followed to the commit that replaced or removed it. Why it ended is taken only from that commit's message, as a sentence copied from it.

Does a changed quote mean the vendor changed a fact?

Not always. Of the 28 source changes, the commit messages call 20 changes of fact, 4 wording only and 1 a mix of both, and do not say for 3.

Which documentation hosts changed most often?

developer.garmin.com, docs.tryterra.co, raw.githubusercontent.com/the-momentum, sahha.ai, www.thryve.health, raw.githubusercontent.com/tryterra and support.coros.com, with 2 source changes each in the period. By rows, the largest were developer.garmin.com (300 rows on Oct 22, 2026) and cloud.ouraring.com (121 rows on Oct 31, 2026).

Were some quotes changed by this site rather than by the vendor?

Yes: 23 rows ended because this site changed the quote or URL (for example pinning a locale or lengthening a short quote), 16 rows because a source stopped answering, and 2 rows without a stated reason. None of these count as drift.

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