Trio

Trio is an open-source automated insulin delivery (AID) system that runs entirely on an iPhone — there is no Android version.¹ It is built on the OpenAPS algorithm (the "oref" decision-making engine first developed for the original DIY rigs), adapted for iOS.¹ Its lineage runs from Ivan Valkou's FreeAPS X, through the community project later known as iAPS, to Trio, reusing the LoopKit toolkit and a broad set of community-maintained pump and CGM drivers.² When development of iAPS diverged over questions of open-source governance and peer review, the community split off Trio as a separate project, which has become the recommended landing spot for people migrating off iAPS to an oref-based loop on iPhone.³

Algorithm. Like its OpenAPS roots, Trio predicts glucose and micro-doses insulin every few minutes. It offers super-micro-boluses (SMB), automatic sensitivity adjustment, dynamic insulin sensitivity (Dynamic ISF), and unannounced-meal detection — so it can blunt a rise even when you forget to enter carbs.³ In April 2026 the team shipped v0.7.0, described as the first fully stable release of a completely rewritten app, with the whole logic and data layer rebuilt for speed and stability.⁴

Hardware. Supported pumps include Omnipod DASH and Eros pods, the Dana RS and Dana-i, Medtrum Nano patch pumps, and Medtronic pumps.⁴⁵ Since mid-2026 both pod types are driven by a single unified driver, OmnipodKit: it was introduced as an option in v0.8.1 and became the only Omnipod driver in v0.8.2 (15 June 2026), which removed the legacy OmniBLE/OmniKit code.⁶ Omnipod 5 is a different picture. It is not supported in any released version of Trio, but it is no longer simply off the table: the community's Omnipod-5 project has an open beta — announced at D-Data 2026 — that requires building a feature branch yourself and is aimed at experienced users, with general availability targeted for late summer 2026 and the project itself hedging that to "when it's ready".⁷ Supported glucose sources include Dexcom G5, G6/ONE and G7/ONE+, Libre (limited models), Medtronic Enlite, and Nightscout or xDrip feeds.⁵ It also includes a rewritten Apple Watch app and Live Activities, plus caregiver/remote features.⁴

Customizability and community. Because it is fully open source, every setting and the algorithm itself are inspectable and tunable.¹ It has its own documentation site and active community support, and is backed by the Nightscout Foundation organization.⁸

Setup and legal status. You build the app yourself — either a "browser build" using GitHub, or a Mac build using Xcode.⁵ A free Apple Developer account requires rebuilding the app every 7 days.⁵ Critically, Trio "has not been evaluated by any regulatory agency and is not approved by any healthcare authority. You build and run Trio at your own risk."¹

Clinical evidence. Trio itself has not been studied in a randomized trial, but it implements the same OpenAPS algorithm tested in the landmark CREATE trial. According to PubMed, that multicenter randomized controlled trial in 97 children and adults found open-source AID raised time-in-range from 61% to 71% over 24 weeks — about 3 hours 21 minutes more per day in range than a sensor-augmented pump — with no severe hypoglycemia or ketoacidosis.⁹ A 24-week continuation phase (extending total use to about 48 weeks) confirmed sustained benefit across different pumps and ages with no new safety concerns,¹⁰ and a qualitative sub-study reported empowerment and improved wellbeing among Indigenous Māori users.¹¹ This is the strongest evidence base any open-source loop can point to, though it tested an AndroidAPS/OpenAPS build, not Trio specifically.⁹

What's coming. Development is rapid, and the summer of 2026 shows both the upside and the cost of that pace. v0.8.2 (15 June 2026) finished the Omnipod driver migration and added temp-target display in the Live Activity plus Apple Watch connectivity fixes.⁶ Five days later v0.8.3 (20 June 2026) shipped as a hotfix for a regression introduced in v0.8.1 and carried into v0.8.2: a mismatch between the basal delivery limits stored in OmnipodKit and those set in Trio made loop cycles fail with an "Invalid Settings" error, which stopped some pods looping altogether — the release notes told Omnipod users to update immediately.⁶ That is the DIY bargain in one release: fast iteration, and you are the one who has to keep up. The current version, v0.8.4 (2 July 2026), is a smaller patch pulling in upstream driver fixes — Medtrum bolus and Bluetooth reliability, better handling of Omnipod fault states, and a Dexcom G7 sensor-expiry warning that now fires in the final 48 hours rather than the final 24.⁶ Beyond the Omnipod 5 beta, one outlet reported from ADA 2026 that Tandem Mobi support is in testing with a year-end target; the project has not confirmed that itself, so treat it as reported rather than promised.¹² All of this points toward continued work on responsiveness, caregiver tooling, and onboarding ahead of a future 1.0 milestone.⁴

References

1. Trio open-source community. TrioDocs (2026). https://triodocs.org/ ↩ ↩² ↩³ ↩⁴

2. Trio open-source community. Trio README (FreeAPS X / iAPS / LoopKit lineage). GitHub: nightscout/Trio (2025). https://github.com/nightscout/Trio ↩

3. Diabetech. What Is Trio? The Open-Source AID System Explained & What's Next. Diabetech (2024). https://www.diabetech.info/p/what-is-trio-the-open-source-automated-insulin-delivery-system-explained-what-s-next ↩ ↩²

4. Trio open-source community. Trio Releases (v0.7.0 first stable rewrite, Apr 15 2026; v0.8.x features). GitHub: nightscout/Trio (2026). https://github.com/nightscout/Trio/releases/tag/v0.7.0 ↩ ↩² ↩³ ↩⁴

5. Trio open-source community. Trio FAQ — supported pumps, CGMs, browser/Mac build, Apple Developer account. TrioDocs (2026). https://triodocs.org/help/faq/ ↩ ↩² ↩³ ↩⁴

6. Trio open-source community. Trio releases — v0.8.2 (15 Jun 2026, OmnipodKit migration completed), v0.8.3 (20 Jun 2026, Omnipod delivery-limit hotfix), v0.8.4 (2 Jul 2026, driver fixes and 48-hour G7 expiry warning). GitHub: nightscout/Trio (2026). https://github.com/nightscout/Trio/releases ↩ ↩² ↩³ ↩⁴

7. Nightscout / Trio & Loop communities. Omnipod 5 — Open-Source AID (open beta, feature-branch build). (updated 2 July 2026). https://nightscout.github.io/omnipod-five/ ↩

8. Trio open-source community. TrioDocs — documentation and community support. (2026). https://triodocs.org/ ↩

9. Burnside MJ, Lewis DM, Crocket HR, et al. Open-Source Automated Insulin Delivery in Type 1 Diabetes (CREATE trial). N Engl J Med 387(10):869-881 (2022). According to PubMed; https://doi.org/10.1056/NEJMoa2203913 ↩ ↩²

10. Burnside MJ, Lewis DM, Crocket HR, et al. Extended Use of an Open-Source Automated Insulin Delivery System: 24-Week Continuation Phase Following the CREATE RCT. Diabetes Technol Ther 25(4):250-259 (2023). According to PubMed; https://doi.org/10.1089/dia.2022.0484 ↩

11. Burnside M, Haitana T, Crocket H, et al. Interviews with Indigenous Māori with type 1 diabetes using open-source AID in the CREATE randomised trial. J Diabetes Metab Disord 22(1):861-871 (2023). According to PubMed; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10035484/ (https://doi.org/10.1007/s40200-023-01215-3) ↩

12. Diabetotech. Closed-Loop Updates from ADA 2026. Diabetotech (18 June 2026). https://www.diabetotech.com/blog/closed-loop-updates-from-ada-2026 ↩