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; Omnipod 5 is not supported.⁴⁵ 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.⁶

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.⁷ 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,⁸ and a qualitative sub-study reported empowerment and improved wellbeing among Indigenous Māori users.⁹ This is the strongest evidence base any open-source loop can point to, though it tested an AndroidAPS/OpenAPS build, not Trio specifically.⁷

What's coming. Development is rapid: releases through v0.8.x (May 2026) added a unified Omnipod manager for both pod types, anonymous opt-out telemetry, therapy-settings upload to Tidepool, and refined glucose smoothing — signposting 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. TrioDocs — documentation and community support. (2026). https://triodocs.org/ ↩

7. 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

8. 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 ↩

9. 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) ↩