Interoperability with Automated Insulin Delivery (AID)

Interoperability with Automated Insulin Delivery (AID) Systems

Interoperability is what lets a continuous glucose monitor (CGM) made by one company send its readings to an insulin pump and dosing software made by others. In the US, the FDA makes that possible by reviewing the three parts of an automated insulin delivery (AID) system separately: the sensor, the pump and the algorithm [1][2][3]. The clearest sign of how far this has gone came in December 2025. Medtronic's MiniMed 670G had been approved in 2016 as a bundle with Medtronic's own Guardian Sensor (3) [4]; nine years later, the business now called MiniMed began selling its 780G system in the US with the Instinct sensor, made by Abbott [5].

Three parts, three FDA categories

Each piece of an AID system now has its own regulation, and each started with a single device.

• Integrated CGM (iCGM): a sensor "designed to reliably and securely transmit glucose measurement data to digitally connected devices, including automated insulin dosing systems" [1]. The first was the Dexcom G6, authorized in March 2018 through the De Novo pathway, the FDA's route for new kinds of low- to moderate-risk devices [6]. Dexcom stopped manufacturing the G6 after July 1, 2026, and points users to its G7 sensors [7].
• Alternate controller enabled (ACE) pump: an insulin pump built to receive, carry out and confirm delivery commands from an outside controller [2]. Tandem's t:slim X2 was the first, in February 2019 [8].
• Interoperable automated glycemic controller (iAGC): the software that calculates doses from glucose and other inputs, then commands a connected pump [3]. Tandem's Control-IQ technology was the first, in December 2019 [9].

Here's what surprised us about the history. Before these categories existed, the pump, sensor, transmitter and algorithm were approved together as one system; the MiniMed 670G's September 2016 approval covered its Guardian Link (3) transmitter and Guardian Sensor (3) along with the pump [4]. With the parts split apart, a new sensor or algorithm can be cleared on its own and paired with devices already on the market. As of October 2026, the FDA's database lists iAGC clearances for algorithms from eight companies. Tandem, Insulet, Beta Bionics and Tidepool are among them, and so is MiniMed, whose SmartGuard technology was cleared under that product code in August 2025 [10].

How the data moves between devices

The regulations read almost like a wiring diagram, and they were the plainest description of the data flow we found. An iCGM must deliver real-time readings "at clinically meaningful time intervals" and must not leave clinically significant gaps during its wear period [1]. The algorithm and the pump then pass delivery commands back and forth, and each command has to be sent, received, carried out and confirmed [3][2].

The ACE pump rule is the most specific. Its interface must provide secure pairing with outside devices and reliable data transmission. It must also share the pump's state with the controller, such as battery level, reservoir level and error conditions [2]. If the pump receives data outside the expected bounds, it has to keep operating safely. If the connection drops, it must keep therapy safe, for example by going back to a pre-programmed delivery rate, and it must keep a record of critical events so the exchange can be audited later [2].

Where the dosing software runs differs by system. Tidepool Loop is a mobile app [11]. With Omnipod 5, a Dexcom G7 or G6 setup can be managed from a compatible phone or the provided Controller, while the Pod and a FreeStyle Libre 2 Plus sensor are managed through the Omnipod 5 App on the Controller [12]. Abbott's compatibility page describes Omnipod 5's SmartAdjust technology as predicting glucose 60 minutes into the future [13]. For a closer look at how these controllers decide, see our article on AID algorithms.

Which sensors work with which systems (October 2026)

This table lists what each AID maker's own pages showed when we checked in October 2026.

Abbott's own page agrees on its side of the pairing: the FreeStyle Libre 3 Plus sensor connects with Omnipod 5, the t:slim X2, the iLet and twiist [13]. One practical difference shows up on the 780G. Its Guardian 4 and Simplera Sync sensors can be used without the MiniMed Mobile app, but pairing the pump with an Instinct sensor requires the app [17].

Switching sensors means a new prescription

Interoperability doesn't make sensors interchangeable at the pharmacy counter. Abbott discontinued its FreeStyle Libre 2 and Libre 3 sensors, which were available through September 30, 2025, in favor of the Libre 2 Plus and Libre 3 Plus, and patients moving to the Plus sensors need a new prescription [18]. Dexcom likewise tells G6 users to get a new prescription for the G7 or G7 15 Day; it says G6 supplies may remain for a time after July 1, 2026, but it can't guarantee them [7]. Insulet says Omnipod 5 will support the G6 for as long as the sensor remains available [12]. Which system and sensor suit a particular person is a decision to make with their care team.

Open-source and do-it-yourself systems

Some interoperable systems weren't built by device companies at all. A 2022 international consensus statement in The Lancet Diabetes & Endocrinology describes open-source AID systems, often called do-it-yourself systems, as co-created and supported by an online community of people directly affected by diabetes, with estimates at the time of several thousand active users worldwide [19]. The FDA has been wary of unreviewed setups. In May 2019 it warned patients and clinicians that unapproved or unauthorized diabetes devices, including automated insulin dosing systems, could lead to inaccurate glucose readings or unsafe insulin dosing [20].

The two paths met in January 2023, when the FDA cleared Tidepool Loop as an iAGC [11][10]. Tidepool says the app originated as a patient-led initiative and is now distributed by Sequel Med Tech as twiist Loop [21]. Sequel's labeling describes the twiist Loop algorithm as working with compatible iCGMs and the twiist ACE pump [16]. Community-built software raises its own security questions, which we cover in Security Risks in Open-Source AID Communities.

Security travels with every connection

Every wireless link between a sensor, a phone and a pump is a possible way in, which is why the ACE pump rule begins its interface requirements with secure pairing [2]. The FDA's cybersecurity page includes two communications about insulin pumps. In June 2019 it reported potential cybersecurity risks in certain Medtronic MiniMed Paradigm pumps and recommended replacing them with better-protected models. In September 2022 it said a nearby unauthorized person could exploit the communication protocol of the MiniMed 600 series, which includes the 630G and 670G. If that happened, the pump could deliver too much or too little insulin [22]. Our article on cybersecurity in connected CGM ecosystems goes further into how these links are protected.

What the FDA categories don't settle

The regulations set what each device must do, but each new pairing still has to be integrated and tested. Tidepool's clearance shows one way to plan for that. The FDA reviewed Tidepool's pre-specified procedures and acceptance criteria for future modifications, covering software, cybersecurity and device interoperability among other areas. The clearance defines a compatible pump as any ACE pump that meets those criteria, and says Tidepool Loop must not be distributed until they are met [11]. So a sensor can be cleared as an iCGM and still be missing from a given pump's list until that pairing is done. As of October 2026, Tandem lists the FreeStyle Libre 3 Plus for the t:slim X2 but not for Tandem Mobi, even though both pumps run Control-IQ+ [14]. The maker's compatibility page remains the place to check.