Goose: The Open-Source App That Unlocks WHOOP 5.0 Hardware Without a Subscription

In its current state, the app can:

• Pull raw biometric data directly from the band over Bluetooth LE, including real-time heart rate, SpO2, heart rate variability (HRV), skin temperature, and accelerometer readings .
• Track activity and sleep sessions locally .
• Export the collected data to Apple Health, allowing users to view and use their data in other apps without ever touching WHOOP's official software .

How It Was Built in Under 24 Hours

The development timeline itself became part of the story. Bennett reverse-engineered the WHOOP 5.0's Bluetooth Low Energy protocol in roughly 23.5 hours . The developer documented the rapid-fire process on X (formerly Twitter), posting updates that moved from initial packet analysis of the band's BLE data to a functioning Swift application .

The source code was uploaded to GitHub under the repository b-nnett/goose, and it quickly went viral, being covered by tech outlets ranging from Android Authority to Numerama . The project also follows a lineage of similar reverse-engineering efforts. Another developer had previously released my-whoop, an open-source iOS client for the WHOOP 4.0, and a separate project called GoWhoop targeted the same generation . These earlier projects demonstrate a sustained interest in extracting value from WHOOP hardware independently of the company's subscription platform.

Why It Matters: The Subscription Trap

WHOOP's business model is unusual for a hardware company. While the band itself is sometimes offered at a low upfront cost or even for free, accessing any data from it requires an active membership. As of the WHOOP 5.0 generation, the cheapest plan, WHOOP One, costs $199 per year, with the WHOOP Peak tier priced at $299 per year and WHOOP Life (paired with the WHOOP MG band) at $399 per year .

The band has no screen. Without the paid app, it displays nothing and does nothing that a user can interact with . Goose's purpose is to expose a simple but hidden reality: the sensor data itself is accessible at the BLE level. The subscription doesn't pay for the biometric data—it pays for the cloud-based analytics and algorithmic insights that WHOOP builds on top of that data .

By creating a local-first reader, Goose draws a clear line between raw hardware utility and the value of proprietary software. It asks, in effect: how much of the $199 per year is for the sensors, and how much is for the Strain Score?

What Goose Can’t Do (The Big Limitations)

Goose is not a replacement for the official WHOOP app, and it isn't trying to be. Understanding its current limits is essential for anyone curious about using it.

It’s Raw and Experimental

This is a developer's proof of concept, not a polished consumer product. It is not available on the App Store, and installing it requires technical knowledge—likely building the app from source or sideloading it onto an iOS device .

No Proprietary Analytics

WHOOP’s core value proposition lives in its algorithms: the Strain Score, Recovery Score, Sleep Performance metrics, and personalized coaching recommendations are all computed on WHOOP's servers . Goose reads the raw sensor feeds, but it cannot reproduce these scores. Users who rely on WHOOP's specific metrics for training decisions will find Goose provides the ingredients, not the recipe.

Local-Only, No Cloud Sync

All data stays on the device unless the user manually exports it. There are no backups, no sync across devices, and no cloud dashboard .

Legal Uncertainty

Reverse-engineering a commercial product's communication protocol can trigger terms-of-service violations or intellectual property challenges. Some early community reaction has already raised the question of whether WHOOP might pursue legal action . The Goose README presents the work as a personal research project, but the legal waters remain untested.

Device and Compatibility Boundaries

The app has been tested only on the WHOOP 5.0, and compatibility with the medical-grade WHOOP MG variant is unconfirmed. It works with Bluetooth LE on iOS, but does not support Android.

The Bigger Picture: Open Source vs. The Subscription Model

Goose didn't emerge in a vacuum. It's the latest and most visible entry in a broader ecosystem of open-source projects that reject the hardware-as-a-subscription-trap model.

Gadgetbridge remains the most mature example. This free, cloudless Android application replaces the official companion apps for devices from Xiaomi, Amazfit, Pebble, and others, allowing users to receive notifications, sync fitness data, and configure their devices without any vendor account or data transmission to external servers .

Wasp-os takes the philosophy further by replacing the firmware itself. This MicroPython-based open-source OS runs on nRF52-based smartwatches, including the PineTime from PINE64, and integrates with Gadgetbridge for a completely vendor-independent stack . The PineTime was designed specifically to run open-source software, with community projects like InfiniTime and Wasp-os providing free, user-controlled alternatives to proprietary wearable operating systems .

New hardware projects are emerging around the same principles. The UNA Watch, a modular, repairable GPS sports watch from a Scottish indie brand, launched with a promise of no subscriptions and user-installable hardware upgrades like music storage and a microphone module . Around the same time, preorders opened for the rebooted Pebble Core watches, signaling renewed interest in hardware that users truly own .

These efforts converge on a single insight: the sensors in these devices generate data that belongs to the person wearing the band. The subscription fee isn't for the biometrics themselves—it's for a particular interpretation of them. Open-source projects demonstrate that the data is readable at the protocol level, and as more developers prove this, the pressure builds on wearable companies to either justify ongoing fees with genuinely superior analytics or watch their locked-in user base erode as free alternatives mature.

For now, Goose remains a rough prototype built by one developer in a single day. But it's a prototype that has resonated because it makes visible something many users have long suspected: the hardware in their hands is capable of more than the subscription model lets them see.