The War on Open APIs: Volkswagen's Block of Home Assistant
The intersection of automotive engineering and smart home automation has long been a fruitful ground for the community-driven development of unofficial APIs. However, a recent move by Volkswagen has sent shockwaves through the Home Assistant community. By requiring "client assertions," Volkswagen has effectively blocked the homeassistant-volkswagencarnet integration, cutting off thousands of users from the ability to monitor and control their vehicles from their own local dashboards.
This move is not an isolated incident but part of a broader trend of "enshittification" in the connected device ecosystem. When manufacturers move from open or reverse-engineered APIs to strict, authenticated client assertions, they aren't just increasing security—they are asserting total control over the user experience and the data generated by the hardware the user ostensibly owns.
The Technical Wall: Client Assertions and Attestation
At the heart of this conflict is the implementation of client assertions. While some users in the community have noted that client assertions are a standard feature of OAuth, the application here is used as a gatekeeping mechanism. By requiring a specific, signed assertion that only the official app can provide, Volkswagen can distinguish between a legitimate request from their own software and a request from a third-party integration like Home Assistant.
Critics argue that this is less about security and more about control. As one community member noted, it is unlikely that this security measure is "very strong," as official clients can often be spoofed by determined developers. Instead, the goal is to create a friction-filled environment where users are forced to use the official app, which is often laden with analytics and dark patterns.
A Pattern of API Closures
Volkswagen is far from the only offender. The community discussion reveals a pattern across multiple industries:
- Automotive: Polestar users have reported similar lockdowns, and BYD has reportedly used DMCA takedowns to remove repositories that enable car connectivity.
- Wearables: Garmin recently shifted toward TLS fingerprinting to block unofficial logins via libraries like
garth, leading some long-term customers to abandon the brand entirely. - Smart Home: Companies like Ring, MyQ, and Ecobee have historically closed APIs or moved features behind subscription paywalls, citing "security concerns" while prioritizing recurring revenue streams.
"Companies seem to absolutely hate it when people don't go through their shitty websites with dark patterns, misleading search results and analytics."
The Ownership Dilemma: Who Owns the Car?
This shift raises a fundamental question: when you buy a connected car, do you own the vehicle, or are you merely licensing the software that runs it? The frustration expressed by users is palpable, as the "right to repair" movement extends from physical hardware to digital interfaces.
Some argue that this is a purely capitalist transaction—if you don't like the terms, don't buy the product. However, others point out that the lack of competition in the automotive industry makes this a viable option for few. The call for legislation is growing, with some pointing to the EU Data Act, which mandates that data holders make readily available data accessible to the user in a machine-readable format.
The Path Forward: Local Control and Hardware Hacking
In response to these API lockdowns, the community is pivoting toward more resilient alternatives. There are two primary paths being explored:
- Hardware-level Interception: Some users are building CANBUS sniffers to bypass the cloud entirely, reading data directly from the car's internal network. This ensures that the data remains local and cannot be revoked by a remote server update.
- Native Compatibility: There is a shift toward purchasing devices that support native, local standards (like HomeKit or Matter) rather than relying on cloud-to-cloud integrations that are "ticking time bombs."
The Volkswagen incident serves as a cautionary tale for the modern consumer. As cars become "computers on wheels," the risk of losing control over your own hardware increases. The only permanent solution may lie in a combination of strict regulatory oversight and a return to local-first hardware architecture.