Cashu Developer Sends Bitcoin (BTC) Over Apple's Find My in 2-Bit Broadcasts

A Developer, an ESP32 and Apple's Find My

A Cashu developer has pushed a Bitcoin (BTC) transfer across Apple's Find My network from a device that never touches the internet, announcing the result on X on September 30, 2026. In the announcement, calle, who created the Cashu ecash protocol, calls it possibly the most absurd medium for sending bitcoin yet. The test is a payment-rail experiment rather than a market event, and it left the Bitcoin price untouched.

@callebtc · X post

The announcement.

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Cashu is an ecash protocol built to keep Bitcoin payments private through bearer tokens issued by mints, a model that sits at the outer edge of Bitcoin DeFi experimentation. The open-source code behind the test, published in the find-my-nuts repository, runs on cheap ESP32 microcontroller boards. The device packs a Cashu token into Bluetooth signals that imitate the beacons of a lost item, convincing passing iPhones to relay tiny fragments of data. Those handsets forward what they hear through Apple's Find My network, the tracking system behind AirTags, exactly as they would report a missing AirTag. The recipient, signed in with an Apple account, pulls those reports and rebuilds the token piece by piece; a Python script then validates the reassembled token for errors before it is printed.

Bandwidth is the constraint. AirTag beacons exist to carry a location fix, not a payload, and each broadcast in this experiment moves just two bits of data. A typical token therefore needs more than 1,000 separate broadcasts before the full token reaches its destination. The sending device itself requires no internet connection at any point in the transfer. The result turns consumer tracking infrastructure into an unintended message bus for value.

Public Tokens, No Encryption

The same developer is blunt about the design's central weakness: every token broadcast over the network is public. Cashu tokens behave like digital cash, so whoever recovers one first can spend it, and recovery is not limited to the intended recipient. The weak point is the transport itself. According to the protocol notes, the payload travels unencrypted, and the identifiers used to retrieve the reports are public. In practice, an observer holding an Apple account and the right IDs could reconstruct a token while it is still in flight.

The documentation therefore advises sending only giveaway amounts, and warns that delivery is slow, unofficial and carries no guarantee. The receiving side adds its own fragility: it taps Apple's Find My network through an unofficial interface, so the tool could stop working outright if Apple changes that interface. Because each broadcast carries only two bits, a token in transit exists as scattered fragments, and the pieces become spendable only once the recipient has collected enough reports. Borrowing the AirTag beacon format is what makes the relay possible at all, since payment traffic looks indistinguishable from ordinary tracking reports to the phones doing the forwarding.

For all those caveats, the Find My test remains a novelty rather than a payment product. It still joins a broader effort to make Bitcoin (BTC) payments feel like sending a text message, only this time without any internet connection. Other developers are attacking the same privacy problem from a different direction, chasing private transfers on the base Proof of Work layer instead of borrowing Apple's infrastructure.

Where Offline Payments Go Next

In COINOTAG's reading, the threads of this story point the same way: the hardest part of offline Bitcoin payments is not the money but the messenger. The find-my-nuts documentation, the primary record behind the experiment, states plainly that the payload travels unencrypted and that the lookup identifiers are public, which caps the tool at tip-sized transfers for now. Privacy routes for moving BTC, whether ecash bearer tokens or Wrapped Bitcoin designs on other chains, all lean on infrastructure outside the base layer, and the Find My test simply borrows the strangest infrastructure yet. If Apple ever closes the unofficial interface the receiver depends on, the novelty ends there.