Nick Szabo’s 1999 essay “Micropayments and Mental Transaction Costs” explores why micropayments have been slow to take off in the internet economy. He argues that while technical solutions can reduce the cost of processing payments, the real hurdle lies in the mental effort users must spend evaluating each transaction—what he calls the “mental transaction cost.” In Keychat, users make micropayments by sending sat stamps to the relay or sats to the bot. But these payments don’t suffer from the mental overhead Szabo described. Why? Because the price is fixed—1 sat equals 1 stamp—and the payment process is completely automated by the app. There’s no need for the user to stop and think each time they send a message.

Micropayments and Mental Transaction Costs | Satoshi Nakamoto Institute

Advancing and preserving bitcoin knowledge

Offline Me needs self-controlled IDs and wallets to live in the physical world. Online Me also first needs self-controlled IDs and wallets to live in the digital world. Then Me can chat and browse. In Chat, Me uses the IDs and pays for relays per message with the wallets. In Browser, Me uses the IDs to log in to mini apps and pays in Bitcoin with the wallets.

While using these web apps, if you come across an "Extension Login" option, you can log in with your Keychat ID by clicking it. Similarly, when you encounter a Lightning Network invoice and an "Open Wallet" button, clicking it will allow you to pay using your Keychat Wallet.

Prioritize app development in domains with the highest user engagement and adoption. View quoted note →

ID+Wallet, Chat+Browser. We believe that user-sovereign ID+Wallet is the foundation, upon which the Chat+Browser functionality is built. This is also the reason behind our design choice for the left sidebar.

Keychat encourages users to use multiple IDs (derived from the same seed phrase). As shown below, one ID is “Satoshi” for chatting with friends, and another is “Bot” for talking to the AI bot.

Keychat users can ask the AI bot questions and pay per message with ecash Cashu sats. This is different from the sat stamp paid to the relay — it’s paid to the bot.

Using Jumble on Keychat for macOS

We submitted Keychat to the App Store and Google Play last Monday, and it’s currently under review. In the meantime, the Android APK and macOS version are available for download at:

Keychat APP

Keychat is the super app for Bitcoiners. Autonomous IDs, Bitcoin ecash wallet, secure chat, and rich Mini Apps — all in Keychat.

If you’re an existing Android user, please note that the new version of MLS groups is not compatible with the previous one. After upgrading, you will no longer have access to your old MLS groups.

ID+Wallet, Chat+Browser View quoted note →

Mini app

Keychat first learned from Signal, and then from WeChat. However, the user autonomy in Keychat (ID + Money) is something that neither Signal nor WeChat offers. View quoted note →

Neither early nor late, the timing is just right. View quoted note →

Some updates: We've finally sorted out the Apple developer account. We expect to release the iOS version of Keychat within a week or two, and possibly a macOS version as well (although the UI isn’t fully optimized for large screens yet). We're currently revising our MLS group implementation. We've studied the codebases of NIP-104 and White Noise in depth and learned some useful design ideas—such as encrypting MLS messages using NIP-44 and hiding the `group_ID`. We’ve also been posting comments and discussing better mechanisms, like more efficient ways to update the MLS group’s receiving addresses. Ultimately, we hope different MLS clients will be able to interoperate.