9 Minutes
Bitchat grows beyond offline mesh to location-based messaging
Jack Dorsey has revealed a major expansion for Bitchat, his experimental messaging app: "location chat," a feature that assigns users to local chat rooms based on their geographic region. The update shifts the project’s emphasis from short-range Bluetooth mesh networking to city-scale, location-aware conversations while keeping privacy and decentralized principles central to the design.
This addition maps users into discrete chat channels using geohashes — encoded grid squares that represent neighborhoods, blocks or larger regions — and assigns temporary pseudonyms for each grid. Messages still flow over Nostr relays, a decentralized relay protocol Dorsey has long supported and that already integrates Bitcoin Lightning features. The release is currently under App Store review.
How Bitchat started: mesh networking and offline messaging
Bitchat began life as a short-range, offline messaging experiment. The initial beta, released via Apple TestFlight in early July, used Bluetooth to relay messages across devices within roughly 300 meters. That design created mesh networks that could pass messages without an internet connection or cellular coverage — useful in outages, crowded events, or places with restricted connectivity.
The beta included a technical white paper outlining cryptography and messaging behavior: Curve25519 key exchange, AES-GCM encryption, file fragmentation, duplicate suppression, and an emergency "panic mode" that wipes all stored data on demand. Dorsey noted from the outset that the code had not yet been through an independent security audit, underscoring the experimental status of the project.
What "location chat" changes
Location chat expands Bitchat’s scope from neighborhood mesh hops to persistent, region-based chat rooms. Instead of relying only on Bluetooth to propagate messages across nearby devices, the app will create geohash-defined channels that route posts via Nostr relays. Users appear in a room for the geohash covering their area and receive a fresh pseudonym for that grid cell — an approach designed to reduce the need for phone-number identity while preserving a degree of anonymity.
Geohashes: grid-based location without exact coordinates
Geohashes convert latitude and longitude into short alphanumeric strings that represent squares on a map. Shorter codes cover larger areas; longer codes pinpoint smaller tiles. For example, a six-character geohash approximates a one-square-kilometer area — large enough to group people by neighborhood while obfuscating precise positions. In Bitchat, each geohash becomes a chat room, and moving to a new tile gives the user a new ephemeral handle.
Nostr relays: decentralized transport for messages
Instead of centralized servers, Bitchat uses Nostr, an open protocol made of independent relays. Anyone can run a Nostr relay and users can choose which relays to publish to or read from. This design avoids a single point of control: if one relay fails, other relays continue to carry messages. By layering geohash rooms on top of Nostr, Bitchat aims to deliver resilient, censorship-resistant local chat.
Lightning and payments: native micropayments on Nostr
Payments are embedded in the broader stack. Nostr Improvement Proposals (NIPs) like NIP-57 and NIP-47 standardize Lightning-integrated features: NIP-57 introduces "zaps" (Lightning tips recorded as Nostr events) and NIP-47 enables secure wallet connections. That means tipping, micro-fees to post, or instant peer-to-peer transfers can be built directly into the chat experience using Bitcoin’s Lightning Network.
Why crypto primitives matter for chat
Bitchat is not just another messenger because its stack blends location primitives, decentralized relays, and Bitcoin-native payments. That combination unlocks use cases and defenses that centralized chat apps can’t deliver without extra infrastructure.
Spam control and anti-bot measures
Traditional platforms fight spam with phone verification or moderation teams. On Nostr, communities already use zaps — tiny Lightning payments measured in satoshis — as a low-cost gate. A refundable or negligible micro-fee can discourage mass automation while remaining trivial for genuine users. Applied to location rooms, pay-to-post mechanics could keep local conversations cleaner without centralized moderation.
Local commerce and tipping
Lightning’s instant, low-fee payments are uniquely suited to casual transactions: tipping a busker, buying a neighbor’s used item, or posting a small reward for help. In 2024, Nostr clients like Damus processed millions of Lightning zaps, showing user comfort with tiny in-app Bitcoin transfers. Integrating Lightning into geohash rooms could turn Bitchat into a lightweight local marketplace.
Resilience during outages
When internet access is unreliable or blocked, Bluetooth mesh can maintain short-range connectivity while Lightning can enable value exchange when payments are possible. Mesh messaging has proven useful in crises — for example, during the 2019 Hong Kong protests, Bridgefy downloads surged because it worked without cell coverage. Bitchat aims to blend that offline durability with native payments, potentially useful in emergencies or censorship scenarios.
Privacy enhancements
Some Lightning wallets now use token-based systems like Cashu to create Bitcoin-backed, anonymous tokens. If integrated thoughtfully, these privacy tools could let Bitchat users exchange value inside location rooms with a cash-like level of anonymity, reducing traceability compared with on-chain transfers.
Technical reality check: what’s tested and what isn’t
Individually, the layers Bitchat uses are well-established: geohashes are common in mapping; Nostr has been live since 2020; Lightning handles millions of micro-payments monthly. Bitchat’s experiment lies in combining them into an everyday social and payments tool — a nontrivial engineering, policy and user-experience challenge.
Bitcoin Lightning Network capacity chart | Source: Bitcoin Magazine Pro
One contentious metric is public channel capacity. Headlines have noted a drop in public Lightning capacity from roughly 5,400 BTC in 2023 to close to 3,800 BTC by August 2025. Critics claim this signals weakening adoption, while proponents argue capacity alone is a poor proxy for the network’s health: modern wallets route payments more efficiently, and reported success rates remain above 98%. Both views influence perception and, potentially, user confidence in Lightning-powered features inside Bitchat.
Policy, privacy and economic hurdles
Bitchat will face several real-world tests before it can transition from proof-of-concept to mainstream utility.
Platform rules and app stores
Apple has previously restricted how Lightning payments integrate with content in apps. In 2023, the Damus client had to remove per-post Lightning zaps on iOS; Apple only allowed tipping at the profile level, citing in-app purchase rules. If Bitchat implements pay-to-post or per-message tipping in location rooms, App Store policies could block those features unless a compliant approach is found.
Privacy limits of geohashing
Geohashes reduce precision, but patterns of repeated activity in the same grid can reveal behavior over time. Even with per-grid pseudonyms, consistent presence in a tile can allow inferences about where someone lives, works, or frequently visits. Maintaining anonymity at scale will demand careful design, usage guidance, and possibly technical mitigations like rotating geohash granularity or time-limited pseudonyms.
Relay economics and decentralization risks
Nostr relays need bandwidth and uptime. If only a few well-funded relays end up shouldering city-level traffic, the architecture could drift back toward centralization. Questions remain about sustainable funding models for relays — subscriptions, donations, or Lightning-based fees — and how to prevent concentration of control.
Real-world adoption: what will decide Bitchat’s fate?
Several practical outcomes will determine whether Bitchat becomes a widely used social layer for Bitcoin or stays an instructive experiment:
- Platform compatibility: Can the app navigate App Store rules and still deliver Lightning-integrated features?
- Privacy and safety: Does the geohash/pseudonym approach protect users against de-anonymization over time?
- Payment reliability: Will Lightning routing and liquidity provide smooth, low-fee zaps for millions of micro-transactions?
- Relay health: Can a diverse, resilient relay ecosystem scale to handle city-level messaging without recreating centralized control?
If Bitchat can answer these questions positively — and if users adopt location rooms and Lightning payments — the app could represent the first practical social layer built on Bitcoin-native rails. If not, it will remain a useful prototype that surfaces design trade-offs and technical limitations.
Use cases to watch
Practical examples where this combination might shine include:
- Neighborhood coordination: local buy/sell posts, lost-and-found, or community alerts with small paid pins to deter spam.
- Local services: paying a neighbor for a quick job or tipping a street artist with instant Lightning payments.
- Event coordination and safety: offline mesh fallback during crowded concerts or protests, combined with later settlement via Lightning.
- Micro-bounties: posting tiny rewards to crowdsource quick answers or help.
Conclusion: an experiment with potential
Bitchat’s move from Bluetooth-based mesh to geohash-enabled, Nostr-relayed, Lightning-capable location chat is an ambitious attempt to combine decentralized messaging with native crypto payments. The building blocks are proven individually, but integrating them at scale will test platform policies, user privacy, payment reliability and relay economics. For crypto and Bitcoin communities, Bitchat will be an important experiment to watch: it could either point the way to a new social layer built on permissionless rails — or provide hard lessons for future projects aiming to blend location, messaging and money.
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