Nostr Protocol

Nostr is a collection of rules for how short messages are sent over the internet. Such shared rules are called a protocol: all programs that follow them can communicate with one another. On Nostr, you don’t send your posts to a single company, but to many independent servers called relays, which merely forward and store the messages. Instead of an account with a username and password, every user has two long sequences of numbers: a public one, which functions like an address, and a secret one, with which they prove that a post really comes from them. The name is an abbreviation of the English sentence “Notes and Other Stuff Transmitted by Relays.” The idea was developed starting in 2020 by a programmer who goes by the name fiatjaf, and it has been openly developed further ever since.

A social network without a landlord

Ordinary social networks belong to a company. That company decides which posts are visible, who gets banned, and whether the network will even still exist in five years. Anyone banned there loses their posts and contacts all at once. Nostr shifts this power: because identity is tied to one’s own key rather than to a server, no single operator can throw anyone out of the network.

This is especially interesting for journalists and activists in countries with strict censorship. If a state blocks a relay, users simply switch to another one and keep their followers. Politically, Nostr is therefore popular above all in circles critical of censorship and the market power of major platforms. Its best-known supporter is Jack Dorsey, co-founder of Twitter, who has funded development with millions of dollars' worth of Bitcoin donations.

The downside comes with the territory: what cannot be centrally deleted is also hard to moderate. Insults, fraud, and spam remain an open problem. Nostr doesn’t solve this globally, but locally — every relay and every app filters according to its own rules.

Keys, signatures, and relays

The core of Nostr is a data packet called an “event.” It contains the text, a timestamp, the author’s public address, and a digital signature. This signature is computed from the secret key and the content. Anyone can use the public address to verify that the signature matches — and no one can forge it without knowing the secret key.

You can think of the secret key as the signet ring of a medieval prince. Whoever recognizes the seal in the wax knows who wrote the letter. But whoever loses the ring or has it stolen has a real problem: on Nostr there is no customer service to reset a password. That is precisely the biggest hurdle for new users today.

The relays themselves are deliberately very simple programs. They accept events, store them, and deliver them on request. An app typically sends a post to five to ten relays simultaneously and also queries them for the posts of subscribed contacts. If one relay goes down, the others take over. Unlike with a blockchain, there is no shared chain and no requirement for consensus — each relay simply has its own inventory.

Damus, Zaps, and the Bitcoin scene

Nostr becomes most visible in apps that look like a short-message service. Well-known ones include Damus for the iPhone, Amethyst for Android, and Primal in the browser. Importantly, you can switch apps without losing your contacts, because identity and posts don’t belong to the app. Damus made headlines in 2023 when Apple had the app removed from the Chinese App Store.

A typical Nostr feature is “zaps”: small payments in Bitcoin that you attach directly to a post, often worth just a few cents. That’s why the term is usually encountered on financial sites in connection with Bitcoin and payment networks. Besides short messages, there are now also Nostr-based blogs, marketplaces, and chats.

Nostr is relevant to AI topics for another reason as well. Because posts are signed, it can be proven who published something — helpful in an age when text and images are mass-produced by machines. Compared to major platforms, Nostr remains small, with a few hundred thousand regularly active users. It should therefore be read less as a competitor to X or Instagram, and more as an experiment in how social networks without an owner might work.