What is Nostr, and what are zaps?

Nostr is an open protocol for social media and other apps in which users are identified by cryptographic keys rather than accounts held by a company. The name stands for Notes and Other Stuff Transmitted by Relays. Many Nostr apps also support zaps, which are tips paid in bitcoin over the Lightning Network.

How does the Nostr protocol work?

Nostr has two parts, clients and relays. A client is the app you use. A relay is a simple server that stores and passes on messages, and anyone can run one with their own rules. When you post, your client sends the message to several relays, and people who follow you read it from those relays.

Every post, called an event, is signed with your private key using Schnorr signatures on the secp256k1 curve, following Bitcoin's BIP-340 standard, as set out in NIP-01. Clients check the signature, so a relay cannot change your post without it being detected. The protocol's README argues this makes Nostr hard to censor, because if one relay drops you, any other relay that accepts you can still carry your posts. It also admits weak points, such as relays being able to withhold or misrepresent data and the difficulty of finding which relays hold a given person's notes.

What are Nostr keys, npub and nsec?

Your Nostr identity is a key pair, much like a crypto wallet's keys. NIP-19 defines friendly text formats for sharing them. An npub is your public key, which you can give out like a username. An nsec is your private key, which signs everything you post.

There is no password reset. Anyone with your nsec can post as you, and if you lose it you cannot get the identity back. Treat it with the same care as a seed phrase, and be cautious about pasting it into apps you do not trust.

What are Nostr zaps?

Zaps are Lightning payments linked to a Nostr profile or post. According to nostr.how, sending one takes a few seconds. Your client contacts the recipient's Lightning address, builds a signed zap request, receives a Lightning invoice and passes it to your wallet to pay. The recipient's server then publishes a zap receipt to relays, and apps show the zap next to the post.

To receive zaps, you add a Lightning address to your Nostr profile and use a Lightning wallet that supports them. NIP-57 notes that zaps can serve as tips or as a way to deter spam.

Is a zap a proof of payment?

No. The NIP-57 specification states plainly that a zap receipt is not a proof of payment. It shows that an invoice was requested and that the recipient's server says it was paid, so it depends on trusting that server. As of November 2026, NIP-57 is still marked as a draft, optional standard, and features differ between Nostr apps and wallets.