Before you use Nostr: Five Key Concepts to Recognize
Published on 27 Apr 2026
Before you create your first identity or post your first note, there are five core ideas worth knowing: public keys, private keys, identity, clients, and relays.
You know what Nostr is, and you want to get started.
Before you do, it’s a good idea to grasp the five key concepts.
This won’t involve lengthy explanations or homework.
But understanding the concepts behind the implementations of Nostr makes the experience better. This information will help you avoid errors and use Nostr successfully from Day 1.
Concept 1: Public Key
A Nostr public key is like your home address. Anyone can know it and use it to send you mail, but knowing it doesn't let them inside your house. Sharing your public key freely lets people find and verify you.
A Nostr public key exists in two forms. Under the hood, it's a long string of letters and digits. What you'll actually see, copy, and share is its readable version: a code that always starts with 'npub', so you can tell at a glance what kind of key it is.
Example of a Nostr public key:
npub1sn0wdenkukak0d9dfczjxnapgcyz0zg4pkg4hp5ghe0yz4rfl5eqsm2gpa
Concept 2: Private Key
Your private key, by contrast, is the house key that only you hold, proving you're the real owner.
A Nostr private key is the one thing that proves you own the place and lets you lock or unlock every door. This master key allows you to take actions (sign messages, publish notes, send encrypted DMs, react to posts, create and edit contact lists, etc.)
A Nostr private key works the same way. There's a technical form, and a readable form that always starts with 'nsec'. That prefix matters: it tells you instantly that you're handling something secret, not a public key.
Example of a Nostr private key:
nsec1vl029mgpspedva04g90vltkh6fvh240zqtv9k0t9af8935ke9laqsnlfe5
IMPORTANT: If someone else gets a copy of your private key, they can control your Nostr identity and take actions with it. You must guard it fiercely and never lose it. There is no ‘forgot password’ button. Storing your ‘nsec’ in a password manager is a good first step to take. Find out more about key management here.
Concept 3: Identity
Nostr identities work with cryptographic key pairs (public and private).
Nostr clients (apps or services) generate your identity when you instruct them to take action.
If this is the first time you are creating an identity, remember to note down and store your private key.
If you already have an identity, you can sign in by using your private key.
Note: it is best to use an extension or device to store your private key, rather than pasting it into apps and sites.
Identities are different from accounts.
Account credentials can be revoked by a service (e.g., getting banned by YouTube or X). Identities belong only to you and are interoperable with any Nostr service.
There is a raft of different uses for Nostr identities in addition to social media profiles: Medical records, customer loyalty profiles, professional credentials, media subscriptions, reputational capital, event ticketing, device authorization, voting and governance, and many more uses.
As the ecosystem grows and your identity gathers more valuable information, it is crucial that you (and only you) remain in full control of your data and the ability to take action across a host of clients and services.
Concept 4: Client
A Nostr client is simply an app or interface that connects to the Nostr protocol and lets you read, write, and interact with content, the same way an email client like Gmail or Outlook lets you use the email protocol.
The client doesn't own your data or identity; it's just a window into the network. Examples include Damus (iOS), Amethyst (Android), and Primal (web), and you can switch between any of them using the same key pair without losing anything.
These clients are quite different from centralized social media platforms. The user chooses how content displays, and there's no algorithm deciding what you see. Most popular Nostr clients show you a chronological feed from people you follow.
There is no central control of what content is promoted, blocked, or displayed on Nostr. Nostr clients simply present an interface for you to interact with the protocol. You choose how to use it.
Concept 5: Relays
Relays are servers that store and forward your messages. You can connect to many relays at once, and anyone can run one. If one relay goes down or censors you, your content still lives on others. This is what makes Nostr a decentralized protocol that remains highly censorship-resistant.
Most clients offer default relays to users, but you can choose different relays or even run your own.
Now you have the knowledge you need to get started on Nostr
There is plenty more to learn, but now you know about these 5 key concepts, you’ll have a smoother onboarding process and will be able to use Nostr successfully from Day 1.