Messaging
Nostr supports two broad messaging paradigms: private one-to-one or small-group DMs, and public channels that work more like group chats or chat rooms. Let’s break them both down.
Private Direct Messages
Section titled “Private Direct Messages”Modern private messaging on Nostr uses NIP-17, which is built on top of a layered encryption stack. It uses gift wrapping and sealed sender patterns to protect both the message content and the metadata — who’s talking to whom.
The encryption chain works like this: NIP-17 wraps NIP-59, which wraps NIP-44. NIP-59 provides the gift wrap layer that hides metadata like the sender and recipient. NIP-44 handles the actual encryption of the message payload with versioned encryption that supports larger messages and better security than older approaches.
If you’re coming from an older client, you might have seen NIP-04 mentioned. That was the original DM spec. It works, but it has some real downsides: there’s no forward secrecy, and the metadata (who sent a message to whom) is visible to anyone watching the relays. It’s deprecated in favor of NIP-17, but some clients still support it for backwards compatibility. If you have a choice, use NIP-17.
Public Channels
Section titled “Public Channels”For group conversations that are visible to anyone, NIP-28 defines public channels. There are three key event types here: kind 40 creates a channel, kind 41 updates channel metadata (name, description, image), and kind 42 is a channel message. Channel creators can also set up moderation by defining who’s allowed to post.
Channels are public by design — anyone who knows the channel ID can read the messages. Think of them like IRC channels or public Discord channels.
Relay-Based Groups
Section titled “Relay-Based Groups”NIP-29 takes a different approach to groups. Instead of public channels on open relays, NIP-29 defines groups where membership and permissions are managed by a specific relay. The relay acts as the group server — it controls who’s in the group, who can post, and who has admin privileges.
This model is more centralized than public channels, but it gives group administrators real control over membership and moderation. The relay enforces the rules, rather than relying on client-side filtering.
Which Should You Use?
Section titled “Which Should You Use?”- Private conversation? Use NIP-17 with a client that supports it.
- Public chat room? Use NIP-28 channels.
- Managed group with access control? Use NIP-29 relay-based groups.