# Nostr

**Canonical:** https://apis.io/providers/nostr/  
**Website:** https://nostr.com/  
**APIs profiled:** 4

Nostr (Notes and Other Stuff Transmitted by Relays) is an open, permissionless protocol for censorship-resistant social and messaging applications. Identity is a public/private keypair; content is a signed JSON event; transport is a WebSocket connection to one or more relays. There is no central server, no canonical API, and no organization that owns the protocol — only a set of community-defined NIPs (Nostr Implementation Possibilities) describing event kinds, relay behavior, and client conventions. A large ecosystem of clients (Damus, Amethyst, Coracle, Yakihonne, Nostur, Iris), relay implementations (strfry, nostream, khatru), and language libraries (nostr-tools for JS, python-nostr, go-nostr, rust-nostr, NDK) has formed around the protocol. Nostr is profiled here through its specifications and reference implementations rather than a vendor API.

## Kin Score — 31.1 / 100 (thin)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 31.1).

| Facet | Score |
|---|---|
| Discoverability | 74.1 |
| Contract Quality | 45.6 |
| Governance | 11.4 |
| Contract Governance | 11.4 |
| Operational Transparency | 39.5 |
| Developer Ergonomics | 0.0 |
| Commercial Clarity | 28.9 |
| Access Clarity | 28.9 |

## Agent readiness — 19.7 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | derived |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Free — onboarding: unknown, pricing: free, trial: no (confidence: medium).

## APIs (4)

- **Nostr Protocol (NIP-01)** — NIP-01 defines the core Nostr protocol: event format (id, pubkey, created_at, kind, tags, content, sig), client-to-relay messages (EVENT, REQ, CLOSE), and relay-to-client messag...
- **Nostr Implementation Possibilities (NIPs)** — NIPs are the standards documents that extend Nostr beyond the core protocol. They define event kinds (text notes, reactions, zaps, long-form articles, DMs, calendar events, mark...
- **Nostr Relay WebSocket Interface** — A Nostr relay is a WebSocket server that accepts signed events, stores them subject to its own policy, and responds to subscription filters from clients. The relay surface is in...
- **nostr-tools JavaScript Library** — nostr-tools is the de-facto JavaScript/TypeScript library for Nostr clients and bots. It implements event creation, signing, relay connections, subscription filters, and many co...

## Security (1)

- **Nostr Domain Security** — TLSv1.3

## Plans (1)

- **Nostr Plans Pricing**

## Tags

Nostr, Decentralized Social, Open Protocol, Relays, WebSocket, Signed Events, NIP, Censorship Resistant, Self-Sovereign Identity

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/nostr/). Scores are computed from the provider's own public artifacts under a published rubric.