Nostr Shard Signer — Developer Portal

Developer Portal

Nostr Shard Signer gives any web app a window.nostr signer — no browser extension required. One script tag, two login paths:

🔐 Web3Auth OAuth

Users log in with Google, Apple, or X — no existing Nostr key needed. The key is derived via MPC and held exclusively inside a sandboxed cross-origin iframe, never touching the parent page's memory.

🗝️ NIP-46 Bunker via window.nostr.js

Users who already hold their own Nostr key can connect via any NIP-46 remote signer — nsec.app, Amber, or a self-hosted nsecbunker. The bridge loads window.nostr.js as the signing backend; the parent app never sees the private key.

This portal lets you register your Web3Auth clientId and allowed domains so the signer trusts your app. Connect a Nostr key (Alby or any NIP-07 extension) to get started, or read the docs first.

Register a new clientId

Binds your Web3Auth clientId to an allowed domain. First-come first-served — the claim is published as a NIP-33 event signed by the registry root key.

Web3Auth Client ID Allowed Domain

Update allowed domains

Two-phase ownership proof: a nonce is issued, you sign it with the npub that owns the clientId, then the domain list is replaced atomically.

1Enter your clientId and fetch a challenge nonce.

2Your connected Nostr key signs the nonce (kind 27235).

3The signed event is submitted as proof — domains are updated.

Web3Auth Client ID Allowed Domains

My Registrations

Fetches your NIP-33 registration events directly from Nostr relays — no server lookup required.