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Tutorial: Napplet Integration ​

This guide is for authors building a napplet that will be hosted by Kehto.

Step 1: Declare required NAPs ​

Every napplet should declare the NAPs it requires in its NIP-5A manifest build configuration.

ts
// vite.config.ts
import { defineConfig } from 'vite';
import { napplet } from '@napplet/vite-plugin';

export default defineConfig({
  plugins: [
    napplet({
      artifactMode: 'single-file',
      requires: ['identity', 'relay'],
    }),
  ],
});

Use short NAP names such as identity, relay, storage, notify, keys, media, config, resource, and connect.

Step 2: Check hosted support ​

Hosted napplets should ask the shell what it supports instead of assuming every helper is available.

ts
const canPublish = await window.napplet.shell.supports('relay');
const canNotify = await window.napplet.shell.supports('notify');

if (!canPublish) {
  document.querySelector('#status')!.textContent = 'relay unsupported';
}

Prefer graceful degradation for optional features. Required features should be declared in requires so the shell can reject or warn at load time.

Step 3: Use NAP helpers ​

Use @napplet/nap helpers or the published napplet SDK surface for NAP operations. Do not send unclassified raw envelopes unless the host/playground has explicitly documented the exception.

ts
import { relayPublish } from '@napplet/nap/relay';

await relayPublish({
  kind: 1,
  content: 'hello from a napplet',
  tags: [],
  created_at: Math.floor(Date.now() / 1000),
});

Step 4: Avoid forbidden primitives ​

Inside hosted napplet source, avoid:

  • window.nostr;
  • direct localStorage, sessionStorage, or IndexedDB persistence;
  • direct WebSocket relay connections;
  • direct signing/encryption primitives;
  • allow-same-origin assumptions.

Kehto shell mediates identity, signing, storage, relay, and host capabilities.

Step 5: Verify through the gateway path ​

Build the napplet and load it through the same gateway artifact route used by the playground:

bash
pnpm --filter ./apps/playground/napplets/<name> build
pnpm --filter @kehto/playground preview --port 4174

The meaningful proof path is /napplet-gateway/<dTag>/<aggregateHash>/index.html, not a direct dev-server file URL.