@nexis-dev/justsignnow-sdk

Official TypeScript SDK for the JustSignNow API — electronic signatures with a Bitcoin-anchored audit trail.

Install

npm install @nexis-dev/justsignnow-sdk

Quick start

import { JustSignNow } from '@nexis-dev/justsignnow-sdk'
import fs from 'fs'

const jsn = new JustSignNow(process.env.JSN_API_KEY!)

// 1. Create an editor session — your user picks where to place fields,
//    invites signers, and sends from the JustSignNow UI.
const fileBase64 = fs.readFileSync('./permission-slip.pdf').toString('base64')
const session = await jsn.editorSessions.create({
  document: { fileBase64, name: 'permission-slip.pdf' },
  user: { email: '[email protected]', name: 'Ms. Johnson' },
  returnUrl: 'https://schools.app/students/123/forms?signed=1',
  metadata: { studentId: 'stu_001', formType: 'permission' },
})

// 2. Show your user the magic link (e.g. as a redirect or a button)
console.log('Editor:', session.editorUrl) // valid 30 min, single-use

// 3. Later — poll the document status (or wait for a webhook)
const status = await jsn.documents.get(session.documentId)
if (status.status === 'completed') {
  const { blob: signedPdf } = await jsn.documents.downloadSignedPdf(session.documentId)
  const { blob: cert } = await jsn.documents.downloadCertificate(session.documentId)
  // save them where you need them
}

Configuration

new JustSignNow('jsn_live_xxx', {
  baseUrl: 'https://justsignnow.com/api/v1', // override for self-host / staging
  fetch: customFetch,                        // override for tests / non-standard runtimes
})

Get an API key at https://justsignnow.com/dashboard/settings.

API surface

| Method | Description | |--------|-------------| | editorSessions.create(input) | Create a delegated editor session | | documents.get(id) | Get document status + signers + audit anchor | | documents.downloadSignedPdf(id) | Download the completed signed PDF | | documents.downloadCertificate(id) | Download the standalone certificate |

Full reference + interactive try-it: https://justsignnow.com/docs/api.

Errors

Every non-2xx response throws a JustSignNowError :

import { JustSignNowError } from '@nexis-dev/justsignnow-sdk'

try {
  await jsn.documents.get('does-not-exist')
} catch (err) {
  if (err instanceof JustSignNowError) {
    console.log(err.status)   // 404
    console.log(err.code)     // 'not_found'
    console.log(err.message)  // human-readable
  }
}

Compatibility

• Runtime : Node.js 20+, Bun, Cloudflare Workers, Edge runtimes. Uses native fetch and crypto.subtle.
• Module format : ESM only.
• Types : ships TypeScript declarations.

License

MIT — © Nexis Dev, LLC.