docjet

Official JavaScript/TypeScript SDK for DocJet — the document generation API for AI agents and automation builders.

Send a template ID or raw HTML plus data; receive a branded PDF or PNG in seconds.

Install

npm install docjet

Requirements: Node.js 18+ (native fetch required). Zero runtime dependencies.

Quickstart

import { DocJetClient } from 'docjet';

const client = new DocJetClient({ apiKey: 'binfra_your_api_key_here' });

// Render a PDF — returns a signed download URL
const { url } = await client.render({
  template_id: 'invoice-ro',
  data: {
    client: 'Acme SRL',
    total: 1500,
    currency: 'RON',
  },
});

console.log('PDF ready:', url);
// https://api.docjet.dev/v1/outputs/abc123?exp=...&sig=...

Render from raw HTML

const { url } = await client.render({
  html: '<h1>Hello World</h1><p>Generated by DocJet.</p>',
  data: { name: 'World' },
});

Render a PNG image

const { url } = await client.renderImage({
  template_id: 'og-card',
  data: { title: 'My Article', description: 'Summary here' },
  width: 1200,
  height: 630,
});

List available templates

const templates = await client.listTemplates();
// [{ id: 'invoice-ro', name: 'Invoice RO', outputType: 'pdf', ... }, ...]

Check API key usage

const usage = await client.usage();
console.log(`Used ${usage.used}/${usage.limit} renders this ${usage.period}`);
// Used 42/1000 renders this 2026-06

Webhook Signature Verification

The differentiator most doc APIs skip: verifyWebhookSignature lets you authenticate incoming DocJet webhook callbacks before trusting them.

Every DocJet webhook POST includes an X-DocJet-Signature header. Verify it before processing:

import { verifyWebhookSignature } from 'docjet';

// In your webhook handler (Express, Fastify, Hono, etc.):
app.post('/webhooks/docjet', (req, res) => {
  const rawBody = req.body; // raw string BEFORE JSON.parse — critical!
  const signature = req.headers['x-docjet-signature'] as string;
  const secret = process.env.DOCJET_WEBHOOK_SECRET!;

  if (!verifyWebhookSignature(rawBody, signature, secret)) {
    return res.status(401).json({ error: 'Invalid signature' });
  }

  const event = JSON.parse(rawBody);
  // event.type === 'render.complete', event.jobId, event.url ...

  res.json({ received: true });
});

verifyWebhookSignature API

verifyWebhookSignature(
  rawBody: string,          // Raw request body string (before JSON.parse)
  headerValue: string,      // X-DocJet-Signature header value
  secret: string,           // Your per-key webhook signing secret
  toleranceSeconds?: number // Replay window in seconds (default: 300)
): boolean

Security properties:

• HMAC-SHA256 over ${timestamp}.${rawBody} — exact inverse of server signing
• Timing-safe comparison (timingSafeEqual) — no early-exit hex compare leaks
• 5-minute replay window — captured signatures expire after 300s (configurable)

Error Handling

import { DocJetClient, DocJetError } from 'docjet';

const client = new DocJetClient({ apiKey: process.env.DOCJET_API_KEY! });

try {
  const { url } = await client.render({ template_id: 'invoice-ro', data: {} });
  console.log(url);
} catch (err) {
  if (err instanceof DocJetError) {
    console.error(`DocJet error [${err.code}] HTTP ${err.statusCode}: ${err.message}`);
    // err.code: 'AUTH_INVALID' | 'QUOTA_EXCEEDED' | 'RATE_LIMITED' | 'TEMPLATE_NOT_FOUND' | ...
    // err.statusCode: 401 | 429 | 404 | 422 | 500 | ...
  } else {
    throw err; // re-throw unexpected errors
  }
}

Error codes

| Code | HTTP | Meaning | |------|------|---------| | AUTH_INVALID | 401 | API key missing or invalid | | PAYLOAD_INVALID | 422 | Invalid request body or template data | | TEMPLATE_NOT_FOUND | 404 | Template ID does not exist | | RATE_LIMITED | 429 | Per-minute rate limit exceeded | | QUOTA_EXCEEDED | 429 | Monthly quota exhausted | | CONCURRENCY_EXCEEDED | 429 | Concurrent render limit reached | | INTERNAL_ERROR | 500 | Server error |

Configuration

const client = new DocJetClient({
  apiKey: 'binfra_...',                        // required
  baseUrl: 'https://api.docjet.dev',           // optional, default shown
});

Try it free

Use the public demo key (rate-limited to 3 req/min, 50 renders/month):

# cURL
curl -s -X POST https://api.docjet.dev/v1/render?response=url \
  -H "Authorization: Bearer binfra_9afb57dbb6478c441ad101129fca65847f5745403f9d718b3de6d934c9b63f88" \
  -H "Content-Type: application/json" \
  -d '{"html":"<h1>Hello DocJet</h1>","data":{}}'

// SDK
const client = new DocJetClient({
  apiKey: 'binfra_9afb57dbb6478c441ad101129fca65847f5745403f9d718b3de6d934c9b63f88',
});
const { url } = await client.render({ html: '<h1>Hello DocJet</h1>', data: {} });

Get a production key at docjet.dev.

License

MIT