High-Throughput Async Batch PDF Rendering, Auto-Merging & Signed Webhooks in Python, TypeScript, Laravel & Go

End-of-month billing runs, payroll statements, and logistics manifest pipelines often need to generate hundreds or thousands of PDFs at once without blocking HTTP worker threads or risking duplicate renders during network retries.

1. Async Batch Rendering & Auto-Merge (POST /v1/render/batch)

Submit up to 50 documents (raw HTML, public URLs, or hosted template_id items) in a single call. Tailprint immediately returns a 202 Accepted with a job_id, processes the batch across our pre-warmed Chromium pool, optionally merges all generated PDFs into a single master PDF, and dispatches a signed webhook when finished:

curl -X POST https://tailprint.com/v1/render/batch \
  -H "Authorization: Bearer sec_live_your_api_key" \
  -H "Idempotency-Key: billing-run-2026-11-batch-01" \
  -H "Content-Type: application/json" \
  -d '{
    "merge_output": true,
    "merged_filename": "november-2026-invoices.pdf",
    "webhook_url": "https://api.yourdomain.com/webhooks/tailprint",
    "items": [
      {
        "template_id": "invoice-modern",
        "filename": "inv-1001.pdf",
        "data": {
          "invoice_number": "INV-1001",
          "issue_date": "2026-11-13",
          "seller": { "name": "Tailprint ApS" },
          "buyer": { "name": "Customer A" },
          "items": [{ "description": "Pro Tier", "quantity": 1, "unit_price": 49 }]
        }
      },
      {
        "template_id": "invoice-modern",
        "filename": "inv-1002.pdf",
        "data": {
          "invoice_number": "INV-1002",
          "issue_date": "2026-11-13",
          "seller": { "name": "Tailprint ApS" },
          "buyer": { "name": "Customer B" },
          "items": [{ "description": "Business Tier", "quantity": 1, "unit_price": 119 }]
        }
      }
    ]
  }'

2. Official Multi-Language SDK Examples (v1.4)

import { Tailprint } from 'tailprint';
const tp = new Tailprint({ apiKey: process.env.TAILPRINT_API_KEY });

const job = await tp.renderBatchAndWait({
  merge_output: true,
  items: [
    { template_id: 'invoice-modern', data: inv1 },
    { template_id: 'invoice-modern', data: inv2 },
  ],
});
console.log(job.merged_output?.download_url);

from tailprint import Tailprint
tp = Tailprint(api_key="sec_live_...")

status = tp.render_batch_and_wait(
    items=[
        {"template_id": "invoice-modern", "data": inv1},
        {"template_id": "invoice-modern", "data": inv2},
    ],
    merge_output=True,
    idempotency_key="batch-2026-11"
)
print(status["merged_output"]["download_url"])

use Tailprint\Laravel\Facades\Tailprint;

// Stream directly from a Laravel Controller:
return Tailprint::template('invoice-modern', $invoiceData)
    ->idempotencyKey('inv-' . $invoice->id)
    ->download('invoice.pdf');

client := tailprint.NewClient(os.Getenv("TAILPRINT_API_KEY"))

pdfBytes, err := client.RenderTemplate(
    ctx,
    "invoice-modern",
    invoiceData,
    &tailprint.RequestOptions{IdempotencyKey: "inv-1001"},
)