The TypeScript client for the Formfeed API: generate PDFs and images from templates, and fill Word and PowerPoint templates. It has no dependencies and uses only Web APIs (fetch, Web Crypto), so it runs in Node 22+, Deno, Bun, Cloudflare Workers and browsers.

Retries 429 and 503 with the server's Retry-After.
Sends an Idempotency-Key with every render, so a retried request never renders twice.
Turns API problems into FormfeedError with code, status and request_id.
Verifies webhook signatures.

npm install @formfeed/sdk

Render a template

import { Formfeed } from '@formfeed/sdk';

const client = new Formfeed({
  apiKey: process.env.FORMFEED_API_KEY!,
  region: 'eu',
});

const render = await client.renders.create({
  template: 'invoice-de',
  data: {
    invoice: {
      number: '2026-0042',
      lines: [{ description: 'Consulting', qty: 8, price: 120 }],
    },
  },
});
console.log(render.download_url, render.page_count);

const pdf = await client.renders.download(render); // the bytes

Async renders and batches

const queued = await client.renders.create({
  template: 'invoice-de',
  data,
  mode: 'async',
});
const done = await client.renders.waitFor(queued.id);

const job = await client.renders.batch({
  template: 'invoice-de',
  items: orders.map((order) => ({ data: { invoice: order } })),
  zip: true,
});
const finished = await client.jobs.waitFor(job.id);

Word and PowerPoint

import { readFile } from 'node:fs/promises';

// a template is a .docx or .pptx with tags such as {{ customer.name }} in its text
await client.templates.create({
  name: 'Offer',
  slug: 'offer',
  kind: 'docx',
  engine: 'jinja2',
  file: { data: await readFile('offer.docx'), name: 'offer.docx' },
  publish: true,
});

const filled = await client.renders.create({
  template: 'offer',
  output: 'docx',
  data,
}); // or output: 'pdf'

// a new version with a new document; without `file` the latest document is kept
await client.templates.versions.create('offer', {
  file: { data: await readFile('offer-v2.docx'), name: 'offer.docx' },
});
const docx = await client.templates.versions.file('offer', 'latest'); // the document's bytes

// any office document to PDF (Word, Excel, PowerPoint, OpenDocument, RTF)
const pdf = await client.pdf.convert(
  { file: { data: await readFile('report.xlsx'), name: 'report.xlsx' } },
  { single_page_sheets: true },
);

Webhooks

import { parseWebhookEvent } from '@formfeed/sdk';

// pass the raw request body, not re-serialised JSON; throws when the signature does not match
const event = await parseWebhookEvent(
  secret,
  request.headers.get('webhook-signature'),
  rawBody,
);
if (event.type === 'render.completed') console.log(event.data); // the render object