The app accepts a ?data= URL parameter containing a compressed invoice. You can generate these links from any language to create pre-filled invoices — useful for billing systems, CRMs, or automated workflows.

How it works: JSON → key compression → lz-string → URL

import LZString from "lz-string";

// Fetch the key compression map — always in sync with the app.
const KEY_MAP = await fetch("https://h1d.github.io/easypdf-lite/key-map.json")
  .then((r) => r.json());

function compressKeys(obj) {
  if (Array.isArray(obj)) return obj.map(compressKeys);
  if (obj && typeof obj === "object") {
    return Object.fromEntries(
      Object.entries(obj).map(([k, v]) => [KEY_MAP[k] ?? k, compressKeys(v)])
    );
  }
  return obj;
}

const invoice = {
  language: "en",
  currency: "USD",
  dateOfIssue: "2026-01-15",
  dateOfService: "2026-01-15",
  paymentDue: "2026-02-15",
  seller: { name: "Acme Corp", address: "123 Main St" },
  buyer:  { name: "Client Inc", address: "456 Oak Ave" },
  items: [
    { name: "Consulting", amount: 10, unit: "hours",
      netPrice: 150, vat: 0, netAmount: 1500, vatAmount: 0, preTaxAmount: 1500 },
  ],
  total: 1500,
};

const compressed = LZString.compressToEncodedURIComponent(
  JSON.stringify(compressKeys(invoice))
);
const url = `https://h1d.github.io/easypdf-lite/?data=${compressed}`;

Only include the fields you need — the app fills in defaults for everything else. The key map is served at /key-map.json and stays in sync with the source automatically. See src/types.ts for the full InvoiceData shape.