GST invoice API

Make a GST tax invoice

POST/v1/invoice

Fields: number (required, up to 16 letters, digits, - and /), date and due_date (YYYY-MM-DD, date defaults to today), title (default Tax Invoice), place_of_supply (state code, name or GST code; defaults to the buyer's state from the GSTIN or state), reverse_charge, seller and buyer (name, address, gstin, state, phone, email; the seller's GSTIN is required), ship_to, items (description, hsn, quantity (default 1), unit (default Nos), rate before tax, discount as an amount, gst_rate in percent), bank (name, account, ifsc, branch, holder), upi, notes and terms. Unknown fields are refused, so a misspelt field is caught. format=json returns the worked-out invoice instead of a document; format=png the first page as a picture.

Send: The invoice as JSON, up to 256 KB.

The answer returns the PDF itself; errors are JSON as everywhere else.

What you send here is never written to the log, and the answer is not cached.

curl -H "Content-Type: application/json" --data @invoice.json -o invoice.pdf "https://api.dharun.dev/v1/invoice"

const response = await fetch("https://api.dharun.dev/v1/invoice", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify(invoice),
});
if (!response.ok) throw new Error((await response.json()).error.message);
const pdf = await response.blob();

import json, requests

invoice = json.load(open("invoice.json"))
response = requests.post("https://api.dharun.dev/v1/invoice", json=invoice, timeout=60)
if not response.ok:
    raise RuntimeError(response.json()["error"]["message"])
open("invoice.pdf", "wb").write(response.content)

invoice.json

{
  "number": "INV-2026-0042",
  "date": "2026-10-14",
  "seller": {"name": "Sri Murugan Stores", "address": "12 Car Street, Namakkal 637001", "gstin": "33AABCS1429B1Z1"},
  "buyer": {"name": "Kaveri Traders", "address": "4 MG Road, Bengaluru 560001", "gstin": "29AAACK6812C1ZS"},
  "items": [
    {"description": "Basmati rice, 25 kg bag", "hsn": "1006", "quantity": 4, "unit": "Bag", "rate": 2150, "gst_rate": 5},
    {"description": "Steel tiffin box", "hsn": "7323", "quantity": 10, "rate": 349.5, "discount": 120, "gst_rate": 18}
  ],
  "bank": {"name": "State Bank of India", "account": "12345678901", "ifsc": "SBIN0000001", "holder": "Sri Murugan Stores"},
  "upi": "srimurugan@okaxis",
  "terms": "Goods once sold will not be taken back."
}