README

GST-compliant invoices with HSN/SAC codes and tax breakdowns.

Produces a GST-compliant tax invoice: HSN or SAC per line, taxable value, the correct tax heads for the place of supply, and the invoice total in both figures and words.

One of the CRMLeaf payroll tools. The arithmetic and the dated statutory rate tables live in crmleaf/payroll-core; this package is the thin skin that makes one calculator installable, mountable and embeddable on its own.

Note

A wrong figure or an out-of-date rate is almost always a payroll-core matter, since that is where the tables live. Anything about this tool's routes, views or browser asset belongs here.

Install

Composer - Laravel auto-discovers the service provider, so this is the whole setup:

composer require crmleaf/invoice-generator

npm - the same calculation, re-exported from @crmleaf/payroll-js so you can install this one tool and nothing else:

npm install @crmleaf/invoice-generator

Note

Not on npm yet. The script-tag route below needs no registry and works today. Installing this package straight from git will not resolve @crmleaf/payroll-js, which is not published yet either.

A plain script tag - no build step, no bundler, no server. Build the browser bundle once and serve the file yourself:

<script src="/js/payroll.min.js"></script>
<script>
const result = CrmleafPayroll.invoice({
  invoiceNumber: "INV-2025-0001",
  invoiceDate: "2025-08-01",
  sellerState: "Karnataka",
  buyerState: "Maharashtra",
  items: [{"description":"Payroll processing services","sac":"998221","quantity":1,"rate":50000,"gstRate":18}],
});
console.log(result.explain);
</script>

payroll.min.js is the single-file browser build. Get it by running npm run build in @crmleaf/payroll-js and copying dist/payroll.min.js into whatever your site serves as static assets.

A hosted CDN build is coming soon, which will reduce this to a single URL. Serving the file yourself works today and keeps working afterwards - it is the only option that needs no third-party request, so plenty of projects will want to stay on it.

See it working first

demo/index.html in this repository is a working copy of Invoice Generator in one file: the form, the calculation and the working, with no build step and no server. Drop payroll.min.js beside it and open it from disk.

cp /path/to/payroll-js/dist/payroll.min.js demo/
open demo/index.html

Nothing on that page reaches the network, which is the point: it is a calculator people paste salary figures into.

Use it

Plain PHP, no framework and no container:

use Crmleaf\Payroll\Calculators\InvoiceGenerator;
use Crmleaf\Payroll\Money;

$result = (new InvoiceGenerator())->calculate(
    invoiceNumber: 'INV-2025-0001',
    invoiceDate: new \DateTimeImmutable('2025-08-01'),
    sellerState: 'Karnataka',
    buyerState: 'Maharashtra',
    items: [
            [
                'description' => 'Payroll processing services',
                'sac' => '998221',
                'quantity' => 1,
                'rate' => 50000,
                'gstRate' => 18,
            ],
        ],
);

echo $result->explain();      // the formula with the real operands in it
echo $result->workings();     // every step, one per line, with its citation
print_r($result->toArray());  // snake_case, ready for JSON

Laravel - resolve it from the container, or type-hint it anywhere:

use Crmleaf\Payroll\Calculators\InvoiceGenerator;

public function show(InvoiceGenerator $calculator)
{
    return $calculator->calculate(
        invoiceNumber: 'INV-2025-0001',
        invoiceDate: new \DateTimeImmutable('2025-08-01'),
        sellerState: 'Karnataka',
        buyerState: 'Maharashtra',
        items: [
                [
                    'description' => 'Payroll processing services',
                    'sac' => '998221',
                    'quantity' => 1,
                    'rate' => 50000,
                    'gstRate' => 18,
                ],
            ],
    )->toArray();
}

Blade - one component, no controller:

<x-crmleaf::invoice-generator />

HTTP - off by default. Publish the config and turn the route on:

php artisan vendor:publish --tag=invoice-generator-config

// config/invoice-generator.php
'route' => ['enabled' => true, 'prefix' => 'tools'],

curl -X POST https://example.test/tools/invoice-generator \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json' \
  -d '{"invoice_number":"INV-2025-0001","invoice_date":"2025-08-01","seller_state":"Karnataka","buyer_state":"Maharashtra","items":[{"description":"Payroll processing services","sac":"998221","quantity":1,"rate":50000,"gstRate":18}]}'

The JSON response carries the figures, the working and the statutory citations:

{
  "tool": "invoice-generator",
  "data": { "…": "every figure, snake_case, with a *_formatted twin" },
  "explain": "the formula with the real operands substituted",
  "working": [{ "label": "…", "amount": 0, "formula": "…", "citation": "…" }],
  "citations": ["…"]
}

JavaScript:

import { invoice } from '@crmleaf/invoice-generator';

const result = invoice({
  invoiceNumber: "INV-2025-0001",
  invoiceDate: "2025-08-01",
  sellerState: "Karnataka",
  buyerState: "Maharashtra",
  items: [{"description":"Payroll processing services","sac":"998221","quantity":1,"rate":50000,"gstRate":18}],
});

Documents render inside your application

This tool writes a PDF file, which means it needs a server. Rendering happens in your application, against your published config, and the bytes never leave your infrastructure - there is no hosted document service and therefore no credential for a browser to carry.

composer require dompdf/dompdf
php artisan vendor:publish --tag=invoice-generator-config   # company name, address, GSTIN, logo

use Crmleaf\Payroll\Tools\InvoiceGenerator\Documents\InvoiceGeneratorDocument;

return app(InvoiceGeneratorDocument::class)->download($result, 'invoice-generator.pdf');

Add format=pdf to the HTTP request and the route returns the file directly.

Inputs

Field	Type	Required	Default	Notes
`invoice_number`	string	Yes	`"INV-2025-0001"`	Rule 46(b) caps this at sixteen characters and requires it to be unique within the financial year.
`invoice_date`	date (YYYY-MM-DD)	Yes	`"2025-08-01"`
`seller_state`	string	Yes	`"Karnataka"`
`buyer_state`	string	Yes	`"Maharashtra"`	Different from the seller state means IGST; the same state means CGST plus SGST.
`buyer_gstin`	string	No	`"27AAACT2727Q1ZW"`
`items`	array or JSON	Yes	`[{"description":"Payroll processing services","sac":"998221","quantity":1,"rate":50000,"gstRate":18}]`	One object per line: description, hsn or sac, quantity, rate and gstRate.
`reverse_charge`	boolean	No	`false`
`as_of`	date (YYYY-MM-DD)	No	-

Optional fields you leave out are omitted from the call entirely, so the calculator's own documented defaults apply.

Every figure here rests on a statutory rate, so the call takes as_of. Set it and the calculation runs on the rates in force on that date, which is what makes a prior year recomputable rather than merely rememberable.

Statutory basis

CGST Rules 2017, rules 46 and 47 - the particulars a tax invoice must carry - with the IGST versus CGST/SGST split decided by the place of supply under sections 10 and 12 of the IGST Act 2017.

Rates are data, not code: they live in dated tables with a cited source in crmleaf/payroll-core, so a rate change is a new dated entry rather than an edit to a constant.

Important

This package implements our reading of the applicable statutes and is provided without warranty. It is a calculation library, not tax advice. Verify against your own compliance obligations before relying on the output for statutory filing.

Publishing

Tag	Publishes
`invoice-generator-config`	`config/invoice-generator.php`
`invoice-generator-views`	`resources/views/vendor/invoice-generator`
`invoice-generator-assets`	`public/vendor/invoice-generator`

crmleaf / invoice-generator

Maintainers

Package info

Statistics

Security