PDF Invoice Generator - SimpleWebAPIs

Overview

The PDF Invoice Generator creates professional PDF invoices from structured JSON data. Include seller and customer addresses, line items with prices and quantities, custom dates, and comments.

Endpoint

POST /api/invoice

Request Body

Field	Type	Required	Description
invoiceNumber	string	Yes	Unique invoice number
issueDate	string	Yes	Date the invoice was issued (ISO 8601)
dueDate	string	Yes	Payment due date (ISO 8601)
seller	object	Yes	Seller information (name, addressLines, email, phone)
customer	object	Yes	Customer information (same fields as seller)
items	array	Yes	Line items (each: name, price, quantity)
comments	string	No	Optional comments or notes
status	string	No	Invoice status (e.g. "paid", "pending", "overdue")
taxLabel	string	No	Label for the tax line (e.g. "VAT", "GST")
taxRate	decimal	No	Tax rate as a percentage (0–100, e.g. 20 for 20%)
logoUrl	string	No	URL of the logo image (PNG, JPG, SVG) rendered in the header
accentColor	string	No	Hex color for invoice heading and label (default: #3B82F6)
textColor	string	No	Hex color for primary text (default: #1F2937)
mutedTextColor	string	No	Hex color for secondary/muted text (default: #6B7280)
separatorColor	string	No	Hex color for table row borders and address underlines (default: #E5E7EB)
commentsBackgroundColor	string	No	Hex color for the comments box background (default: #F3F4F6)
currency	string	Yes	ISO 4217 currency code (e.g. "USD", "EUR", "GBP")

Example

Generate a PDF invoice:

curl -X POST https://simplewebapis.com/api/invoice \
  -H "Content-Type: application/json" \
  -H "X-Api-Key: swa_your_key" \
  -d '{
    "invoiceNumber": 1001,
    "seller": { "name": "Acme Corp", "addressLines": ["123 Seller St", "San Francisco, CA 94105"], "email": "[email protected]" },
    "customer": { "name": "Globex Inc", "addressLines": ["456 Customer Ave", "New York, NY 10001"], "email": "[email protected]" },
    "items": [
      { "name": "Web Development", "price": 1500.00, "quantity": 1 },
      { "name": "UI Design", "price": 800.00, "quantity": 2 }
    ],
    "comments": "Thank you for your business!",
    "currency": "USD",
    "logoUrl": "https://simplewebapis.com/favicon-32x32.png",
    "accentColor": "#2563EB",
    "separatorColor": "#E5E7EB",
    "commentsBackgroundColor": "#F9FAFB"
  }' --output invoice.pdf

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-Api-Key", "swa_your_key");

var payload = new
{
    invoiceNumber = 1001,
    seller = new { name = "Acme Corp", addressLines = new[] { "123 Seller St", "San Francisco, CA 94105" }, email = "[email protected]" },
    customer = new { name = "Globex Inc", addressLines = new[] { "456 Customer Ave", "New York, NY 10001" }, email = "[email protected]" },
    items = new[]
    {
        new { name = "Web Development", price = 1500.00m, quantity = 1 },
        new { name = "UI Design", price = 800.00m, quantity = 2 }
    },
    comments = "Thank you for your business!",
    Currency = "USD",
    LogoUrl = "https://simplewebapis.com/favicon-32x32.png",
    accentColor = "#2563EB",
    separatorColor = "#E5E7EB",
    commentsBackgroundColor = "#F9FAFB"
};

var json = JsonSerializer.Serialize(payload);
var content = new StringContent(json, Encoding.UTF8, "application/json");

var response = await client.PostAsync(
    "https://simplewebapis.com/api/invoice", content);
var pdfBytes = await response.Content.ReadAsByteArrayAsync();
await File.WriteAllBytesAsync("invoice.pdf", pdfBytes);

$payload = json_encode([
    'invoiceNumber' => 1001,
    'seller' => ['name' => 'Acme Corp', 'addressLines' => ['123 Seller St', 'San Francisco, CA 94105'], 'email' => '[email protected]'],
    'customer' => ['name' => 'Globex Inc', 'addressLines' => ['456 Customer Ave', 'New York, NY 10001'], 'email' => '[email protected]'],
    'items' => [
        ['name' => 'Web Development', 'price' => 1500.00, 'quantity' => 1],
        ['name' => 'UI Design', 'price' => 800.00, 'quantity' => 2],
    ],
    'comments' => 'Thank you for your business!',
    'currency' => 'USD',
    'logoUrl' => 'https://simplewebapis.com/favicon-32x32.png',
    'accentColor' => '#2563EB',
    'separatorColor' => '#E5E7EB',
    'commentsBackgroundColor' => '#F9FAFB',
]);

$ch = curl_init('https://simplewebapis.com/api/invoice');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json',
        'X-Api-Key: swa_your_key',
    ],
    CURLOPT_POSTFIELDS => $payload,
    CURLOPT_RETURNTRANSFER => true,
]);

$pdf = curl_exec($ch);
curl_close($ch);
file_put_contents('invoice.pdf', $pdf);

const response = await fetch('https://simplewebapis.com/api/invoice', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'X-Api-Key': 'swa_your_key',
    },
    body: JSON.stringify({
        invoiceNumber: 1001,
        seller: { name: 'Acme Corp', addressLines: ['123 Seller St', 'San Francisco, CA 94105'], email: '[email protected]' },
        customer: { name: 'Globex Inc', addressLines: ['456 Customer Ave', 'New York, NY 10001'], email: '[email protected]' },
        items: [
            { name: 'Web Development', price: 1500.00, quantity: 1 },
            { name: 'UI Design', price: 800.00, quantity: 2 },
        ],
        comments: 'Thank you for your business!',
        currency: 'USD',
        logoUrl: 'https://simplewebapis.com/favicon-32x32.png',
        accentColor: '#2563EB',
        separatorColor: '#E5E7EB',
        commentsBackgroundColor: '#F9FAFB',
    }),
});

const buffer = await response.arrayBuffer();
const fs = require('fs');
fs.writeFileSync('invoice.pdf', Buffer.from(buffer));

import requests

response = requests.post(
    'https://simplewebapis.com/api/invoice',
    headers={
        'Content-Type': 'application/json',
        'X-Api-Key': 'swa_your_key',
    },
    json={
        'invoiceNumber': 1001,
        'seller': {'name': 'Acme Corp', 'addressLines': ['123 Seller St', 'San Francisco, CA 94105'], 'email': '[email protected]'},
        'customer': {'name': 'Globex Inc', 'addressLines': ['456 Customer Ave', 'New York, NY 10001'], 'email': '[email protected]'},
        'items': [
            {'name': 'Web Development', 'price': 1500.00, 'quantity': 1},
            {'name': 'UI Design', 'price': 800.00, 'quantity': 2},
        ],
        'comments': 'Thank you for your business!',
        'currency': 'USD',
        'logoUrl': 'https://simplewebapis.com/favicon-32x32.png',
        'accentColor': '#2563EB',
        'separatorColor': '#E5E7EB',
        'commentsBackgroundColor': '#F9FAFB',
    },
)

with open('invoice.pdf', 'wb') as f:
    f.write(response.content)

payload := map[string]interface{}{
    "invoiceNumber": 1001,
    "seller": map[string]interface{}{
        "name":  "Acme Corp",
        "addressLines": []string{"123 Seller St", "San Francisco, CA 94105"},
        "email":        "[email protected]",
    },
    "customer": map[string]interface{}{
        "name":  "Globex Inc",
        "addressLines": []string{"456 Customer Ave", "New York, NY 10001"},
        "email":        "[email protected]",
    },
    "items": []map[string]interface{}{
        {"name": "Web Development", "price": 1500.00, "quantity": 1},
        {"name": "UI Design", "price": 800.00, "quantity": 2},
    },
    "comments": "Thank you for your business!",
    "currency": "USD",
    "logoUrl": "https://simplewebapis.com/favicon-32x32.png",
    "accentColor": "#2563EB",
    "separatorColor": "#E5E7EB",
    "commentsBackgroundColor": "#F9FAFB",
}

jsonData, _ := json.Marshal(payload)
req, _ := http.NewRequest("POST", "https://simplewebapis.com/api/invoice",
    bytes.NewBuffer(jsonData))
req.Header.Set("Content-Type", "application/json")
req.Header.Set("X-Api-Key", "swa_your_key")

resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
os.WriteFile("invoice.pdf", body, 0644)

require 'net/http'
require 'json'
require 'uri'

payload = {
  invoiceNumber: 1001,
  seller: { name: 'Acme Corp', addressLines: ['123 Seller St', 'San Francisco, CA 94105'], email: '[email protected]' },
  customer: { name: 'Globex Inc', addressLines: ['456 Customer Ave', 'New York, NY 10001'], email: '[email protected]' },
  items: [
    { name: 'Web Development', price: 1500.00, quantity: 1 },
    { name: 'UI Design', price: 800.00, quantity: 2 },
  ],
  comments: 'Thank you for your business!',
  currency: 'USD',
  logo_url: 'https://simplewebapis.com/favicon-32x32.png',
  accentColor: '#2563EB',
  separatorColor: '#E5E7EB',
  commentsBackgroundColor: '#F9FAFB',
}

uri = URI('https://simplewebapis.com/api/invoice')
req = Net::HTTP::Post.new(uri)
req['Content-Type'] = 'application/json'
req['X-Api-Key'] = 'swa_your_key'
req.body = payload.to_json

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(req) }
File.binwrite('invoice.pdf', response.body)

var payload = """
    {
        "invoiceNumber": 1001,
        "seller": { "name": "Acme Corp", "addressLines": ["123 Seller St", "San Francisco, CA 94105"], "email": "[email protected]" },
        "customer": { "name": "Globex Inc", "addressLines": ["456 Customer Ave", "New York, NY 10001"], "email": "[email protected]" },
        "items": [
            { "name": "Web Development", "price": 1500.00, "quantity": 1 },
            { "name": "UI Design", "price": 800.00, "quantity": 2 }
        ],
        "comments": "Thank you for your business!",
        "currency": "USD",
        "logoUrl": "https://simplewebapis.com/favicon-32x32.png",
        "accentColor": "#2563EB",
        "separatorColor": "#E5E7EB",
        "commentsBackgroundColor": "#F9FAFB"
    }
    """;

var request = HttpRequest.newBuilder()
    .uri(URI.create("https://simplewebapis.com/api/invoice"))
    .header("Content-Type", "application/json")
    .header("X-Api-Key", "swa_your_key")
    .POST(HttpRequest.BodyPublishers.ofString(payload))
    .build();

var response = HttpClient.newHttpClient().send(request,
    HttpResponse.BodyHandlers.ofByteArray());
Files.write(Path.of("invoice.pdf"), response.body());

use serde_json::json;
use std::fs;

let client = reqwest::Client::new();
let payload = json!({
    "invoiceNumber": 1001,
    "seller": { "name": "Acme Corp", "addressLines": ["123 Seller St", "San Francisco, CA 94105"], "email": "[email protected]" },
    "customer": { "name": "Globex Inc", "addressLines": ["456 Customer Ave", "New York, NY 10001"], "email": "[email protected]" },
    "items": [
        { "name": "Web Development", "price": 1500.00, "quantity": 1 },
        { "name": "UI Design", "price": 800.00, "quantity": 2 }
    ],
    "comments": "Thank you for your business!",
    "currency": "USD",
    "logoUrl": "https://simplewebapis.com/favicon-32x32.png",
    "accentColor": "#2563EB",
    "separatorColor": "#E5E7EB",
    "commentsBackgroundColor": "#F9FAFB"
});

let resp = client.post("https://simplewebapis.com/api/invoice")
    .header("Content-Type", "application/json")
    .header("X-Api-Key", "swa_your_key")
    .json(&payload)
    .send()
    .await?;

let bytes = resp.bytes().await?;
fs::write("invoice.pdf", &bytes)?;

The response is a PDF document (Content-Type: application/pdf).

Try it out

Use the Playground to test this API live.