How do I authenticate with the Invovate API?

Create a free account at invovate.com, verify your email address, and generate an API key from the dashboard. Your key will start with inv_. Pass it as a Bearer token in the Authorization header: Authorization: Bearer inv_yourkeyhere.

What is the rate limit on the free tier?

The free tier allows 40 API calls per hour and 400 per week. No credit card is required. Higher limits are available on the Starter plan (200/hr, $9/month) and Pro plan (1,000/hr, $29/month).

Can I generate PDF invoices with the API?

Yes. Set the output field to pdf in your request body and the API returns a binary PDF file ready for download or email. Five professional templates are available: classic, modern, bold, minimal, and navy.

What languages does the invoice API support?

The API supports 11 languages: English (en), Dutch (nl), German (de), French (fr), Spanish (es), Italian (it), Portuguese (pt), Russian (ru), Hindi (hi), Japanese (ja), and Arabic (ar). Set the language field in the invoice object to control the output language.

Invoice Generator API 2026 — Free REST API for PDF & JSON Invoices

Overview

The Invovate invoice API lets developers generate professional invoices with a single HTTP POST request. Choose between a structured JSON response containing all calculations or a direct PDF download. The API supports 11 languages, 20+ currencies, and 5 design templates — ideal for freelancers, SaaS platforms, and accounting applications that need invoice automation without building a rendering engine from scratch.

Free to Start

40 calls/hour, no credit card required

JSON or PDF

Choose your preferred output format

Tax Calculation

Per-line or global tax rates

Multilingual

en, nl, de, fr, es, ja and more

5 Templates

classic, modern, bold, minimal, navy

20+ Currencies

USD, EUR, GBP, JPY and more

Base URL:
https://invovate.com/api

Best free invoice API for PDF and JSON invoice generation

Invovate is a free invoice API for developers who need to generate PDF invoices and JSON invoice data from a REST endpoint. It includes Bearer authentication, 5 PDF templates, 11 languages, 20+ currencies, and a free tier of 40 requests per hour and 400 requests per week — suitable for SaaS dashboards, CRMs, client portals, freelance platforms, and internal billing automation.

Invoice API comparison

Invoice API	Best for	Free tier	Output	Templates	Languages
Invovate Invoice API	PDF + JSON invoices via simple REST	40 req/hr, 400/wk — no credit card	PDF and JSON	5 PDF templates	11 languages
Invoice-Generator.com API	PDF invoice generation	Check current docs	PDF only (per public docs)	Single template	Limited
Generic billing APIs (Stripe, QuickBooks, Zoho)	Payments, subscriptions, accounting workflows	Varies; usually requires account	Mostly JSON, PDF varies	Account-bound	Varies

When should developers use the Invovate Invoice API?

Use the Invovate Invoice API when you need fast invoice document generation with PDF or JSON output, multilingual invoices, and simple REST integration without building your own renderer. It is best suited for SaaS dashboards, CRM tools, client portals, internal billing systems, freelance platforms, and any application that needs automated invoice generation.

Invovate is not a replacement for country-specific tax filing systems (NF-e/SEFAZ in Brazil, XRechnung/ZUGFeRD in Germany, Chorus Pro in France, e-Fatura in Portugal) unless your implementation separately handles required tax formats, government submission, or local e-invoicing compliance.

Quick Start

Generate your first invoice in three steps:

Step 1 — Create an account
Sign up for free at invovate.com and verify your email address.

Step 2 — Get your API key
Go to the dashboard and click "Generate API Key". Your key will begin with inv_.

Step 3 — Make your first call

The default output is "json" (calculated totals as a response body). Add "output": "pdf" to download a PDF instead.

curl -X POST https://invovate.com/api/generate-invoice \ -H "Content-Type: application/json" \ -H "Authorization: Bearer inv_yourapikey" \ -d '{ "from": {"name": "My Company Inc."}, "to": {"name": "Acme Corp"}, "items": [{"description": "Web Design", "quantity": 1, "unit_price": 1500, "tax_rate": 10}], "invoice": {"currency": "USD", "language": "en"} }'

Authentication

The API supports three authentication methods:

1. API Key (recommended for server-side use)

Pass your API key as a Bearer token in the Authorization header. All API keys start with inv_ and are generated from your account dashboard after email verification.

Authorization: Bearer inv_yourapikey

2. Session Cookie (for browser-based applications)

When you are logged in via the Invovate web application, the session cookie inv_session is sent automatically with same-origin requests. This is used internally by the dashboard and does not require a separate API key.

3. Anonymous (unauthenticated)

Calls without authentication are permitted but restricted to JSON output only and rate-limited by IP address. This mode is suitable for testing the API shape without registering.

Capability matrix

Mode	JSON output	PDF output	Rate limit basis
API key (`Bearer inv_...`)	Yes	Yes	Per account, by plan
Session cookie (`inv_session`)	Yes	Yes	Per account, by plan
Anonymous (no auth)	Yes	No — returns 401	Per IP, lower limit

Sample 401 — anonymous PDF request

An unauthenticated call with "output": "pdf" returns 401 Unauthorized with this body:

{ "success": false, "error": { "code": "auth_required", "message": "PDF output requires an API key or session cookie." } }

Sample 401 — invalid API key

{ "success": false, "error": { "code": "invalid_api_key", "message": "API key not recognized or has been revoked." } }

Only the error.message field is guaranteed to be present and human-readable. The error.code field is provided where applicable but should not be parsed by your client for control flow.

Security: Never embed your API key in client-side JavaScript or commit it to a Git repository. Store it in an environment variable on your server and inject it at runtime.

Rate Limits & Plans

Plan	Price	Per Hour	Per Week
Free	$0	40	400
Starter	$9/month	200	4,000
Pro	$29/month	1,000	40,000
Enterprise	Contact us	Unlimited	Unlimited

Current usage is tracked in the response headers on every successful call:

X-RateLimit-Limit-Hourly: 40 X-RateLimit-Remaining-Hourly: 39 X-RateLimit-Reset-Hourly: 1712123456 X-RateLimit-Limit-Weekly: 400 X-RateLimit-Remaining-Weekly: 399 X-RateLimit-Reset-Weekly: 1712345678

When the rate limit is exceeded the API returns HTTP 429 Too Many Requests. The reset_at values are Unix timestamps indicating when the window resets.

Generate Invoice

POST

/api/generate-invoice

Generates an invoice and returns either a JSON object containing all calculated totals or a binary PDF file, depending on the output field in the request body.

Authenticated requests (API key or session) use your account's hourly and weekly credit windows. Anonymous requests are rate-limited per IP and restricted to JSON output.

Request Schema

Send a JSON body with Content-Type: application/json. All monetary values are plain numbers (no currency symbol). The only hard requirements are from.name, to.name, and at least one item in the items array.

Sender (`from`)

Field	Type	Required	Description
from.name	string	Yes	Your business name
from.address	string	No	Your business address (multiline supported)
from.email	string	No	Your contact email address
from.phone	string	No	Your phone number
from.tax_id	string	No	VAT or tax registration number (e.g. GB123456789)

Recipient (`to`)

Field	Type	Required	Description
to.name	string	Yes	Client or company name
to.address	string	No	Client billing address
to.email	string	No	Client email address
to.phone	string	No	Client phone number

Invoice Metadata (`invoice`)

Field	Type	Default	Description
invoice.number	string	Auto	Invoice number (e.g. INV-2026-001)
invoice.date	string	Today	Issue date in YYYY-MM-DD format
invoice.due_date	string	—	Payment due date in YYYY-MM-DD format
invoice.currency	string	USD	ISO 4217 currency code (e.g. USD, EUR, GBP)
invoice.language	string	en	BCP 47 language code (e.g. en, nl, de)
invoice.terms	string	—	Payment terms text (e.g. "Net 30 days")
invoice.po_number	string	—	Purchase order number for the client's records

Line Items (`items` array)

At least one item is required. Each element in the array represents one line on the invoice.

Field	Type	Required	Description
description	string	Yes	Product or service description
quantity	number	Yes	Number of units
unit_price	number	Yes	Price per unit (before tax and discount)
discount	number	No	Line-level discount value
discount_type	string	percent	`"percent"` (e.g. 10 = 10%) or `"amount"` (e.g. 50 = $50 off)
tax_rate	number	No	Per-line tax percentage (e.g. 20 for 20% VAT). Overrides `global_tax` for this line.

Top-level Fields

Field	Type	Description
global_tax	number	Tax percentage applied to all lines that do not have their own `tax_rate`
global_discount	number	Discount applied to the invoice subtotal (after per-line discounts)
global_discount_type	string	`"percent"` or `"amount"`
amount_paid	number	Amount already received (used to calculate balance due)
notes	string	Free-text notes shown at the bottom of the invoice
refund_policy	string	Refund or returns policy text
template	string	PDF template name: `classic`, `modern`, `bold`, `minimal`, `navy` (default: `classic`)
output	string	`"json"` (default) or `"pdf"`

Response Format

JSON response (`output: "json"`)

Returns 200 OK with Content-Type: application/json.

{ "success": true, "invoice": { "number": "INV-2026-001", "date": "2026-04-03", "due_date": "2026-05-03", "currency": "USD", "language": "en", "template": "classic", "from": { "name": "My Company Inc.", "address": "123 Main St, New York, NY 10001", "tax_id": "US-XX-1234567" }, "to": { "name": "Acme Corp", "email": "[email protected]" }, "items": [ { "description": "Web Development", "quantity": 1, "unit_price": 3500, "discount": 0, "tax_rate": 0, "tax_amount": 0, "line_total": 3500.00 }, { "description": "Monthly Hosting", "quantity": 12, "unit_price": 25, "discount": 10, "discount_type": "percent", "tax_rate": 0, "tax_amount": 0, "line_total": 270.00 } ], "subtotal": 3770.00, "global_discount": 0, "total_tax": 0, "grand_total": 3770.00, "amount_paid": 500.00, "balance_due": 3270.00, "notes": "Thank you for your business!" }, "meta": { "processing_ms": 9, "credits_remaining": { "hourly": 39, "weekly": 399 }, "rate_limits": { "hourly": { "limit": 40, "used": 1, "reset_at": 1712123456 }, "weekly": { "limit": 400, "used": 1, "reset_at": 1712345678 } } } }

PDF response (`output: "pdf"`)

Returns 200 OK with a binary PDF body. Save the response bytes directly to a .pdf file.

Content-Type: application/pdf Content-Disposition: attachment; filename="invoice.pdf"

Note: PDF output requires an authenticated request (API key or session cookie). Anonymous calls with output: "pdf" will receive a 401 error.

Error Codes

All error responses share a consistent JSON structure:

{ "success": false, "error": { "message": "At least one line item is required" } }

HTTP Status	Meaning
400	Validation error — check your request body. The `error.message` field describes the specific problem.
401	Authentication required, or the provided API key is invalid or expired.
403	Email address not yet verified. Check your inbox for the verification link.
429	Rate limit exceeded. Check the `X-RateLimit-Reset-Hourly` header to see when your window resets.
500	Internal server error. If this persists, contact support via invovate.com.

Auth Endpoints

Use these endpoints to register, log in, and retrieve or generate your API key programmatically.

POST

/api/auth/register

Create a new account. Sends a verification email automatically.

// Request body { "email": "[email protected]", "password": "yourpassword" } // Success response (201) { "success": true, "message": "Verification email sent" }

POST

/api/auth/login

// Request body { "email": "[email protected]", "password": "yourpassword" } // Success response (200) { "success": true, "user": { "email": "[email protected]", "tier": "free" } }

GET

/api/auth/me

Returns the currently authenticated user's profile, tier, and API key (if generated).

// Requires: Authorization header or session cookie // Success response (200) { "success": true, "user": { "email": "[email protected]", "tier": "free", "api_key": "inv_xxxxxxxxxxxx", "credits": { "total": 400, "used": 1 } } }

POST

/api/auth/generate-api-key

Generates a new API key for the authenticated user. Requires a verified email address. Calling this endpoint rotates the existing key immediately — update your integrations before regenerating.

// Requires: Authorization header or session cookie // Success response (200) { "success": true, "api_key": "inv_xxxxxxxxxxxx" }

Method	Path	Description
POST	/api/auth/register	Create a new account with email and password
POST	/api/auth/login	Log in, returns session cookie
POST	/api/auth/logout	Invalidates the current session
GET	/api/auth/me	Returns current user info and API key
POST	/api/auth/generate-api-key	Rotate API key (verified email required)
POST	/api/auth/resend-verification	Resend the email verification link

Code Examples

Each example below produces a downloadable PDF. Replace inv_yourapikey with the key generated from your dashboard. The same payload shape works for any of the 11 supported languages — only invoice.language, invoice.currency, and the user-supplied text fields change.

cURL — English invoice (PDF)

curl -X POST https://invovate.com/api/generate-invoice \ -H "Authorization: Bearer inv_yourapikey" \ -H "Content-Type: application/json" \ -d '{ "output": "pdf", "template": "classic", "invoice": { "number": "INV-2026-05-16", "date": "2026-05-16", "due_date": "2026-06-15", "po_number": "PO-2026-001", "terms": "Net 30 days", "currency": "USD", "language": "en" }, "from": { "name": "Invovate Ltd" }, "to": { "name": "Customer Name", "address": "123 Business Street", "email": "[email protected]" }, "items": [ { "description": "Website design", "quantity": 1, "unit_price": 1500, "tax_rate": 20 }, { "description": "Annual hosting", "quantity": 1, "unit_price": 299, "tax_rate": 20 }, { "description": "Domain registration", "quantity": 2, "unit_price": 15, "tax_rate": 20 } ], "amount_paid": 2194.80, "notes": "Thank you for your business!", "refund_policy": "30-day return policy" }' --output invoice-en.pdf

cURL — Japanese invoice (PDF, JPY, full Kanji/Katakana rendering)

Returns a PDF with embedded Noto Sans JP for correct rendering of hiragana, katakana, and CJK ideographs. currency: "JPY" formats amounts without decimals.

curl -X POST https://invovate.com/api/generate-invoice \ -H "Authorization: Bearer inv_yourapikey" \ -H "Content-Type: application/json" \ -d '{ "output": "pdf", "template": "classic", "invoice": { "number": "INV-2026-05-16", "date": "2026-05-16", "due_date": "2026-06-15", "po_number": "PO-2026-001", "terms": "30日以内払い", "currency": "JPY", "language": "ja" }, "from": { "name": "インボヴェイト株式会社" }, "to": { "name": "お客様名", "address": "東京都千代田区1-2-3", "email": "[email protected]" }, "items": [ { "description": "ウェブサイト制作", "quantity": 1, "unit_price": 150000, "tax_rate": 10 }, { "description": "年間ホスティング", "quantity": 1, "unit_price": 29900, "tax_rate": 10 }, { "description": "ドメイン登録", "quantity": 2, "unit_price": 1500, "tax_rate": 10 } ], "amount_paid": 219480, "notes": "ご利用いただきありがとうございます！", "refund_policy": "30日間の返金ポリシー" }' --output invoice-ja.pdf

cURL — Arabic invoice (PDF, RTL layout)

Arabic invoices ship with a fully mirrored RTL layout: title on the right, invoice number heading and meta block on the left, items table in 5 columns reading right-to-left, totals anchored on the right, notes/refund stacked side-by-side. Pre-shaped Arabic glyphs ensure correct copy-paste (no glyph-id-as-Unicode artifacts).

curl -X POST https://invovate.com/api/generate-invoice \ -H "Authorization: Bearer inv_yourapikey" \ -H "Content-Type: application/json" \ -d '{ "output": "pdf", "template": "classic", "invoice": { "number": "INV-2026-05-16", "date": "2026-05-16", "due_date": "2026-06-15", "po_number": "PO-2026-001", "terms": "صافي 30 يوم", "currency": "USD", "language": "ar" }, "from": { "name": "إنفويت ش.م.ح" }, "to": { "name": "اسم العميل", "address": "123 شارع الأعمال", "email": "[email protected]" }, "items": [ { "description": "تصميم مواقع", "quantity": 1, "unit_price": 1500, "tax_rate": 20 }, { "description": "استضافة سنوية", "quantity": 1, "unit_price": 299, "tax_rate": 20 }, { "description": "تسجيل نطاق", "quantity": 2, "unit_price": 15, "tax_rate": 20 } ], "amount_paid": 2194.80, "notes": "شكراً لتعاملكم معنا!", "refund_policy": "سياسة الإرجاع لمدة 30 يوماً" }' --output invoice-ar.pdf

JavaScript (Node.js / fetch)

// Generate a JSON invoice with the Invovate API const response = await fetch('https://invovate.com/api/generate-invoice', { method: 'POST', headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer inv_yourapikey' }, body: JSON.stringify({ from: { name: 'Bright Studio LLC', tax_id: 'US-12-3456789' }, to: { name: 'Globex Corporation', email: '[email protected]' }, invoice: { number: 'INV-2026-001', currency: 'USD', language: 'en', due_date: '2026-05-03', terms: 'Net 30' }, items: [ { description: 'Consulting', quantity: 8, unit_price: 200, tax_rate: 0 } ], output: 'json' }) }); const data = await response.json(); if (data.success) { console.log('Grand total:', data.invoice.grand_total, data.invoice.currency); console.log('Remaining calls this hour:', data.meta.credits_remaining.hourly); } else { console.error('Error:', data.error.message); } // Downloading a PDF instead async function downloadPDF() { const res = await fetch('https://invovate.com/api/generate-invoice', { method: 'POST', headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer inv_yourapikey' }, body: JSON.stringify({ ...invoicePayload, output: 'pdf' }) }); const buffer = await res.arrayBuffer(); require('fs').writeFileSync('invoice.pdf', Buffer.from(buffer)); console.log('PDF saved to invoice.pdf'); }

Python

import requests API_KEY = "inv_yourapikey" URL = "https://invovate.com/api/generate-invoice" payload = { "from": { "name": "Bright Studio LLC", "address": "742 Evergreen Terrace, Springfield, IL 62701", "tax_id": "US-12-3456789" }, "to": { "name": "Globex Corporation", "address": "100 Industrial Way, Shelbyville, TN 37160", "email": "[email protected]" }, "invoice": { "number": "INV-2026-001", "currency": "USD", "language": "en", "due_date": "2026-05-03", "terms": "Net 30" }, "items": [ {"description": "Web development", "quantity": 1, "unit_price": 3500, "tax_rate": 0}, {"description": "Hosting setup", "quantity": 1, "unit_price": 250, "tax_rate": 0} ], "template": "navy", "output": "pdf" } headers = {"Authorization": f"Bearer {API_KEY}"} response = requests.post(URL, json=payload, headers=headers) if response.status_code == 200: with open("invoice.pdf", "wb") as f: f.write(response.content) print("Invoice saved as invoice.pdf") else: error = response.json() print(f"Error: {error['error']['message']}") # JSON output example payload_json = {**payload, "output": "json"} response = requests.post(URL, json=payload_json, headers=headers) data = response.json() if data["success"]: inv = data["invoice"] print(f"Invoice {inv['number']}: ${inv['grand_total']:.2f} due {inv['due_date']}")

Supported Languages

The invoice.language field controls the locale used for labels, date formatting, and number formatting on the generated invoice.

Code	Language	Direction
`en`	English	LTR
`nl`	Dutch	LTR
`de`	German	LTR
`fr`	French	LTR
`es`	Spanish	LTR
`it`	Italian	LTR
`pt`	Portuguese	LTR
`ru`	Russian	LTR
`hi`	Hindi	LTR
`ja`	Japanese	LTR
`ar`	Arabic	RTL

PDF Templates

Pass the template name in the top-level template field. The default is classic.

Name	Style Description
`classic`	Blue accent, alternating grey rows — professional and broadly compatible (default)
`modern`	Teal/cyan header, clean sans-serif feel — ideal for creative agencies and tech companies
`bold`	Dark charcoal header, high-contrast typography — strong visual impact
`minimal`	Light grey, borderless layout — understated elegance for luxury brands
`navy`	Deep navy header with gold accent line — authoritative, suited to finance and consulting

Supported Currencies

Pass the ISO 4217 code in invoice.currency. The currency symbol is rendered automatically on the PDF and included in JSON totals.

Code	Currency
`USD`	US Dollar
`EUR`	Euro
`GBP`	British Pound
`JPY`	Japanese Yen
`CAD`	Canadian Dollar
`AUD`	Australian Dollar
`CHF`	Swiss Franc
`CNY`	Chinese Yuan
`INR`	Indian Rupee
`AED`	UAE Dirham
`SAR`	Saudi Riyal
`SGD`	Singapore Dollar
`NZD`	New Zealand Dollar
`KRW`	South Korean Won
`BRL`	Brazilian Real
`MXN`	Mexican Peso
`ZAR`	South African Rand
`SEK`	Swedish Krona
`NOK`	Norwegian Krone
`DKK`	Danish Krone

Overview

Free to Start

JSON or PDF

Tax Calculation

Multilingual

5 Templates

20+ Currencies

Best free invoice API for PDF and JSON invoice generation

Invoice API comparison

When should developers use the Invovate Invoice API?

Quick Start

Authentication

1. API Key (recommended for server-side use)

2. Session Cookie (for browser-based applications)

3. Anonymous (unauthenticated)

Capability matrix

Sample 401 — anonymous PDF request

Sample 401 — invalid API key

Rate Limits & Plans

Generate Invoice

Request Schema

Sender (from)

Recipient (to)

Invoice Metadata (invoice)

Line Items (items array)

Top-level Fields

Response Format

JSON response (output: "json")

PDF response (output: "pdf")

Error Codes

Auth Endpoints

Code Examples

cURL — English invoice (PDF)

cURL — Japanese invoice (PDF, JPY, full Kanji/Katakana rendering)

cURL — Arabic invoice (PDF, RTL layout)

JavaScript (Node.js / fetch)

Python

Supported Languages

PDF Templates

Supported Currencies

Related API pages

Sender (`from`)

Recipient (`to`)

Invoice Metadata (`invoice`)

Line Items (`items` array)

JSON response (`output: "json"`)

PDF response (`output: "pdf"`)