Instead of coding everything from scratch, most companies integrate an invoicing API. But not all APIs are equal. Some only handle the basics; others go deep into compliance, automation, and even embedded finance.
In this guide, we’ll break down:
What is an Invoicing API?
Core Features Every Invoicing API Should Have
Advanced Features That Make the Difference
Why Compliance Features Matter in 2025
How to Choose the Right API for Your Business
What Is an Invoicing API?
Invoicing API lets you and your clients create, send, and manage invoices, lately focused on e-invoices. Instead of manually generating documents, you connect an API to your platform or software that manages your company’s resources and sales.
The invoicing API automatically creates an e-invoice every time a trigger occurs, checks it for compliance, and sends it through an official network (usually Peppol). The government can also review it in real time, but in most cases simply stamps it as additional proof of compliance. When the e-invoice comes to the receiver’s invoicing software, it checks the stamp and compliance of the invoice. When confirmed, it is archived and paid.
Core Invoicing API Features
When comparing APIs, check if they cover the essentials:
Invoice Creation:
Generate e-invoices automatically and in different formats (XML, UBL, Factur-X, Peppol BIS). Keep in mind, that PDFs are not e-invoices.
Recurring Billing:
Automate subscription or retainer invoices.
Multi-Currency Support:
Issue invoices in the currency your clients prefer, or is local currency in the country they operate in.
Basic Reporting:
Pull invoice lists, statuses, and totals for accounting.
Payment Links & QR Codes:
Speed up payments with built-in settlement options.
Local Compliance:
VAT/GST calculation (reverse-charge, intra-EU rules, US sales tax).
Support for government-mandated standards (Peppol, Factur-X, UBL, etc.).
Automatic updates when tax rules change.
Scalability:
Can handle thousands of invoices per minute.
Advanced Features That Make the Difference
The best invoicing APIs go beyond the basics. They are more flexible, usually used by global companies, or platforms that offer or upsell the invoicing feature to their clients. Look for:
Credit Notes: Issue structured credit notes to fix mistakes (legally required in e-invoicing).
Archiving & Audit Trail: Store invoices securely for the legally required period.
White-Label Functionality: Embed invoicing feature inside your platform under your own brand, give it an in-house look (meant for platforms).
Integration with Payment Providers: Connect invoicing directly to payment gateways.
Scalability: Handle thousands or millions of invoices without extra setup.
Multitenancy: Allows multiple users to connect to the API, customize invoices and issue without accessing each others data (meant for platforms).
Global Compliance: If you operate in multiple countries look for a global invoicing API, that way you will be constantly compliant with regulations in countries you operate or expand to, without adding or switching APIs.
Unique traits: Some APIs are created for specific cases, for example companies with cryptocurrency payments.
Why Compliance Features Matter in 2025
Invoicing is no longer just about documents, it’s about tax and e-invoicing compliance. Every year a bigger amount of countries decides to mandate it, since it reduces fraud, gives government in real time view of transactions and automates the process for business, reducing costs and manual mistakes. That’s why:
The EU’s 2030 ViDA regulation will make structured B2B e-invoicing and reporting mandatory for all countries and business in EU.
Countries like France, Germany, and Croatia already announced phased mandates in 2025 with many joining in 2026.
PDF is not an e-invoice and sending it by email won’t be enough. Governments demand machine-readable formats.
How to Choose the Right API for Your Business
When evaluating invoicing APIs, ask:
Does it cover the basics (creation, currencies, branding, recurring billing)?
Does it support compliance in the countries I operate in now and plan to expand into?
Can I integrate it fast, or will it take months of dev work?
Does it help me upsell clients by offering invoicing under my own brand?
All the Features in One Global API
At Space Invoices, we built our API to handle both the basics and advanced compliance features. With us, you can:
Create invoices, credit notes, and recurring billing with ease
Automatically apply tax rules in 70+ countries
White-label invoicing and offer it inside your own platform
Provide payment links, QR codes, and multi-currency support
Stay compliant with EU ViDA and other global mandates
Integrate in less than a week with full developer support
Why juggle multiple tools when one API covers it all?
We’re ready to help you get started.
