Integrate complete e-invoicing service with your software

Picture showing transformation api cloud engine e-invoices online data to e-invoice
  • E-invoice creation & management
  • Direct delivery to clients and tax authorities
  • Receiving directly to our service
  • Store e-invoices in our cloud archive

Implement our API to integration with your software

Full e-invoicing solution with 1 API key

Our API key will provide your software with our full e-invoicing solution, flawlessly integrated.

Skip all development of e-invoicing

With our e-invoice creation, delivery and storage system & our UI you can skip the complex development and testing period to implement e-invoicing into your software.

Possibility for fully automated e-invoicing

You can fully automate the e-invoicing process, from e-invoice creation to delivery and storage, directly from your software. (Additional development & service.)

Ensures tax and legal compliance at all times

We take care of compliance with all future legislation changes so you can forget about them completely - forever.

Full e-invoicing service with an API

UI developed for people dealing with invoices in their day-to-day

  • Easy creating, editing, canceling and duplicating
  • Information auto-fill, automatic calculations and easy article import
  • One-click bulk sending
  • Easily give out credit notes to customers
  • Personalization with logo, signature and stamp to match your branding
  • Clear overview of the status of your e-invoices. Received, accepted, rejected or other.

Try out these features in our demo!

Domestic and international delivery

  • Delivery to any tax authority in your country, and internationally to companies via the Peppol network
  • Add attachments to any e-invoices

Store e-invoices in our secure archive

  • Legally compliant archive, which replaces physical archive and stores your e-invoices for 10+ years

Connected to your software in 1 day

We developed APIs that are extremely easy to integrate. See how below.

How to start?

By integrating our API, you spend a fraction of the cost and time neccessary to develop the full invoicing/e-invoicing/fiscalization functionality.

I am integrating for invoicing in my company

You are integrating as the internal IT department to provide e-invoicing for the software used for your company.


Get a ConnectionKey

Someone from your company should provide you with the Connection Key over the email.

If not, see this page here.


Integrate our APIs

Following the instructions, integrate our integration APIs and test the solution.

Integration iscomplete!

Set up the creation/sending flow as you like.

Congratulations, your software now has a complete e-invoicing solution!

I am integrating as an ISV (independent software vendor)

You are integrating as a software vendor, to provide e-invoicing in your software to your clients.


Register for free

When registering, choose to register your company as an Integrator.


Integrate our APIs

Following the instructions, implement our integration APIs and test the solution.


Add your customers

Add your customers manually or via API and get connection keys for them.

Integration iscomplete!

Set up the creation/sending flow as you like.

Congratulations, your software is now connected to complete e-invoicing software!

Quick and easy integration

infographics showing transformation api data to e-invoice e-invoices online

How does it work?

  1. Invoice data is input directly into the e-Invoices Online web app or input into your software and sent to our cloud in .JSON form with 1 simple REST API.
  2. An e-invoice will appear in our service. The e-invoice can be managed and prepared for sending.
  3. It is then sent & delivered to the tax authority portal, then downloaded back to your software.
  4. E-invoices are safely archived in our legal archive for at least 10 years.*

*If you require e-invoicing ability for your software, but want to use your UI and storage, consider using the Transformation option.

Save months of development time

Use cases

Invoicing software

You have put a great deal of time and effort into developing your invoicing software and building a customer base. Now, there is a new government-imposed e-invoicing requirement that would take you more time and effort to develop. Save your time and money for more important matters, and let us provide you with the e-invoicing component you’re missing.

DMS or EDI software

You provide a comprehensive program that has a large overlap with the requirements for e-invoicing softwares. The document exchange and archiving are key aspects to both services. You likely have clients that would benefit greatly from e-invoicing. So rather than them seeking this service elsewhere, upgrade your program by adding our e-invoicing component to your existing infrastructure.

Developing your own software

You are looking to develop a service/product that includes e-invoicing, but wish to maintain full control of your customers’ experience throughout your service. Instead of redirecting your clients to an external e-invoicing service, the Transformer package allows you to use our service as a hidden partner. Your software can rely on our service, all while never being seen by the customer.

Accounting software

You provide a complete software for accountants, but your software lacks e-invoicing ability. Using our transformation APIs, you can keep focusing on providing the best solution for accountants, and leave the e-invoicing legislation and data transformation to us. Integrate in just days instead of a lengthy development cycle.


One time set-up fee + end-user package.

RSD 11.710 /god.
1171 RSD 976 /mes.
EUR 1000 /one time set-up fee
naplaćuje se godišnje
+ end-user package paid monthly

Integrate full e-invoicing service


By integrating you:

  • Connect your software to e-invoicing
  • Create & manage e-invoices in our service
  • Instantly deliver to tax portals
  • Receive e-invoices directly to our service
  • Archive e-invoices


Each end-user that uses our service through your integration pays a PRO. or BUSINESS package.

PROFESSIONAL: 25 eur/mo. or BUSINESS: 50 eur/mo. Learn more about end-user packages.

An end-user is a person using our service for the purpose of invoicing for their company.

Example for integrating for invoicing in your company: You, as an integrator pay the set-up fee. You also pay for an end-user package, since you are using our service as an end-user.
Example for ISV: You, as an integrator, pay the set-up fee. Your clients that have accounts in our service pay the end-user package price.

Start with integration Payment is required after the integration is complete.

Integration is a service for any software company that needs e-invoicing or that wants to connect their software to a comprehensive e-invoicing solution. It allows them to get a complete e-invoicing solution, without having to develop it themselves. We offer creation in our UI, delivery to government portals and internationally, e-invoice reception and archiving.

Data from your software is sent in .JSON form to our software. Our cloud engine, creates an e-invoice which will appear in our service. The e-invoice can then be managed, sent and archived in our solution. It can also be downloaded back into your ERP. The e-invoices sent to you/your clients will appear in our service.

We made APIs so simple, an experienced developer should be able to complete the integration in 1 day.

As an ISV integrator you only pay the 1000 EUR integration fee. The package price is payed by your (& our) end-users.

Once the integration is completed, you can test it and see if you like it, We will only charge you once the integration is complete and you are totally satisfied.