Frequently Asked Questions
August 5, 2026•
faq
Simply register to access the step-by-step guide for integration between your software and our platform and see the dashboard with administration module and invoice flow control. Pro tip: Invite your teammates and developers responsible for integration!
1. Successfully test and complete integration of your software with DDD Invoices platform (developers required).
2. Add any legal entities, for whom you are making your software compliant.
3. Fill in your company data and the data of other legal entities (certificates etc.).
4. Switch to production!
Your software will get the ability of compliant invoicing either for your own invoicing or for the users of your software. We can help you with providing the whole invoicing infrastructure for generating tax compliant PDFs, fiscalized (QR codes) invoices and e-invoices, delivery to tax authority portals & clients via e-mail, receiving from tax authority portals, secure web-server and OCR-ing received non-e-Invoices and legal archiving of your invoices in a government approved legal storages. Additionally, we offer the possibility of EU trusted time-stamping and digital signatures.
Please reach out with your requirements about the desired country and use case. Please state the country, type of invoice (B2B, B2C, B2G), cross-border and if it is issued, received invoices or fiscalization only need.
We are connected to a PEPPOL network and are a certified PEPPOL access point.
Our platform is indefinitely expandable, which we can adjust accordingly to make sure the bandwidth is sufficient.
Usually, there is no need for training of your staff. Once the tech team created and tested the integration, your team member (Trustee) uses the Dashboard for overseeing purposes. Developers have access to the integration learning playground inside the dashboard so they can perform all the neccesarry actions. We provide support during the whole integration procedure and afterwards, in case of any questions.
Yes. After the sign-up you will get access to the dashboard with a comprehensive administration module, invoice-flow control module and integration module. In the administration module, you handle all actions regarding the company's data and certificates, in invoice-flow control module you have the overview of successful invoices and invoices with errors, that you can filter and download for later reporting and in integration module the tech team get all the information regarding integration.
In general, you only need to integrate with our platform and send invoice data. We will take care about the rest. Ofcourse, you need to know your requirements and use case. We aim to assist you with that as much as possible with our comprehensive blogs & API playground.
You can do e-invoice, fiscalizated invoice (with a QR code) or just normal .PDFs. Their usage, usually depends of the country's invoicing requirements and company needs.
The template is visible after the registration in the Integration section of the Dashboard.
You can customize our template with your or your clients logos, signatures & stamp.
We can create a custom visualization of the invoice specifically for your needs as a custom work.
Ofcourse. You can add your .PDF visualizations, contracts or other attachments.
We offer PDF creation in English, German, Spanish, Polish, French, Slovenian, Croatian, Serbian, Montenegrin, Italian, Romanian, Dutch, Bosnian, Estonian, Slovakian, Czech and adding new daily. We offer almost every currency available.
Developers prepare a .JSON object with a small and simple set of invoice data and send it to our platform via the REST API. This essential integration can be learned and implemented in one working day. From this data, we generate tax compliant invoice. Then, based on your requirements, we send the invoice to potential clients, tax authorities or simply return you compliant invoice in the API reponse.
Developers can help themself with API documentation outside & much more comprehensive API playground on the Dashboard.
The integration with our platform is probably the most simple on the market. Basic integration can be done in just a couple of hours.
More advanced invoices requirements (storno invoices, proforma invoices, mass API etc.) can be finished in 3-5 additional days.
There is a single API for the global compliance. You only need to integrate once, to cover multiple countries and easier expansion.
You only have one account. Tech team is integrating & testing the integration with the Integration API key, used only for integration between your software and our platform.
When you want to start sending actual invoices from your software to our service, you use a separate Connection Key that is unique to each organization, to send your invoice data to our service. Sending invoices with the Connection Key to our service is initially in TEST mode (your invoices are sent to TEST environment of Tax Authority portals.). When you are ready to go-live, you switch your invoicing to the PROD environment and start sending invoices to the production environment of the tax authority portals.
You are testing only the integration between your software and our platorm. When this integration is confirmed, you job regarding the integration is mostly done.
After the integration, you are primarily in the TEST mode. In this TEST mode, you test the 5 possible distribution channels (tax authority portal, PEPPOL, intra-DDD Invoices platform delivery, other e-invoicing networks & e-mail) based on your requirements. Those invoices are send to the TEST environments of those channels. (For eMail, you test whichever mail you like). In the API response, you will get a proof feedback data that the invoices has been in the TEST environment.
Important: Our platform has established the connection with TEST environments of each of the distributions channels in covered countries. You do not have to deal with any of your own TEST environments.
After you select a business package & switch to PRODUCTION mode, your invoices will start going to the PRODUCTION environment of the distribution channels.
All data validation happens in the TEST mode, and is exactly the same as in PRODUCTION mode. The only thing that changes are the sending credentials, so that invoices are send to the PRODUCTION environment.
Because we accept simple .JSON object into our platform, you are responsible only for the data that you send to our platform. From that data we create compliant e-invoices or other invoice formats from it, we are always sure & responsible that generated invoices will be in correct format. All data validation required is done previously on our side, when covering the country.
All invoice calculations, rounding errors, delivery to tax authority etc. is tested by us.
You can add them manually or use a simple "Add customer" API. Each of your customers get's a specific connection key, so we know who is generating invoices.
The integration can be done with every software that can send an HTTP post/get request. If your software cannot do that, we will open a custom project for you and find additional possibilities.
You upload your and your customers certificates/API keys inside the administration module or via the API.
In the standard business packages, the requests are limited up:
- document (invoice, e-invoices) up to 1 per second / 1000 per hour - from one location
- fiscalization / dig. report up to 3 per second / 3000 per hour - from one location
If you have a use case to send all invoices in one request (e.g. Periodic mass billing) - you have to use a Mass. API for this purpose, available in the standard packages.
If you'd require higher frequency due to bursts of high volumes (e.g. events, holidays, etc.) that the ones above, please contact us to open the bandwidth.
We offer a manual invoice creation solution from our platform, if that would be required in the case of faster market launches, testing, temporary solutions etc.
For integrations, that would require a lot of effort on your side (complex changes in legacy softwares, internal organizational processes etc.) we offer a solution "Virtual Printer", that allows "printing" invoices into our platform from your software.
We monitor & maintain the tax authority requirements in-house, with people dedicated for that role. All changes in tax authority requirements are done by us, so your integration with our platform does not change. In the event of the breaking change, you would be notified at least one month in advance.
Yes, all the care for the constant provision of legal compliance is on our side.
Since we moved all the knowledge regarding technical e-invoicing schemas, legislation changes about e-invoicing rules and other government requirements inside of our platform, we handle vast majority of changes on our own.
In the event of breaking change for you (change of the specific key in the input .JSON, that would need to be sent to our platform) we notify you at least 1 month in advance, but those are extremely rare.
After you have integrated with our platform, most day-to-day changes on the backend side are invisible to you. In case of a breaking change (when you must change the object sent to us), you will be notified one month in advance.
Documents are signed with a digital certificate ensuring, that they are not modified after the creation. On demand, we can also ensure that document are equipped with EU-trust time-stamps.
You can acces status of invoices live at the "invoice-flow control module". You can also download all the data in the .xls and .csv.
When the tax authority is down, invoices can not access their portal.
We have two options to handle those cases, first one being to "repeat transactions". The second option is a "queing option", that if requested, have to be arranged during the integration phase. For this option, you'd have to prepare a push API end-point in your software.
This can be arranged based on your requirements. We can open an administration panel so that they can configure the required data & certificates for tax compliant invoicing and over-see their invoices.
We divide the issues into three categories and handle them under publicly published terms of operations (or custom-agreed SLA if required).
We provide you an invoice-flow control module, where the invoices with errors are separated from the successful transactions. The errors are served to you based on the specific codes, so you know exactly where and why did the error happened. The notifications about the errors, can be send to your software via the API so you/your clients are immediately notified about the error if it happens.
We have two options to handle those cases, first one being to "repeat transactions". The second option is a "queing option", that if requested, have to be arranged during the integration phase. For this option, you'd have to prepare a push API end-point in your software.
In that case the invoices are not even coming to our system. Your software should keep track of the invoices still issued, so when you are back online, can be re-issued to our platform with a special code (should be is implemented into the UI of your software) stating that invoice were reported to tax authority post-issuing due to internet issues (it's a known use case, and every tax authority have this code).
We are offering simple monthly/yearly subscription that grow with you requirements and is dependant on invoice quantity, number of legal entities using your software & functionalities. We are charging each country separately.
For individual companies and companies solving own invoicing we charge a set-up fee.
Please reach out to learn more.
For companies who requested a project based approach or enterprises, the price consist of the set-up fee, platform usage fees, potential project leading fee and potential custom work.
Please reach out to learn more.
Yes
We offer support in Slovenian, Serbian, Croatian and English.
The time-zone for support is CET.
Please look at our Support Level Agreement page: https:/
Yes, if requested. We ensure 99,5% uptime.
All received data is securely stored in a database that is not exposed to public internet. The database is backed up daily and backups are stored in encrypted form on two separate sites inside EU area. Document files are stored on a dedicated internal storage system, which is both compressed and encrypted and also has a separate redundant archive copy inside EU area. Both the data and encrypted documents are accessible to our servers that answer authenticated and authorized user requests over our API. Apart from this, your data and encrypted documents are only accessible to a limited number of internal administrative staff that can access them using a secure VPN, if needed, e.g. during an investigation of a potential problem.
The package that you choose determines if we store your data and documents either for an extended period or transiently. In the latter case, we ensure that your data and documents are deleted from all our systems inside 21-day period (but likely even sooner) after transmission via our platform. In the former case, we offer an arbitrarily long-term storage of your data and documents, as detailed in the packages.
We only store the data you send to our platform explicitly, and depending on your chosen package you can decide if we delete them or store them for later use of for compliant recall or tax audits, or that we store also the documents. We never store your plain-text passwords!
Yes, in all EU. Because some countries explicitly require storage of the data locally or in specially approved e-archives, we solve that by adhering to these requirements on the one-by-one basis.
Yes. There is no limit to the storage of your documents. You can decide if you'd also like to store the documents with us. See packages for more info.
When an organization stores documents with us, we keep them in two places:
Each document is stored with a unique ID and encrypted using AES encryption. We manage the encryption keys securely within our system. Both storage locations are backed up daily. If a document isn’t accessed for a while, it’s removed from primary storage but kept in the archive. If it’s accessed again, it’s restored to primary for faster future access.
Multi-Tenancy Options
Our system supports multiple tenants with flexible data isolation:
Our platform automatically routes requests based on the selected setup.
Our databases are in 2 locations, both in EU. Both locations are ISO 27001 or regional equivalent certified. Your data is also stored on a legal archive, with EU time-stamp & e-signature if requested.
All sensitive data especially is encrypted at rest using strong cryptographic standards. Our infrastructure is hosted in secure, ISO 27001- and ISO 9001-certified data centers located in the EU ensuring both physical and logical protection.
For data in transit, we exclusively use HTTPS with the latest TLS 1.2 and 1.3 protocols, ensuring all communication is encrypted with AES-256 or stronger. This guarantees that all data exchanged between our systems and external parties is protected at the highest level. Access to production systems is strictly limited, with no physical access granted to unauthorized employees.
