Custom VAT compliance software development
Appfront builds custom VAT compliance software: determining the correct rate and scheme per transaction, checking invoice requirements, compiling the VAT return and the ICP return, handling distance sales through the One Stop Shop, and preparing for mandatory e-invoicing under ViDA. For organisations whose VAT treatment does not fit a standard package.
What is VAT compliance software?
VAT compliance software answers three questions for each transaction: which rate applies, which scheme is relevant, and which details must appear on the invoice as a result. It then gathers those transactions into a VAT return, an ICP return and, where applicable, a report via the One Stop Shop. It is the layer between your sales system and your financial administration.
For a trading business with one rate and one country, that work is negligible. Once you supply customers in several EU countries, with a mix of goods and services, reverse charge, distance sales to consumers and intermediary trade, the number of decision rules grows faster than the standard fields in an accounting package can handle.
Custom software records your decision rules explicitly, applies them consistently to every transaction, and stores why each choice was made. That makes your filings reproducible and your records defensible during an audit. See also our broader approach to custom software development.
Decision rules, not assumptions
Rate, reverse charge and place of supply follow from an explicit rule model covering the nature of the supply, the status of the customer and the country. Every outcome can be traced back to the rule that determined it.
Returns from the source
The VAT return lines, the ICP return and the OSS report are built from the same transaction rules, so the reconciliation between turnover, general ledger and return does not have to be done by hand.
Ready for e-invoicing
Invoices are built according to the European standard EN 16931, so you can exchange them via Peppol and are prepared for the digital reporting obligation that applies under ViDA from 1 July 2030.
The invoice itself and the reporting per transaction form a separate track alongside the return chain. What changes under ViDA and why data quality needs to come first is covered on ViDA software.
How we build your VAT compliance software
We start with a sample of your own turnover: which transaction types actually occur, and how each is currently treated. Your tax adviser or accountant is involved from the first conversation, because the decision rules come from them, not from us.
We inventory your supply types, countries, customer categories and the schemes you apply. From a sample of actual invoices, we pick out the cases where the current treatment is doubtful or inconsistent.
We design the rule model for rate, reverse charge and place of supply, the transaction model that keeps the audit trail, and the integrations with your sales system, invoicing and general ledger. Your tax adviser reviews the rules before any code is written.
We build in short iterations and run each one against historical transactions, so differences between the old and new treatment become visible. We connect to your accounting system early on.
We go live with a period in which old and new run in parallel and the outcomes are compared. After that, ongoing management, monitoring and further development as rates, rules or European obligations change.
What VAT compliance software actually does
A wholesaler dealing in intra-Community supplies has different challenges from a software company selling digital services to consumers. These are the features we most often deliver.
Rate determination per transaction
Rules that determine the correct rate and classification based on type of supply, goods code, customer status and country, including exemptions and the zero rate. When a rate changes, the rule is updated with an effective date, not the code.
Reverse charge & place of supply
Support for the reverse charge mechanism in domestic and cross-border situations, and for the main place-of-supply rules for B2B and B2C services, with the basis for each invoice recorded.
Validating VAT numbers
Checking customers' VAT identification numbers via the European VIES system, recording the date of the check and the outcome. This is precisely the evidence you need if the zero rate is ever questioned.
Monitoring invoice requirements
Checking that every outgoing invoice contains the legally required details, including the statement that is mandatory for reverse charge or an exemption. See also our invoicing app.
Returns, ICP and OSS
Preparing the periodic VAT return, the EC Sales List and the reporting through the One Stop Shop for distance sales and digital services to consumers in other EU countries.
Purchase side & input VAT
Checking incoming invoices for VAT treatment and deductibility, and flagging discrepancies. Connects to invoice recognition and to your accounts payable process.
Who we build VAT compliance software for
VAT software becomes worthwhile once the number of exceptions outgrows what an accounting package can handle in its fields. These are the client types we most often build for.
Trade and wholesale
Businesses with intra-Community supplies, chain transactions and triangular trade, where the burden of proof for the zero rate is heavy. They mainly need watertight records per shipment and per customer.
Webshops and digital services
Sellers to consumers in several EU countries, who work with the distance selling threshold and the One Stop Shop. For them, rate determination per country and per product type is the most difficult part.
Accountancy and administration firms
Accountancy firms that file returns for many clients and apply different schemes per client. They often look for an environment that fits their own way of working; see also our accountant portal.
Organisations with mixed supplies
Healthcare institutions, education providers, cultural organisations and associations with both exempt and taxable turnover, where the pro-rata percentage for input VAT must be determined and justified every year.
Test your idea first: a working prototype in 1 day
With OneDayBuild, we turn your idea into something tangible in one day for €1,150, so you can see whether further development is worth the investment. Decide to go ahead with the full build? Then we credit the full cost.
Explore OneDayBuild →Technology and integrations
We build with a modern, maintainable web stack and connect to the systems that already record your sales and purchases, so no second set of books is created.
If your platform reports seller data to the Dutch tax authority, take a look at our DAC7 reporting integration.
Why choose Appfront for your VAT compliance software?
Appfront builds custom software and starts with your actual transactions. VAT software rarely fails on the arithmetic; it almost always fails on deciding which rule applies to which case. That is why we take the decision rules from your tax adviser or accountant and record them in a place where you can review them yourself.
We build the rule model with effective dates rather than hard-coding rates into the code. If a rate or threshold changes, that is a dated change in configuration, and earlier periods remain reproducible exactly as they were reported at the time.
Every outcome stays traceable. For each transaction line we keep which rule was applied, which data that rule used, and when it happened, with tamper-proof logging. In an audit, you can show not only the outcome but the route taken to reach it.
See also our broader services: custom software development and the e-Boekhouden integration. Questions about your situation? Get in touch.
- Decision rules from your tax adviser, explicitly documented
- Rates and thresholds as configuration with effective dates
- Justification stored per transaction line
- VIES validation with a record of when it was checked
- ICP return and One Stop Shop supported
- Invoices to EN 16931, ready for Peppol
- Prepared for digital reporting under ViDA
- Parallel trial period before going live
- Tamper-proof audit logging for inspection
- Ongoing maintenance when regulations change
Security and privacy in VAT compliance software
VAT software handles commercially sensitive data: revenue per customer, margins that can be inferred from prices, and, for small businesses, personal data. We apply data minimisation and set up authorisation based on role and need, so that not everyone with access to the return also sees the underlying customer revenue.
For the statutory tax retention obligation, we take a retention period of seven years for the administration and ten years for data on immovable property. Personal data that falls outside this is kept for a shorter period, in line with the GDPR.
Technically, we build to the OWASP security standards, with encryption in transit and at rest, role-based access and tamper-proof audit trails for calculations and corrections. More on our approach: information security policy and vulnerability disclosure policy.
- GDPR-compliant processing and data minimisation
- Tax retention periods kept separate from privacy periods
- Revenue per customer behind separate authorisation
- Tamper-proof logging of calculations and corrections
- Encryption in transit (TLS 1.2+) and at rest
- Role-based access and least privilege
- Reproducible return for each closed period
- Built to the OWASP standards
Frequently asked questions about VAT compliance software
Answers to the questions we are asked most often about custom software for VAT compliance.
VAT compliance software determines, for each transaction, the correct rate and scheme, monitors the statutory invoice requirements, and builds from that the periodic VAT return, the EC Sales List and, where applicable, the notification via the One Stop Shop. It sits between your sales system and your financial administration and keeps the justification for each line.
No. Your accounting package continues to keep the general ledger. Custom VAT software fills the layer in front of it: the decision rules that determine how a transaction is treated for tax purposes, and the justification for that. That layer is exactly where standard packages, which work with fields and free text, fall short when you need rules.
The One Stop Shop is the EU scheme that lets you declare and pay VAT on distance sales and digital services to private customers in other Member States through a single return in your own country, rather than registering separately in each country. It becomes relevant once your cross-border B2C turnover exceeds the European threshold.
ViDA stands for VAT in the Digital Age, the European package that modernises VAT rules. For cross-border B2B transactions, electronic invoicing in a structured format under the European standard EN 16931 becomes mandatory from 1 July 2030, with digital reporting to the tax authorities. We are already building towards that, so the transition does not mean a rebuild.
Yes. We validate VAT identification numbers through the European VIES system and record the time of the check and its outcome against the transaction. In practice, that record is the evidence you need when the zero rate on an intra-Community supply is challenged.
We record rates, thresholds and rules as configuration with an effective date, not as values hard-coded in the software. A change is then an administrative action with a date, and a closed period remains reproducible as it was reported at the time. That saves maintenance and keeps your history defensible.
Your tax adviser or accountant, not us. We build the model that records those rules explicitly and testably, run them against your historical transactions so that discrepancies become visible, and ensure every outcome remains traceable. Tax responsibility stays with you and your adviser.
We build custom solutions. The number of VAT exceptions varies greatly between organisations, and the question is never whether the software can calculate but whether it correctly recognises your specific cases. After an intake meeting, we agree together which transaction types matter most and in what order we develop them.
Ready to build your VAT compliance software?
Tell us which transaction types you handle and where VAT treatment is currently manual or open to debate. We are happy to think through the rule model, the connection to your accounts and preparation for e-invoicing with you. In a no-obligation first conversation, you'll get a clear picture of what is possible.