Custom municipal tax software development
Appfront builds custom software for the entire municipal tax process: tax assessment, WOZ valuation and decisions, objections and appeals, remission of taxes and debt collection. We integrate with base registers such as the BAG and the BRP, deliver WOZ values to the LV WOZ, and send the digital assessment to the Berichtenbox on MijnOverheid. Software that fits your by-laws and work processes, for municipalities, tax collaborations and water boards.
What is municipal tax software?
Municipal tax software supports the process of levying and collecting taxes: issuing assessments for property tax (OZB), waste charges, sewerage charges, dog tax and tourist tax, among others, the WOZ valuation and sending WOZ decisions, and handling objections, remission and debt collection. Several levies are often combined on a single assessment notice, with the WOZ value as the basis for property tax.
Custom software often fits this better than an off-the-shelf package: every municipality or tax collaboration has its own by-laws, rates, target groups and work processes, and works with a specific combination of source and back-office systems. Building the software to measure means it matches your by-laws, your assessment rules and your integrations, rather than forcing your process into the mould of a generic package.
Appfront builds this software around the integrations the tax process needs: property data from the BAG for the WOZ, subject data from the BRP, and digital delivery via the Berichtenbox on MijnOverheid. The application grows along with changing by-laws and stays reliable during the annual assessment run. This is part of our wider software for municipalities.
Levying and issuing assessments
Issuing assessments for property tax (OZB), waste and sewerage charges, dog tax and tourist tax, often combined on one assessment notice. Rates and levy rules follow your bylaws, with the WOZ value as the basis for property tax.
WOZ valuation and decision
Record and substantiate WOZ values, compile valuation reports and send assessment notices. Data is recorded in a verifiable way and delivered to the LV WOZ on time, in line with the Waarderingskamer's supervision under the Wet WOZ.
Objections, debt relief and collection
Handle objections within the statutory deadline, assess debt relief requests and monitor the collection process, including reminders and payment orders. The software keeps track of deadlines, case files and payment status for each taxpayer.
Our development process for tax software
We work to a method that removes uncertainty early and delivers a stable application. From an initial analysis of your by-laws, assessment rules and integrations, through to go-live and ongoing maintenance, every step is aimed at software your team can understand, check and trust, including during the assessment run.
We map out which levies you impose, which regulations and rates apply, which source registrations and back-office systems are involved, and how the objection, debt relief and collection processes work.
We design the data model around object and subject, the assessment and WOZ logic, and the integrations with the BAG, BRP, LV WOZ and the Berichtenbox, with a clear error handling and security strategy.
Implementation with automated tests, structured logging and monitoring. You see working versions along the way, so we can refine the assessment and objection processes together with your team.
Controlled go-live with data validation and a safety net, followed by ongoing management and further development, including processing new regulations and rates for each tax year.
What the software delivers in practice
Each application is tailored to your ordinances, levies and adjacent systems. Below are the features we most often deliver for municipalities, regional tax collaborations and water boards that want to support their tax, WOZ and collection processes.
Assessment issuing and tax roll
Compile assessments and include them in a tax roll, with several levies on a single notice. Rates and levy rules follow your regulations and are applied consistently, with the WOZ value as the basis for the property tax and verifiable calculations for each taxpayer.
WOZ administration and LV WOZ
Manage WOZ objects and values, compile valuation reports and supply and query values via the LV WOZ. Data is kept consistent with your own records, in line with the Waarderingskamer's independent supervision under the Wet WOZ.
Objection and appeal
Receive, register and link objections to the correct object and subject, with case management, re-valuation and drafting of the decision on the objection. The software monitors the statutory six-week deadline and keeps the status of each objection visible.
Debt relief and collection
Assess debt relief requests, where possible through automated checks, and monitor the collection process with reminders, payment orders and related costs. Deadlines, payment arrangements and documents are tracked for each taxpayer.
Digital assessment in the Berichtenbox
Deliver the assessment and WOZ notice digitally to the MijnOverheid Berichtenbox, provided the person concerned has opted in. Residents log in with DigiD to view their assessment and valuation report, with paper post as a fallback where necessary.
Integrations with source registers
Object data from the BAG and subject data from the BRP flow reliably into the tax process, with data exchange between government bodies via Digikoppeling where needed. Data remains traceable, so that assessments and WOZ values are always based on the correct object and subject data.
Which organisations use this
The tax process differs from organisation to organisation, but a number of variants come up often. For each of these, the software can be tailored, with attention to the specific ordinances, integrations and target groups of the government organisation in question.
Municipalities
Municipalities that levy and collect their own taxes: property tax (OZB), waste and sewerage charges, dog tax and tourist tax, with WOZ valuations and decisions. The software aligns with your own ordinances and connects to a municipal website for viewing and payment.
Tax collaborations
Regional tax collaborations that levy and collect for multiple municipalities and sometimes a water board. A single application can account for several participating organisations, each with their own ordinances, rates and house style, so a collaboration can serve different clients at the same time.
Water boards
Water boards that impose water board taxes, such as the watersysteemheffing (water system levy) and the zuiveringsheffing (treatment levy). The levy, assessment and collection process closely resembles that of municipalities and can be supported in the same custom software. See also custom software for water boards.
Inspection and objections by residents
Residents and businesses who want to view their assessment and WOZ value, review the valuation report, make a payment or lodge an objection. This is available via the Berichtenbox and through a citizen portal where residents manage their tax matters themselves using DigiD.
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 use
We build on a modern, maintainable web stack and set up the software so that your own team or a future supplier can manage and further develop it. For the tax process, the integrations with source registers and national facilities are at the heart of the solution. We connect to the BAG for object data, the BRP for subject data, the MijnOverheid Berichtenbox for the digital assessment and Digikoppeling for data exchange between government bodies, including towards the LV WOZ.
On the side of the landlord, who maintains the register and files returns per municipality, there is our app for the nightly register and tourist tax.
Why choose Appfront for your tax software?
Appfront builds custom software for organisations in the Netherlands, with an understanding of the government domain and the integrations that come with it. We always start with a thorough analysis of your ordinances, processes and existing systems: software must not only work technically, but also add practical value to the way you work.
On every project we write clear documentation and ensure that your own team, or a future supplier, can understand and manage the software. No black box, but transparent code and clear agreements on monitoring, alerting and maintenance. This way, you avoid dependence on a single supplier.
You work with a dedicated point of contact who understands both the technical and functional sides of the tax process. This keeps communication lines short, prevents misunderstandings and speeds up decisions when choices need to be made during development.
See also our broader services around software for municipalities, housing association software and AI for municipalities and government.
- Custom development around your regulations, rates and assessment rules
- Integrations with the BAG, BRP, LV WOZ and the MijnOverheid Berichtenbox
- Secure by default — GDPR, BIO, role-based access and audit logging
- Clear documentation and transparent code, without supplier lock-in
- A dedicated point of contact who understands the tax process
- Ongoing maintenance and further development per tax year
Security and privacy in tax software
Tax software always processes personal data and financial information about residents and businesses. Appfront builds in line with the Baseline Informatiebeveiliging Overheid (BIO), with data minimisation as the starting point: we only process the data needed for the assessment, the WOZ valuation and collection. Access is role-based and follows the least-privilege principle.
We document the data flows and integrations so your processing register is complete and you can demonstrate compliance with the GDPR. Actions in the system are logged, so tax assessments, WOZ decisions and recovery steps remain traceable. Where residents use the software directly, for example through a citizen portal, we take account of digital accessibility requirements (WCAG 2.1 AA / DigiToegankelijk).
Discuss your situation with us without obligation via our contact page — we are happy to think along with you about the security and set-up of your tax process.
- GDPR-compliant data processing and data minimisation
- Built to the Baseline Informatiebeveiliging Overheid (BIO)
- Encryption in transit (TLS 1.2+) and at rest
- Role-based access and least-privilege principles
- Audit logging with traceable actions
- Monitoring and alerting for anomalies
- Digital accessibility (WCAG 2.1 AA) for residents
- Documentation for your record of processing activities
Frequently asked questions about municipal tax software
Answers to the questions we are asked most often about custom software for municipal taxes.
Custom software for municipal taxes supports the full process of levying and collecting taxes: issuing assessments for property tax (OZB), waste charges, sewerage charges, dog tax and tourist tax, among others, WOZ valuation and sending WOZ decisions, and handling objections, remission of tax and recovery. The software is built to order around your actual processes and by-laws, and integrates with source registers such as the BAG and the BRP and with national facilities such as the LV WOZ and the MijnOverheid Message Box.
WOZ valuation and municipal tax assessment are directly linked: the WOZ value forms the basis for the OZB and other charges. Custom software supports recording and substantiating WOZ values, compiling valuation reports and sending WOZ decisions, often combined on a single tax notice. The Valuation Chamber (Waarderingskamer) independently supervises the implementation of the Wet WOZ; software helps you record data consistently and verifiably and deliver it to the LV WOZ on time.
A resident or business can lodge an objection against the assessment or the WOZ value within six weeks of the date of the assessment. Custom software supports the entire objection process: receiving and registering objections, linking them to the relevant property and taxpayer, building the case file, revaluation, and drafting a decision on the objection within the statutory deadline. Lodging an objection does not automatically suspend payment, so the software tracks payment and objection status separately.
Remission of tax is intended for residents who have too little income or assets to pay municipal taxes. The software supports the application, automatic checks where possible, and manual assessment of remission requests. If an assessment is not paid on time, the recovery process begins: a reminder, a payment order (dwangbevel) and further steps with the associated costs. The application monitors deadlines, generates the correct documents and keeps the file for each taxpayer complete.
For the tax process, integrations with source registers are crucial. Property data for the WOZ comes from the BAG, taxpayer data from the BRP, and WOZ values are supplied to and queried from the LV WOZ. The digital assessment and WOZ decision can be delivered via the MijnOverheid Message Box, and exchange between government bodies runs via Digikoppeling where needed. Appfront builds these integrations to order, so data flows reliably and traceably between systems.
The assessment and WOZ decision can be delivered digitally to the MijnOverheid Message Box, provided the person concerned has indicated that they wish to receive post from the municipality or tax partnership digitally. Residents log in with DigiD to MijnOverheid or their municipality's portal to view the assessment and valuation report. The software can combine this digital delivery with a citizen portal for viewing, payment and lodging objections.
Custom software always contains personal and financial data and falls under the GDPR and the Baseline Informatiebeveiliging Overheid (BIO). Appfront builds with data minimisation, role-based access, encryption in transit and at rest, and comprehensive logging, so that actions remain traceable. Where residents use the software themselves, for example via a citizen portal, we take the digital accessibility requirements (WCAG 2.1 AA / DigiToegankelijk) into account. Data flows are documented for your record of processing activities.
Alongside individual municipalities, many regional tax partnerships operate, such as collaborations that levy and collect taxes for several municipalities and sometimes a water board. Water boards themselves also impose taxes, such as the water system levy and the wastewater treatment levy. Custom software can handle multiple participating organisations, their own bylaws, rates and house styles within a single application, so a partnership can serve different clients at the same time.
Ready to have your tax software built?
Tell us which levies you impose, what your WOZ, objection and collection processes look like, and which base registrations the software needs to integrate with. We're happy to help you think it through, covering assessments, WOZ property valuations, objections, hardship remission and digital assessments via the Berichtenbox. A no-obligation first conversation will quickly give you a clear picture of what's possible.