Industry · Accountancy

AI for accounting firms. Custom-built, tested in practice.

We build AI applications that fit how an accountancy firm actually works: invoice processing, audit assistance, client communication and compliance. Not a standalone AI package bolted on top, but an integrated workflow in which Twinfield, Exact, AFAS or CaseWare keep doing what they do well, while AI speeds up the work around them. With audit trail, AI Act governance and data sovereignty built in from the design stage.

SegmentMid-market
SegmentTax advisory
SegmentAudit & assurance
SegmentTrust & notarial

Dutch accountancy in figures.

~700
Accountancy organisations holding an AFM licence
~22.000
RA and AA registered with the NBA
~14M
Incoming invoices per year across SME accounting packages
71%
Expect concrete AI deployment within three years

Source: AFM register, NBA annual report 2024, accountancy sector survey 2025.

Off-the-shelf AI tools cover roughly half.

The major vendors — Wolters Kluwer CCH iFirm, Visma, Exact, AFAS, CaseWare — have built AI modules into their products. For standard invoice processing, bank transaction categorisation and basic OCR, these work satisfactorily. Until a firm has its first non-standard requirement. A proprietary risk framework for the audit, a sector-specific check for a healthcare or housing association client, an onboarding flow that must cover Wwft, UBO and sanctions list screening in one step — that is where the standard package stops.

Mid-market accountancy firms often struggle with the combination of five or more systems: the accounting package, CRM, document management system, e-invoicing platform and AML tool must work together as one coherent flow. Big Four spin-offs and challengers want their own LLM workflow in which client data is guaranteed not to leak to OpenAI or Anthropic, and they often build their market position on that data sovereignty. Tax advisory firms have their own clause libraries and advice templates that no generic AI can handle. Bookkeeping cooperatives want a white-label tool that all affiliated members can use, without the cooperative having to set up its own IT team. Trust firms with an accountancy arm face AML and sanctions list screening that differs by jurisdiction, and UBO structures more complex than any standard onboarding can handle. Civil-law notaries with financial and governance advisory work face the same compliance requirements and can often reuse the same flows.

That is where we build the custom layer. Not a replacement for Twinfield or CaseWare, but an AI layer on top that supports precisely the flow that sets your firm apart. With the right governance, a watertight audit trail and compliance from the first sprint. Our starting point is always: what do you do better than other firms, and how can AI make that distinctive expertise more scalable without compromising the quality of judgement?

For which firms do we build?

Mid-market accountancy firms

Ten to a hundred staff, a distinct identity and specialisation, often with clients in one or two sectors for which the standard packages do not quite fit. This is where most demand for integrated AI flows across five or more systems sits.

Big Four spin-offs and challengers

Firms founded by former partners of the Big Four that differentiate themselves with a specific audit approach, a proprietary risk framework or deeper sector expertise. They often build their market position on data sovereignty — a proprietary AI layer fits that perfectly.

Tax advisory firms

Their own clause library, their own advice templates, their own lines of interpretation. Generic AI offers little there; a private LLM flow trained on the firm's own knowledge base does.

Bookkeeping cooperatives

Dozens or hundreds of self-employed bookkeepers who collectively want an AI platform, presented white-label from the cooperative. Build once, roll out many times, with central governance and local autonomy.

Trust firms with an accountancy arm

Complex UBO structures, AML screenings per jurisdiction, sanctions list checks that shift every quarter. Off-the-shelf packages are rarely sufficient here; for this type of firm, custom AI is more the rule than the exception.

Notaries with financial and governance advisory

Notaries who, alongside deed execution, also provide governance advice and tax planning face much the same compliance and AI requirements. The workflows we build for accountancy firms lend themselves well to reuse here.

AI applications we typically build.

Four areas where we develop custom AI for accountancy firms in practice. For each area: the flow, the integrations and the governance required.

Invoice and bookkeeping automation

OCR is no longer a differentiator; the value lies in classification. An LLM that learns, for each client, which cost centre belongs to which supplier, which VAT rate fits which type of expense, and which document category the firm uses. The accountant only sees the exceptions, not the standard rules.

We build that flow on a custom LLM layer, connected to Twinfield, Exact, AFAS or another accounting package. This includes receipt extraction via a mobile app, batch categorisation of bank transactions, and anomaly detection in annual accounts across years and against sector benchmarks.

  • Intelligent invoice classificationOCR plus LLM classification of document category, VAT rate and cost centre, learning per client.
  • Receipts app for clientsMobile extraction with automatic linking to cost centre and project.
  • Bulk bank transaction categorisationLLM batches with per-client training data, with no data leakage to public models.
  • Annual accounts anomaly detectionVariances between financial years, sector benchmarks and industry-specific outliers flagged automatically.

Three other areas where AI makes the difference.

Audit assistance. On assurance engagements, the work is shifting steadily from execution to judgement. An LLM that scans the ledger for red flags for the auditor, audit sampling that combines statistical sample selection with risk-based scoring, and anomaly detection across financial years and sector benchmarks: this is where we see most implementations. MindBridge AI Auditor is often the commercial starting point; we come into the picture when a firm wants its own risk framework that does not fit a standard package. Think of healthcare accountancy, where DBC checks and NHC classifications need to be automated, or housing association audits, where the DAEB and non-DAEB split must be verified separately. The audit team retains ultimate responsibility; the AI does the groundwork and flags where human judgement is essential.

Client communication. A mid-sized firm sends thousands of emails a week: questions about VAT returns, annual accounts components, payroll details, tax changes. A large share of these are repetitive. A well-built client communication assistant reads incoming mail, recognises the intent, and drafts a reply referencing that client's relevant files. The accountant or tax adviser reviews and amends; substantive responsibility remains entirely human. For mid-market clients we often build a CFO-as-a-service layer on top: an automatically generated monthly report commentary to which the firm adds its own perspective and advice before it goes to the client. It scales advisory work to many more clients without losing the feeling of personal contact.

Document classification and DAS. Incoming post, whether physical or digital, now needs to be routed automatically: a UBO notification, a Wwft document, a VAT correction, a revised annual account. A classification model layered over scanning software can do this with considerable accuracy. On top of that we build Document Automation Solutions: standard reports, audit statements and advisory templates that produce a first draft from client data, after which the accountant completes and signs the document. It saves most time in the assistant role, where capacity is currently scarcest. For VAT return and payroll checks we build similar flows, in which the LLM cross-references collective labour agreement (CAO) application, holiday entitlements and shift allowances against the client's input, and refers outliers to a payroll administrator.

Compliance from the very first sprint.

AI in an accountancy firm touches more regulation than almost any other sector. From the design stage we work within the frameworks of the Wta, NV COS, AFM supervision, GDPR, the AI Act, the Wwft and the forthcoming CSRD obligations.

Wta & NV COS

Professional rules for accountants

The Dutch Act on the Supervision of Accountancy Organisations (Wta) and the Dutch professional standards (NV COS) set requirements for independence, professional competence and file documentation. Our AI flows respect that separation: the AI supports, the RA or AA remains ultimately responsible and visibly performs the final step.

AFM supervision

Auditable AI decisions

The AFM increasingly scrutinises AI use at licence holders. We build an audit log for every AI decision: which model, which prompt, which input, which output, and which human review step. An AFM supervisor can reconstruct every decision.

GDPR Art. 35

DPIA and client data privacy

Bookkeeping inherently contains personal data and special category data of clients' clients. We deliver a DPIA covering data flows, retention and data subject rights. For LLM flows, depending on the firm, we choose on-premise models, EU-hosted inference or a private endpoint with no data retention.

AI Act Art. 4

AI literacy in the firm

Mandatory since February 2025: every employee working with AI systems must demonstrably be AI-literate. Delivery includes a training package and documentation. Where relevant, we link to our AI literacy training.

Wwft

AML and client due diligence

The Wwft requires a risk-based approach to client onboarding. Our flows automate UBO checks, sanctions list screening and PEP checks, with human assessment for every enhanced-risk flag. We explicitly build in sector differences across trust, accountancy and legal services.

CSRD

Sustainability reporting

The Corporate Sustainability Reporting Directive is reaching accountants through the assurance role. AI helps with data aggregation from client systems, scope 1/2/3 classification and consistency checks across years. We build this as a standalone module that connects to the existing audit flow.

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Seamlessly connected to the accountancy ecosystem.

We don't replace your accounting package or audit tool. We integrate with it, add AI where it adds value, and let Twinfield, CaseWare or AFAS keep doing what they have done well for years.

Twinfield
Visma bookkeeping package
Exact Online
Mid-market bookkeeping
AFAS
ERP & payroll
CaseWare
Audit software
CCH iFirm
Wolters Kluwer suite
Klippa
Document & receipt OCR
Basecone
Invoice scanning and recognition
KvK + UBO
Trade Register API

Custom development where off-the-shelf offerings end.

For commodity flows we almost always recommend the standard offering. A Klippa or Basecone for pure receipt scanning is faster and cheaper than anything we could build, and we say so. We only come into the picture when more than three systems need to work together, or when the AI layer requires its own risk framework or sector-specific flow that the standard packages do not cover.

Think of healthcare accountancy with automatic DBC checks, housing association audits with a DAEB/non-DAEB split, or a cooperative of independent bookkeepers that wants a shared white-label AI tool. For these kinds of challenges we build the custom solution and integrate it tightly with your existing stack, often drawing on our experience with custom LLM integrations and custom accountancy software.

The architecture always follows the same pattern. We place a thin abstraction layer between the AI model and the accounting package, so that either the model or the underlying stack can be swapped out without rewriting the business logic. Prompts and model choices are version-controlled, tested against representative client data, and automatically evaluated for accuracy before a new version reaches production. That is deliberate: the LLM landscape changes every few months, and a firm running GPT-4 today should be able to move to Claude 5 or an open-source alternative next year without fuss, if that suits better on price, speed or compliance.

From first exploration to ongoing management.

An AI project for an accountancy firm has its own rhythm, quite different from a standard software implementation. Five phases that are identical for every firm.

01 · Audit

Workflow mapping

A day in the office with a partner, controller and paralegal. Goal: which workflows genuinely cost time, where the AI potential lies, and where it does not.

02 · Design

AI scope and risk classification

For each use case we determine the AI Act risk class, the level of governance and the data flow. Result: a design that an AFM supervisor can follow.

03 · Build

Fortnightly sprints

Each sprint delivers one working AI workflow. Accountants test along the way. We work with both public and private LLM endpoints, depending on data sensitivity.

04 · Rollout

Phased go-live

First one team or client group, then the next. Each rollout includes training, documentation and the mandatory AI literacy module for users.

05 · Maintenance

Ongoing

We handle model monitoring, drift detection and regulatory changes under a maintenance subscription. First-line response within the same working day.

How the sector sees AI.

NBA Vision 2025

"AI is shifting the accountancy profession from executing to exercising judgement. Firms investing now in their own AI workflows are building a distinctive position with clients in the mid-market segment."

Accountant Adviseur, March 2025

"Custom AI is on the rise at firms that don't fit the standard packages. Sector-specific audit flows and combined Wwft screening are the two most requested applications."

AFM publication on AI in the financial sector

"The AFM expects licence holders' AI decisions to be verifiable, traceable and ultimately human-accountable. An audit trail and governance documentation are therefore not optional but the starting point."

Answers for the firm just starting with AI.

The questions we hear most often from directors, controllers and IT managers in accountancy.

What does AI actually do in an accountancy firm?
In practice we see four main applications: invoice processing and bookkeeping automation (OCR plus LLM classification), audit assistance (anomaly detection and sampling), client communication (generated reply drafts that the accountant verifies) and compliance (Wwft screening, UBO checks, AML). In addition, AI is increasingly used for CSRD reporting and in a CFO-as-a-service role for mid-market clients, for example automatically generated commentary on monthly reports.
Does AI replace the accountant?
No, and that is not what the regulations allow either. Under the NV COS and the Wta, a RA or AA remains ultimately responsible for the judgement. What AI does is make the executional, repetitive tasks faster. The accountant does more assessment and advice, and less data entry. For mid-market clients this often means more room for the strategic conversation.
Which AI tools already work well in accountancy?
For commodity flows, the off-the-shelf packages are usually the right choice: Klippa and Basecone for invoice OCR, Twinfield and Exact for accounting AI, MindBridge AI Auditor for audit-specific analysis, CaseWare for audit working papers. We actively recommend them when they fit. We only come into the picture when the flow requires deep integration between five or more systems, a custom risk framework, or sector-specific logic that no package offers, such as healthcare accountancy with DBC checks.
Privacy: does client data leak to OpenAI or Anthropic?
That depends on how it is built. In our standard design, client data never goes to the public APIs of OpenAI or Anthropic. We work with EU-hosted private endpoints (Azure OpenAI under a no-data-retention contract, Anthropic via a private endpoint, or on-premise models such as Llama and Mistral for the most sensitive flows). For every implementation, we document explicitly which data is processed where, in a data-flow document that forms part of the DPIA.
How do we combine GDPR, the Wwft and the AI Act at the same time?
By treating them as one coherent framework rather than three separate compliance requirements. GDPR governs data flows and retention periods, the Wwft determines which checks are needed during client onboarding, and the AI Act determines the risk classification and governance requirements. For every implementation, we deliver a single integrated document that covers all three frameworks, with explicit choices per flow. For the organisation-wide approach, we often refer on to enterprise AI implementation.
What determines the cost of an AI project for an accountancy firm?
Three factors: the number of systems we integrate with (one accounting package is different from five systems combined), the governance level that fits the AI Act risk class (high-risk requires considerably more documentation and testing), and how much of a dedicated LLM layer the firm wants (a private endpoint or on-premise model costs more than a public API with a DPA). We work with a fixed sprint budget and, after the design phase, give a concrete price for the full build.
How does implementation work in practice?
We start with a workflow audit: a day at the office with a partner, a controller and a paralegal. We then design the AI scope and risk classification. We build in two-weekly sprints with direct testing by accountants, and the first working flow is usually in place after a few sprints. Rollout is phased by team or client group, with training and the mandatory AI literacy module. After that we move to ongoing management, with model monitoring and maintenance as the legislation changes.
Do you also work with smaller firms, or only mid-market?
Custom AI is rarely the right choice for a firm with fewer than about ten employees. Twinfield, Exact or a Klippa subscription usually provide enough AI functionality for the price. We mainly get involved with firms of ten to a hundred employees, Big 4 spin-offs, bookkeeper cooperatives that want a shared white-label tool, and trust offices with an accountancy arm where regulatory complexity outgrows the standard package. A good AI strategy often starts with a broader conversation about AI strategy.

Ready to make AI concrete in your accountancy firm?

A half-hour introductory conversation with a partner and a controller or IT lead. We listen, ask questions and give an initial direction: which AI use cases will deliver the most value for you, and where you are better off keeping the standard package. No obligation, no sales pitch.

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