Service · App development

Custom expense claims app development for your organisation.

An expense claims app that works the way your people work: photograph receipts on the go, log mileage automatically, record hours against projects, and then export cleanly to your accounting or payroll software. Built around your workflow, not the other way round.

OCR receipt scanningMileageTimesheetsApproval workflowAccounting integration

Why a custom expense claims app?

Off-the-shelf expense software is designed for the average organisation, and you notice it straight away when your claims process works slightly differently. Different cost centres, more complex approval chains, a mileage allowance that isn't in the standard package, or healthcare claims that need to go to several insurers: that's where you hit the limits of the package. Workarounds in Excel, exports that have to be edited by hand, receipts circulating by email are all symptoms of software that wasn't built for your process.

We build expenses apps for organisations that take their processes seriously. With direct integration into your accounts or payroll system, a mobile interface your field staff, consultants or care workers actually use, and an approval flow that suits how your managers and finance team work. We have been building business mobile apps since 2015, and the pattern repeats itself: once the expenses app matches how employees really work, the number of incorrect claims falls and processing times drop sharply.

An expense claims app touches many parts of your organisation: HR for user management, finance for approval rules and general ledger mapping, IT for security and device management, and ultimately every employee who incurs costs. We involve these stakeholder groups in the first sprints, because an app that keeps finance happy but annoys field staff won't be used, and you'll still be left with an expensive Excel process running in the background.

For digital expense processing and custom digital expense software, the more specific you can make your requirements, the sharper the solution will be. A good expense claims tool adapts to your way of working, not the other way round, and that is exactly where off-the-shelf platforms fall short.

Three types of expense claims app.

Which format suits your organisation depends on the type of claims, the number of users and the integrations with your existing systems. In the first conversation we advise which direction makes sense.

Compact project · fixed sprint budget

Expenses and receipts app

A mobile app where employees photograph receipts. OCR automatically picks up the amount, VAT and supplier, and the claim passes through a short approval flow into your accounting. Suited to business travel, lunches, office purchases, allowances and small purchases made by staff. The finance team only checks the exceptions; the rest is processed automatically.

OCR receipt scanningPhoto uploadManager approvalAccounting export
Mid-sized project · fixed sprint budget

Hours and mileage expense claims

For consultants, lawyers, project teams and field staff who charge expenses to a client or project. Log hours against project and activity, mileage via route tracking or manually, and integration with your time recording or project administration. Export to invoicing or payroll, with automatic calculation of travel allowances and commuting adjustments under your own policies.

Time recordingRoute trackingProject integrationPayroll export
Larger project · fixed sprint budget

Sector-specific expense platform

For care providers claiming from health insurers, municipalities handling Wmo claims, or insurers processing damage claims. Custom validation against product codes, compliance checks, an audit trail and bulk processing to external parties. Includes integrations with sector-specific exchange standards and reports your controllers and accountants can use straight away.

Reporting per transaction leaves too much to gather at month-end. We build the capture of purchase receipts at the point of purchase in the ViDA app.

Product code validationCompliance checksAudit trailBulk export

What you get at the end.

A production-ready expense platform, plus everything needed to run it in-house. We deliver custom software that you own outright, with no annual SaaS fee you can never escape.

  • Mobile app for iOS and AndroidNative or cross-platform (React Native or Flutter), depending on your requirements. With offline mode, so a field worker without coverage can still submit claims.
  • Web portal for finance and managementProcess approvals, bulk-export claims, run reports and manage users. The same data, a different interface.
  • Accounting and payroll integrationsDirect integrations with Exact Online, AFAS, Twinfield, Yuki or another system. Not just export, but also synchronisation of cost centres, projects and general ledger accounts.
  • Full source code and documentationYou own the codebase, deployment instructions and architecture overview. No agency-level vendor lock-in.
  • Training for finance and IT teamsHow to manage approval rules, how to add new categories, and how to use the audit log during an accountant's review.
  • Maintenance contract (optional)Monitoring, updates for new iOS and Android versions, security patches and ongoing development. Fixed monthly fee, with clear response times by service level.

When an expense app makes sense.

Four patterns in which we guide clients. If one of them sounds familiar, we would be happy to discuss your specific situation.

Field staff

Staff on the move

Engineers, sales representatives, consultants or care workers who are on location all day. An expense app on the phone saves you from spreadsheets every evening and from lost receipts. Snap a photo of the receipt at the petrol station, and it's done.

Approval workflow

Manager approval required

Your finance department cannot, and should not, check everything itself. An approval flow in which the direct line manager signs off first reduces errors and speeds up processing. Includes value thresholds and escalations.

Volumes

Hundreds of claims per month

At some point, handling expenses manually in Excel or with a PDF form becomes unsustainable. With hundreds of claims a month, automated processing quickly pays back the investment, in time saved and fewer errors.

Compliance

VAT and audit trail

To reclaim VAT, the receipt must be traceable and retained. For healthcare or government claims, more extensive logging is required on top of that. An in-house platform keeps this structurally in order.

How an expense app project runs.

1

Introduction

A conversation to understand which type of expense flow the app needs, which systems sit behind it (accounting, payroll, ERP), and which compliance requirements apply to your sector.

2

Planning & user research

A workshop with your finance and IT team, plus interviews with the end users: the staff who will be submitting expenses on their phones. At the end, you receive a concrete scope, a timeline and the first screen flow.

3

Building in sprints

A working build every two weeks: first the receipt flow, then mileage and hours, then the approval and export flows. You and a few key users test along the way. A first tier is usable in a limited pilot within a few sprints.

4

Pilot & rollout

We start with a small group, often a single department or region. We fix bugs, fine-tune the approval rules, and then roll out in stages across the whole organisation, including training and short video tutorials for end users.

5

Maintenance & further development

iOS and Android release new versions every year, accounting integrations change their APIs, and users keep asking for new features. Ongoing maintenance keeps the platform up to date and reliable.

Not yet sure about a large project?

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 →

The organisations we build for.

The shape of an expenses app varies considerably by sector. What recurs in every variant: mobile input on the go, smart validation, and a clean integration with the system where the claim ultimately lands.

SMEs with field staff

Engineers and sales representatives

Service organisations, technical wholesalers, installation companies and facilities providers. Employees cover mileage on the road, buy materials for a job, and pay for meals while out. The expense app replaces paper forms and loose photos sent via WhatsApp.

Advisory firms and law practices

Timesheet and expense claims per client file

Consultants, lawyers, accountants and interim managers record hours against clients and projects. Travel costs, mileage and any out-of-pocket expenses to be recharged come on top. We link that data to your time recording and invoicing so that recharging happens in a single export.

Healthcare providers

Claims to health insurers

Mental health institutions, physiotherapy practices, home care and community nursing submit claims to various health insurers using product codes, indications and outcome measurements. We build flows that comply with the applicable standards and catch incorrect claims at the source.

Municipalities & insurers

Social support and damage claims

For municipalities, Wmo claims with the associated messages; for insurers, damage claim apps for policyholders and intermediaries. Bulk processing, validation against policy or decision data, and an audit trail that supports every check.

Tools and integrations we use.

We work with the mainstream stack for business mobile apps and integrate with the systems your finance and HR teams already use. No exotic dependencies, no vendor lock-in.

  • Mobile: React Native or FlutterOne codebase for iOS and Android, with native modules where needed (camera, location, offline storage). We also run fully native iOS and Android projects when the business case calls for it.
  • OCR engines: Google Vision and AzureFor receipt recognition we combine cloud OCR with our own post-processor that handles Dutch VAT rates, suppliers and date formats particularly well.
  • Accounting: Exact, AFAS, Twinfield, YukiFor the Dutch market these are the most requested integrations. We work through official APIs and ensure robust sync of cost centres, projects, general ledger accounts and VAT codes.
  • HR & payroll: Nmbrs, Loket, VismaFor mileage allowances, travel costs and home-working allowances, expense claims often run through the payroll cycle. We integrate with the well-known payroll packages so the adjustment rolls through every month.
  • SSO: Microsoft Entra, Google Workspace, OktaNo separate passwords for your employees. We connect to your existing identity provider, with conditional access and device policies wherever your IT team requires them.
  • CRM and ERP for rechargingWhere costs need to be recharged to a client or project, we integrate with your CRM (such as HubSpot) or ERP. The same data, one source of truth.
  • Hosting: AWS, Azure or Google CloudEU regions for data residency, encryption at rest and in transit, automatic backups and monitoring. Or within your own cloud tenant, if compliance requires it.

Frequently asked questions.

What clients want to know before we start on an expense claims platform.

Can the app integrate with our accounting or payroll software?
Almost always. For the Dutch market we regularly work with Exact Online, AFAS, Twinfield, Yuki and Unit4. Sometimes via official APIs, sometimes via an intermediate step with CSV export. We map in advance which fields need to flow between your accounts and the app — cost centres, general ledger accounts, projects, VAT codes — and make sure the app matches them. See also our smart API integrations for what is possible.
How reliable is OCR for scanning receipts?
On modern mobile cameras, OCR is very strong for legible receipts — the amount, date, VAT rate and supplier are usually recognised correctly. For smudged or crumpled receipts, it falls back to manual correction by the user. We always build in an edit step before the claim is submitted, and the original photo is kept for checking by finance or the accountant.
What about VAT reclaim and tax compliance?
The Dutch Tax Authority (Belastingdienst) sets requirements for expense administration: keeping photos of receipts, a clearly identifiable VAT amount, and a demonstrable link to the general ledger. We build this in as standard: original receipts are stored encrypted, an audit trail logs every change, and the export to your accounting system includes all the fields your accountant needs. For business mileage and home-working allowances, we follow the tax rules in force at the time of delivery.
Does the app also work offline, for example for field staff?
Yes. For field staff and engineers, offline mode is essential — coverage on site is often poor. We build local storage so that photographing a receipt, logging mileage or creating a time entry always works. As soon as the device is back online, everything syncs automatically with the server. See also our field service app page for the broader context.
Does this comply with GDPR, and how do you handle sensitive receipts?
Receipts and mileage records contain personal data and location data, so GDPR is the guiding framework. We carry out a DPIA for every project, use encryption in transit and at rest, enable an audit log by default, and put clear data processing agreements in place. Care-sector claims additionally fall under NEN 7510 where applicable. We host data in the Netherlands or the EU, according to your preference.
What determines the cost of a custom expense claims app?
Three factors: the number of expense types (receipts only versus receipts + hours + mileage + care claims), the complexity of the approval workflows and cost centre structure, and the number of integrations with external systems. In the introductory meeting we give you an honest indication based on your specific situation. This is always custom software that you own, not a per-user subscription.
Do you also build for care, Wmo or insurance claims?
Yes. For healthcare providers, we build claim flows to health insurers with the correct product codes and validations. For municipalities, Wmo claims with the associated message exchange. For insurers, claims apps for customers or intermediaries. The underlying principles are always the same, mobile-first UX, smart validation and integration with your core systems, but the domain logic varies considerably by sector.
Can we start small and expand later?
We often recommend this. Start with one expense type, for example only out-of-pocket costs, for one department. Once that is running, we add mileage, hours or a new organisational unit. The architecture is designed for this: new modules, new approval rules and additional integrations (for example an ERP integration or CRM integration) arrive in later sprints without touching the existing flow.

Talk to us about your expense claims app.

A free, no-obligation half-hour introductory call. We listen to your expense claims process, ask questions about your systems and offer direction you can use straight away, even if we ultimately don't work together.

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