Service · App development

Build a booking site app that fits your flow.

A custom booking and reservation app for hospitality, fitness, hairdressers, healthcare, restaurants, meeting venues, car rental, sports trainers, coworking spaces or escape rooms. Real-time availability, payments via Mollie or Stripe with iDEAL, waitlists, automatic no-show fees, loyalty and multi-resource scheduling, integrated with your till, calendar and marketing stack. For organisations that have outgrown Mews, Booking.com or Resengo because those platforms no longer support how they work.

Real-time availabilityMollie & StripeWaitlistMulti-resourceLoyalty & referrals

Arrange an introductory call See a booking case study

A booking app is more than a calendar with a payment button.

Most organisations in the Netherlands that take bookings, such as a hotel chain, a fitness brand, a hairdressing chain, a healthcare practice, a restaurant group or a coworking operator, began with a SaaS booking tool like Mews, Booking.com, Resengo, Salonized, Treatwell, Eversports or a similar platform. That's deliberate: such a tool is quick to go live and covers around 80% of what you'd expect as standard. The problem arises when the organisation grows, the offering becomes more complex, or the business model comes under pressure from commissions and rising fees.

We build custom booking and reservation apps for organisations that have reached that point. They are almost always businesses with multiple locations or a mixed offering (room + treatment + dinner + activity), with a way of working that generic SaaS platforms simply don't support: a fitness chain combining personal trainer slots with group classes and childcare, a hotel group selling rooms and spa treatments in one funnel, or a car rental company linking fleet availability to a loyalty programme for frequent renters.

The other reason organisations come to us is ownership. On a commission platform like Booking.com or Treatwell, you are not the customer but the supplier, and your most important customer data lives there rather than with you. Your own booking app gives you a direct relationship with your guest, client or patient, a direct payment flow without marketplace commission, and the data to make personalised offers and encourage repeat visits. For the booking layer we often work with a custom reservation system and connect directly to an in-house payment platform when your volume justifies it. For our broader approach to mobile projects, see our app development page.

Three types of booking app.

Which type fits depends on your offering, your inventory structure and how often your mechanics change. We determine what fits during the first conversation together. Often you start with a focused version and grow as the channel's volume picks up.

Compact project · fixed sprint budget

Single-resource booking app

The clean entry point for organisations with one type of inventory and a straightforward pricing structure. Customers see availability in real time, choose a slot, pay immediately with Mollie or Stripe and receive a confirmation with a calendar invite and wallet pass. A simple management environment in which staff can adjust opening hours, prices and blocks themselves without a release. Typical for hairdressers, beauty specialists, small fitness studios, escape rooms and sports trainers.

Real-time calendarMollie / Stripe + iDEALWallet passesReminders

Mid-sized project · fixed sprint budget

Multi-resource with waitlist and no-show fees

For organisations that combine several types of inventory in a single booking: a room plus a masseur, a practitioner plus a room plus equipment, a hotel room plus a spa slot, a coworking desk plus a meeting room. With waitlist functionality for popular slots, automatic no-show fees for customers who don't turn up, dynamic pricing at peak times and loyalty integration to reward repeat bookings. Typical for fitness chains, beauty salons with multiple practitioners, meeting venues and coworking spaces.

Multi-resourceWaitlistAutomatic no-show feeDynamic pricingLoyalty

Larger project · fixed sprint budget

Multi-location, multi-offering, multi-language platform

A complete booking ecosystem for chains with multiple locations and mixed offerings. PMS or till integration across all locations, group bookings for events or corporate clients, integration with an in-house payment platform for split payments, prepaid wallets and gift vouchers, a revenue management layer for dynamic pricing based on demand curves, and multiple language and currency options. Reporting for commercial, operations and finance teams is included as standard. Typical for hotel groups, hospitality brands, car rental networks and large fitness or wellness chains.

Multi-locationGroup bookingsRevenue managementMulti-languageGift vouchersPMS integration

What you get at the end.

A production-ready booking app, plus everything around it so you can run and expand it yourself. We do not deliver a black box: you own the code, the customer data and the release pipeline. We provide management only if you want it, and if the programme needs to move to another agency later, there is no legal or technical obstacle.

Mobile app for iOS and AndroidNative (Swift / Kotlin) or cross-platform (Flutter / React Native), depending on the mechanics required, the animation quality your brand demands and your internal capabilities. Branded with your colours, typography and motion language: not a template in which your organisation barely recognises itself.
Availability and booking engine in the backendA real-time engine on Postgres and Redis that handles slots, blocks, capacity and multi-resource combinations. Atomic booking transactions ensure you never get a double booking for the same slot, with an audit log for every action and repeatedly tested edge cases (last slot, concurrent requests, retry on payment failure).
Payment layer with Mollie or StripeiDEAL, Bancontact, credit card, Apple Pay, Google Pay, Klarna Pay Now and SEPA. For higher volumes we connect directly to an in-house payment platform, with a deposit flow for reservations, automatic no-show fees, split payments for group bookings and refund flows that fit your administrative reality.
Waitlist and no-show mechanicsCustomers can join a waitlist for popular slots and automatically receive a notification as soon as space becomes available. No-show fees are collected automatically based on the policy you set, with a fair appeals process so you don't damage customer relationships.
Dynamic pricing and revenue managementA pricing engine that recognises peak and off-peak hours, steers according to demand curves, and allows manual overrides for events or seasons. For hospitality environments we also integrate with external RMS platforms (Duetto, IDeaS, Atomize) if you already use them.
Loyalty and referral layerPoints or credits per booking, tiers for frequent customers, personalised offers at low-occupancy slots, and a referral flow with built-in fraud detection. We can link it to a custom loyalty app if you want to position the programme as a standalone offering.
Integrations with your stackPMS (Mews, Apaleo, Cloudbeds, Opera, Protel), POS (Lightspeed, Untill, Tally Pay, Toast, Storyous), calendars (Google Calendar, Outlook, Apple Calendar, iCal), marketing automation (Klaviyo, Mailchimp, Braze), CDP, ERP and finance. For industry-specific systems (Salonized, Treatwell, Mindbody, Eversports, Trainin, Resengo, Eveeno) we build the adapters so that migrating existing bookings doesn't become a big bang.
Multi-language and multi-currencyFor organisations with an international audience or Belgian-Dutch locations. Not just a translation layer for the UI, but also language-sensitive content (location descriptions, treatment descriptions, FAQs) that your marketing team manages itself without a release.
Reporting for operations, commercial and finance teamsDashboards on occupancy per location and resource, revenue per slot, no-show percentage, conversion path through the funnel, and customer lifetime value per segment. Exported to your BI tool if you already use one.
App store publication and launch supportGuidance through the App Store and Google Play, ASO basics, a launch checklist for marketing and a short training session for your location teams so that adoption at the front desk gets off the ground too.
Maintenance contract (optional)Monitoring, OS updates for iOS and Android, security patches and ongoing development. A fixed monthly fee, four response-time levels, no surprises.

Who we build booking apps for.

Ten sectors in which we support customers. If you recognise your organisation in one of them, we'd be happy to talk, even if you don't yet know whether a custom app is the right choice at your scale or whether it's better to take an intermediate step with an existing platform.

Hospitality

Hotel chains and boutique groups

Hotels with multiple room types, restaurant, spa and activities in one funnel. A direct-booking app that saves you commission on Booking.com, integrated with your PMS (Mews, Apaleo, Opera) for real-time availability and with a revenue-management layer for dynamic pricing. Often combined with an own hospitality website so the hotel and restaurant chain looks consistent throughout.

Fitness and wellness

Gyms, yoga, pilates, padel

Fitness brands that combine group classes, personal-trainer slots, childcare and wellness. With a waitlist for popular classes, no-show fees that feel fair, membership integration and loyalty tiers for frequent visitors. For chains with multiple locations, also location-independent booking: a member in Amsterdam can book a class in Utrecht without any hassle.

Hair & beauty

Hairdressers, nail bars, barbershops

Hairdressing and beauty brands with multiple practitioners per location. Clients choose treatment, practitioner and time, receive reminders and can easily rebook with the same practitioner. The custom work lies mainly in mechanics that platforms such as Treatwell or Salonized struggle to accommodate: combination treatments, recurring subscriptions, group bookings for weddings, or a loyalty integration with your own branded products.

Healthcare

Practices, clinics, allied health

Dental, GP, physiotherapy, psychology and independent medical practices. Alongside standard appointment booking, we offer intake forms with medical questions, reminders for follow-up appointments, and a data vault designed with GDPR and NEN 7510 in mind for patient data. Direct sync with practice management software (Intramed, Spotonmedics, Medicom, OmniHis) eliminates duplicate admin.

Restaurants

Fine dining, fast casual, restaurant groups

Restaurant concepts that want to go beyond Resengo or TheFork. Reservations with a deposit, no-show fees for non-attendance, table allocation within kitchen tooling, allergy questions passed straight through to the kitchen, and upselling of wine pairings or special menus during booking. For groups with multiple locations, we also offer overarching reservations with guest profiles that carry across sites.

Meeting venues

Meeting rooms, conference centres, event venues

Providers of meeting rooms, conference venues, day conferences and event locations. With multi-resource bookings (room + catering + AV package), availability that works down to the hour, and group bookings for multi-day events. Often integrated with your own invoicing flow and a quote mechanism for larger requests that can't be handled self-service.

Car rental

Rental companies and shared mobility

Car rental companies, van hire, campervan rental and shared mobility providers. Featuring real-time fleet availability, location selection, optional geo-tracking, deposit payment at booking, a damage protocol via the app and a loyalty programme for frequent renters. Flexible rates per day, week or season.

Sports trainers

Personal trainers, sports coaches

Personal trainers, physio coaches and sports instructors who work independently or in a small practice. Featuring personal schedules, location choice (at home, in a studio, outdoors), multi-session packages and a direct payment flow so sessions are paid in advance. Connects to fitness chain apps if the trainer is affiliated with a chain.

Coworking

Coworking, flexible workspaces

Coworking spaces and flexible workspace providers. With booking for desks by the day or half-day, meeting room reservations, lunch deals, membership integration and multi-location access. Often combined with access control (opening doors via the app), printer credits and coffee credits.

Escape rooms

Escape rooms and experience formats

Escape room and experience providers with group-based slots, dynamic pricing at peak times, gift vouchers with a gifting flow, and multi-room flows for corporate outings. Features capacity management so double bookings of the same group room are prevented, and a social-sharing mechanism after the experience for organic growth.

How a booking app project works.

Introduction

A conversation in which we work out which operational goal you want the app to hit (reducing commission, raising occupancy, restoring the direct relationship with the customer, lowering no-shows, increasing repeat visits), what your inventory looks like, which systems are already running, and where your current platform choice is hitting its limits. The sharper the commercial goal at the start, the less we have to correct along the way. A booking app without a clear goal soon becomes an expensive second diary.

Inventory design and flow architecture

A workshop with operations, commercial and (often) finance to pin down the booking mechanics: how slots are structured, which resources can be combined, how deposits and no-show fees work, which price curve fits, and how the waitlist behaves. Alongside this, a data workshop with IT to map which events come back from the PMS, the till and the marketing stack. At the end: a concrete scope, a mechanics specification, screen flows and clear agreements on what is and isn't included in phase one.

Building in sprints

A working build every two weeks on TestFlight and the Google Play internal track. We build the core first (account, slot selection, payment, confirmation) so operations can test whether the booking flow works before we layer on mechanics. After that come the waitlist, no-show fees, dynamic pricing, loyalty and multi-resource bookings. Availability and booking logic is tested automatically. A booking app that creates a double booking is worse than one that opens a little slowly: customers lose trust in the system, and your location team is left to pick up the pieces.

Soft launch and rollout

First a soft launch through one location or one customer cohort, then a wider launch with campaign support. From day one we monitor occupancy, no-show percentage, conversion through the funnel and early loyalty engagement, and steer where needed. Many clients plan a second release cycle straight after rollout to pick up feedback from active users. A booking app running in production inevitably generates new ideas.

Frequently asked questions.

What clients usually want to know before starting on a booking app.

What is the difference with Mews, Booking.com, Resengo or a comparable SaaS?

Mews, Apaleo, Cloudbeds (hospitality), Booking.com (marketplace), Resengo, TheFork (restaurants), Salonized, Treatwell, Eversports (beauty and fitness) and similar platforms are good at general mechanics. They reach their limits on four points. Firstly, industry- or format-specific logic: a hotel chain that wants to combine rooms and spa in one booking, or a fitness brand that links personal-trainer slots to childcare. Secondly, integrations with non-standard PMS, POS or CDP stacks where adapter work becomes expensive and fragile. Thirdly, commission and fee structures that make your best channel more expensive the better it performs. Fourthly, ownership of customer data: on a marketplace the guest remains their customer, not yours. We are also honest about when an off-the-shelf SaaS solution is enough: for a standard booking flow without exotic integrations, that can be a perfectly good first step.

Native or cross-platform: what do you recommend?

It depends on the mechanics and your internal capacity. For standard booking flows (slot selection, payment, reminders, loyalty), Flutter or React Native work very well and deliver simultaneous release on iOS and Android from a single codebase. For apps that rely heavily on hardware (Apple Wallet for passes, advanced push segmentation via OS features, NFC check-in at the counter, complex animations that carry the brand's feel), we increasingly choose native: Swift for iOS, Kotlin for Android. We advise case by case. We can deliver either route and do both well. For the web version of the app that you open in the browser (for example from a Google search result), we build a Progressive Web App that shares the same booking engine.

How do you handle PMS and till integration?

We integrate with all the common PMS and POS systems in the Benelux: Mews, Apaleo, Cloudbeds, Opera, Protel, RoomRaccoon and in-house PMS via our own middleware, plus the common POS systems (Lightspeed, Untill, Tally Pay, Toast, Storyous, Vectron, MplusKASSA, Square, Adyen POS stacks). The integration can work both ways: reading availability (real-time or via a cache with invalidation on change) and writing bookings (atomic, with retry logic on timeouts so that double bookings are ruled out). For industry-specific systems (Salonized, Treatwell, Mindbody, Eversports, Trainin, Resengo, Salonkee) we build the adapters so that migrating existing bookings doesn't have to be a big bang.

How do you handle payments, PSD2 and SCA?

Payments run through Mollie or Stripe as standard, and for larger volumes through a dedicated payment platform. We comply with PSD2 and Strong Customer Authentication (SCA) through 3D Secure 2.0 for card transactions, a native flow for iDEAL and Bancontact, and a frictionless flow where the PSP supports it. For recurring payments (subscriptions, no-show fees, repeat deposits), we use mandates with the right SCA exemption. Refund flows are covered by automated tests, because a refund error damages a customer relationship faster than an ordinary booking error.

How do you arrange no-show fees so they stay customer-friendly?

No-show fees solve a real operational problem, but they weigh heavily on the customer relationship if they go wrong. We build in three mechanisms. First, a grace period with an automatic reminder in advance, so the customer can still cancel or reschedule. Second, a transparent policy within the booking flow: the terms are visible before the customer pays, not buried in general terms and conditions. Third, a reasonable appeal route so that staff can reverse a no-show fee if the customer raises it with a good reason. Customers experience a fair system, and you keep operational capacity under control.

How do you handle GDPR and customer data?

Booking data is inherently sensitive: names, contact details, payment details and, in healthcare, medical context too. We build a GDPR-compliant opt-in flow for marketing communications, a granular consent model (you can book without receiving personalised offers), retention policies for customer and transaction data, and a data vault structure in which sensitive attributes are kept separate from operational data. For healthcare practices we add NEN 7510 practices (encryption at rest, an audit log for every access, pseudonymisation where possible, role-based access under BIG registration). We include a DPIA as standard in broader CDP projects. ePrivacy also applies to push notifications, which require a separate consent step.

What about the EAA and WCAG accessibility?

From 28 June 2025, a booking app falls under the European Accessibility Act (EAA), which sets WCAG 2.1 level AA as the minimum. We build accessibly from the start: correct contrast ratios, visible focus states, screen-reader labels on interactive elements, stock selection that works with keyboard navigation, and a booking flow that does not rely on timeout buttons. For sector-specific requirements (healthcare, government) we go beyond AA where necessary. We carry out an accessibility audit at the end of the project and deliver an accessibility statement that you can publish on the site.

How do we prevent duplicate bookings for the same slot?

Double bookings almost always arise from a race condition: two customers book the exact same slot at the same moment for the last available place, and the back end accepts both. We solve this with atomic booking transactions on the database (Postgres advisory locks or row-level locking), combined with a queueing mechanism for peak moments such as a popular group class or a busy dinner slot. The booking engine guarantees that a slot can be taken at most once, regardless of how many customers press the "confirm" button at the same time. Automated tests cover these edge cases, so regressions cannot reach production.

What about gift cards and the Dutch Gift Card Act (Cadeaubonwet)?

If you issue gift cards for bookings — dinner vouchers, spa vouchers, escape room gifts, fitness passes — specific rules apply in the Netherlands regarding validity (a minimum of two years since 2023), information obligations, disclosure of the remaining balance, and the position on loss or expiry. We make sure the redemption flow complies with these requirements, and for larger programmes we explicitly involve a legal specialist — so there are no surprises later on in a first discussion with a regulator.

Does the app work offline?

For viewing confirmations, calendar entries and wallet passes, working offline is usually not critical, as the booking is made on the customer's side with internet access. For staff tools at the front desk or in a meeting room without coverage, we have built offline-friendly flows: the staff app caches booked slots locally, guests can be checked in without a connection, and changes sync as soon as the network is back. This matters especially in older buildings, basement locations or hospitality venues with thick walls where Wi-Fi is unreliable.

How do you measure whether the app works commercially?

We set up reporting on occupancy by location and resource, revenue per slot category, no-show percentage, conversion through the funnel (from app open to confirmation), customer lifetime value per segment, and commission savings if you migrate from a marketplace. For more mature programmes, we also build in A/B tests on price points, slot presentation and upsell flows, so you know not only whether the app works but also which variant performs best for which segment. Reporting goes to your BI tool if you already use one, or appears as a dashboard in the app's own admin.

Who owns the code, customer data and booking history?

You do. We deliver the complete source code, schemas, build pipelines and deployment scripts. The data resides in your cloud (GCP, AWS, Azure) or with a hosting provider of your choice. If you later want to continue with another agency, or take things over in-house, you can — there is no technical lock-in, no hidden API keys, and no subscription to something you no longer want. We earn our keep through good work that lasts, not by keeping clients locked in.

What determines the cost of a booking app?

The main cost drivers are the complexity of the booking mechanics (single-resource versus multi-resource with capacity and waitlists), the number of integrations (PMS, point of sale, calendar, CDP, marketing automation, ERP, finance), the degree of personalisation and revenue management (static prices versus a dynamic pricing engine), the number of locations and languages, and whether native or cross-platform is the right choice for your brand. In addition, sector-specific compliance requirements (healthcare, financial) play a role. We work in sprints with fixed sprint budgets, so you are not faced with surprises and can steer scope on a sprint-by-sprint basis.

How long before we can go live?

A first working version with slot selection, payment and confirmation can be live on TestFlight and in the Google Play internal track within a number of sprints. A full platform with multi-resource booking, waitlists, no-show fees, dynamic pricing, loyalty and multi-location integration takes several sprints. We often roll out in phases, so a single pilot location can start while we continue building. We feed that feedback in directly before the wider launch.

Talk to us about your booking app.

A free, no-obligation half-hour introductory call. Tell us what's going on now: the platform you're struggling with, the mechanics your SaaS can't handle, or the commission pressure you want to get rid of. We'll think it through with you, give direction, and be honest about whether a custom app is the right choice or whether an interim step with an existing platform suits you better. We'll also say so if we think you'd be better served by a SaaS product we don't build. If you'd rather email directly, reach us at fabian.vandijk@appfront.nl, or browse our other app development service pages for related mobile solutions.

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