The verdict in three sentences
A solid requirements document for a B2B room booking platform fits in 25 to 40 prioritised functional requirements, not 80 pages of wishes. For a network of 4 business centres in Amsterdam, the development budget sits between 30,000 and 55,000 EUR (excl. VAT) for a timeline of about 12 weeks. The goal to write down is commercial: lift room occupancy toward 65 %, compared with the 40 to 45 % often seen when bookings go through phone and email.
Requirement blocks and their budget weight
The operator of an Amsterdam network (Zuidas, Sloterdijk, Amstel, Noord) rents rooms for 4 to 20 people by the hour, half day and day. Clients are companies that book for several employees and want a single monthly invoice. The requirements document is organised in blocks, each with a requirement count and an estimated cost.
| Functional block | Typical requirements | No. of requirements | Indicative 2026 cost (EUR) |
|---|---|---|---|
| Room catalogue | Capacity, equipment, photos, rates per slot | 4 to 6 | 3,500 to 6,000 |
| Booking engine | Real-time availability, recurrence, add-ons (coffee, lunch) | 6 to 9 | 7,500 to 12,500 |
| Company accounts | Multi-user, spending caps, manager approval | 4 to 6 | 5,000 to 8,500 |
| Payment and invoicing | Card and iDEAL (Stripe), monthly invoicing, credit notes | 4 to 6 | 5,000 to 10,000 |
| Calendar sync | Outlook (Microsoft 365) and Google Calendar | 2 to 4 | 3,500 to 7,000 |
| Centre back office | Schedule, cleaning, access, dynamic pricing | 3 to 5 | 3,500 to 7,000 |
| Reporting | Occupancy per room, revenue per client, accounting export | 2 to 4 | 2,000 to 4,000 |
The low end covers a scope without dynamic pricing or manager approval; the high end includes monthly invoicing with export to accounting software and two-way calendar sync.
Non-functional requirements not to forget
Failed requirements documents describe screens well and forget the rest. These are the requirements that prevent surprises during acceptance testing.
| Requirement | 2026 target value | Why |
|---|---|---|
| Availability display time | Under 1 second | A client who waits books elsewhere |
| Platform uptime | 99.5 % monthly | Bookings happen evenings and weekends |
| GDPR compliance | EU hosting, processing register, retention periods | Client employees' data |
| Payment | 3-D Secure (PSD2), no card stored in clear | Regulatory obligation |
| Accessibility | WCAG 2.1 AA, in line with the European Accessibility Act | Large accounts and public clients |
| E-invoicing | Peppol-ready UBL format | Dutch public buyers and large accounts already require it |
The European Accessibility Act has applied since June 2025 to many consumer-facing digital services, and Peppol e-invoicing is standard with Dutch public bodies: writing both into the requirements avoids costly retrofits.
Build, buy or adapt: the comparison
| Option | Upfront cost | Annual cost | Monthly company invoicing | Fits 4 centres |
|---|---|---|---|---|
| Custom platform | 30,000 to 55,000 EUR | 4,800 to 9,600 EUR (maintenance) | Yes, on your rules | Yes |
| Coworking SaaS software | 500 to 2,500 EUR | 6,000 to 14,000 EUR | Partial, depends on vendor | Yes, with limits |
| Booking plugin on brochure site | 1,000 to 4,000 EUR | 300 to 800 EUR | No | Hardly |
| Room marketplaces | 0 EUR | 15 to 25 % commission per booking | Handled by the marketplace | Yes, but client not owned |
SaaS is the right answer to start fast. Custom becomes relevant when company invoicing, pricing rules and the direct client relationship are part of the competitive edge, which is the case for a 4-centre network targeting recurring accounts.
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Sanne, managing director of a 4-centre business network in Amsterdam (illustrative persona), runs 22 rooms available 10 hours a day over 21 working days, or 4,620 sellable hours per month. Her occupancy is 42 % at an average price of 34 EUR per hour, or 65,970 EUR of monthly revenue. Moving to 55 % through online booking and company accounts adds 600 hours sold, or 20,400 EUR per month. A platform at 45,000 EUR plus maintenance of 600 EUR per month pays for itself in under three months of that extra revenue, before even reaching the 65 % target.
FAQ
How many requirements should the document contain?
Between 25 and 40 functional requirements prioritised with MoSCoW are enough for a first 12-week release. Beyond 50, the project almost always slips in time and budget.
What budget for a B2B meeting room booking platform in Amsterdam?
Plan 30,000 to 55,000 EUR for custom development, plus 400 to 800 EUR per month for maintenance. Monthly invoicing of company accounts often represents 15 % of the budget.
Is Outlook and Google sync essential?
For a business clientele, yes: it prevents double bookings and no-shows. Budget 3,500 to 7,000 EUR depending on one-way or two-way sync.
Should e-invoicing be included from 2026?
Yes, if you serve public bodies or large accounts. Peppol UBL invoices are already expected by Dutch government buyers, and the EU ViDA package extends e-invoicing obligations in the coming years.
How long to launch the platform?
About 12 weeks of development after a 2-week scoping phase. A one-month pilot in a single centre lets you adjust pricing before opening all 4 sites.
Let's scope your project. Share your number of centres and rooms, your invoicing rules and your target date, and we will turn your need into a prioritised requirements document with an indicative budget and schedule. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
