The verdict in three sentences
For an Amsterdam letting agency managing 2,300 units, rebuilding the whole accounting core (rent invoicing, landlord accounts, client money segregation) as custom software is expensive and adds almost nothing distinctive. The value lies in the landlord and tenant portals, service charge reconciliation and automated reminders, where packages stay rigid. The winning scenario in 2026 is a market package + 15,000 to 40,000 EUR of custom modules, connected through an API.
Package, custom or hybrid: the 2026 figures
Property management vendors in the Netherlands charge per managed unit, typically 4 to 10 EUR per unit per month in Amsterdam. For 2,300 units, the gap between entry level and premium is large, and this recurring cost is what you must compare with a custom investment.
| Option | Upfront cost | Annual cost (2,300 units) | 5-year cost | Go-live time |
|---|---|---|---|---|
| Entry-level package (4 EUR/unit/month) | 3,000-8,000 EUR data migration | 110,400 EUR | approx. 560,000 EUR | 2-3 months |
| Premium package (10 EUR/unit/month) | 10,000-25,000 EUR | 276,000 EUR | approx. 1,400,000 EUR | 3-5 months |
| Mid-range package (6 EUR/unit/month) + custom modules | 15,000-40,000 EUR | 165,600 EUR + 6,000 EUR maintenance | approx. 880,000 EUR | 3-4 months |
| Full custom | 50,000-120,000 EUR | 12,000-24,000 EUR (hosting, support) | 110,000-240,000 EUR | 8-12 months |
| Status quo (spreadsheets + legacy package) | 0 EUR | 60,000 EUR estimated lost time | 300,000 EUR | / |
Full custom looks unbeatable over 5 years, but the estimate ignores two real risks: client money accounting must be flawless from month one, and every regulatory change (the Dutch Affordable Rent Act points system, energy labels, annual rent indexation caps) becomes your burden. For an agency that does not want to become a software vendor, hybrid remains the best risk/value ratio.
What the custom modules should cover
Packages handle rent invoicing and accounting well. They handle client experience and the repetitive tasks specific to your organisation poorly.
| Custom module | Indicative budget | Measurable gain | Regulatory constraint |
|---|---|---|---|
| Landlord portal (statements, documents, tax reports) | 8,000-15,000 EUR | -40% inbound calls | Transparency towards the landlord |
| Tenant portal (receipts, payment, maintenance requests) | 6,000-12,000 EUR | -30% property manager e-mails | Free rent receipts |
| Automated service charge reconciliation | 5,000-10,000 EUR | 3 days saved per cycle per manager | Annual statement within 6 months |
| Maintenance ticketing + contractors | 4,000-8,000 EUR | Response time -35% | Quote traceability |
| Multichannel arrears reminders (SMS, e-mail, letter) | 3,000-6,000 EUR | Arrears from 3.5% to 2.2% | Legal steps before collection |
| Management dashboard (vacancy, yield per mandate) | 4,000-9,000 EUR | Weekly steering | / |
All these modules read and write into the package through its API or scheduled exports. Before signing, demand written API documentation and a test environment from the vendor: it is the first selection criterion.
The traps of a property management project
Three issues derail projects in Amsterdam as anywhere else. Data migration first: 10 years of rent history, deposits and landlord statements migrate badly, plan 10 to 20 days of checks. Access rights next: a landlord co-owning 4 units must only see their share, an owners' association only its buildings. Finally GDPR compliance: applicant ID copies and income documents cannot be kept indefinitely, and the purge must be automatic.
Mini case study
Sanne runs a letting agency in Amsterdam (2,300 units, 9 property managers) and pays 5 EUR/unit/month today, or 138,000 EUR a year, for a package with no decent portal. Each manager spends 6 hours a week on the phone with landlords asking for their statements.
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She keeps the package and orders a landlord + tenant portal plus service charge reconciliation: 28,000 EUR. Calls drop by 40%, or 2.4 hours per manager per week, so 9 × 2.4 × 45 weeks = 972 hours a year. At 45 EUR fully loaded, that is 43,700 EUR a year. The project pays back in under 8 months, and the agency can absorb 300 more units without hiring.
FAQ
Is full custom more profitable over 5 years?
On paper, yes: 110,000 to 240,000 EUR versus 550,000 EUR or more on a package for 2,300 units. In practice you must add continuous regulatory updates and accounting risk, which reserves it for agencies above 5,000 units.
How long to deliver the portals?
Allow 8 to 12 weeks for a landlord and tenant portal connected to the package, testing included. Migrating historical documents adds 2 to 3 weeks.
Is a portal legally required?
No, but transparency towards landlords and free rent receipts for tenants are expected. A portal reduces repetitive requests by 30 to 40%.
What happens if we change package?
If the custom modules go through a dedicated integration layer, only the connector needs rebuilding, about 3,000 to 8,000 EUR. That is why business logic should never be coded directly into the vendor's database.
Can we add online rent payment?
Yes, through SEPA direct debit, iDEAL or card via a licensed payment provider, for about 0.3 to 1.4% per transaction. The module plugs into the tenant portal for 2,000 to 4,000 EUR.
Let's scope your project. Portals, service charge reconciliation or full integration around your package: we price a precise scope, between 15,000 and 40,000 EUR depending on modules, delivered in 3 to 4 months. 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.
