Custom Client Portal Development Cost in 2026

The verdict in three sentences

A custom client portal costs 35,000 to 85,000 EUR ex. VAT in 2026 depending on functional scope, delivered in 12 to 18 weeks. Below 50-80 internal users a rented SaaS block stays cheaper; beyond that, or as soon as you need ERP integration and data ownership, custom becomes profitable. The real payoff is not cosmetic: it is the 20-30 % drop in support emails and the end of untraceable file exchanges by mail.

How much a custom client portal costs

Price depends on the number of modules and depth of integration. Here are the 2026 ranges observed for a services SME (order of magnitude).

The cost drivers: SSO (SAML/OIDC to your directory), documented GDPR compliance (register, DPA, erasure), and each custom ERP/billing connector (3,000 to 9,000 EUR per integration).

Custom build or rented SaaS block

The question is arithmetic, not ideological. A client-portal SaaS block rents for 49 to 199 EUR/month per internal user in 2026.

For 20 internal users at 99 EUR/month, SaaS costs 23,760 EUR/year. Custom, once amortized, runs around 12,000-18,000 EUR/year. The tipping point is around 14-20 months.

Mini case study

Marc, CIO of a 60-person services SME in Rennes, manages 400 active clients. His teams receive on average 1,800 support emails a month (invoice chasing, document sending, project status). He picks a standard portal at 58,000 EUR ex. VAT, delivered in 15 weeks.

After 4 months the portal absorbs 25 % of emails, i.e. 450 emails avoided/month. At 6 minutes average handling, that frees 45 hours/month, about 2,100 EUR/month of agent time (loaded cost 47 EUR/h). Over a year: 25,200 EUR saved, plus 11,000 EUR of SaaS licenses avoided. Payback lands around month 18, ahead of an asset he owns.

FAQ

How long to deliver a client portal? Expect 12 to 18 weeks in 2026 depending on modules and integrations. An essential portal (documents + invoices) can ship in 12 weeks; add 3 to 4 weeks per complex ERP integration.

Is SSO essential? Not for a simple external portal, but as soon as your staff uses it daily, SSO (SAML/OIDC) removes password management and hardens security. Budget 4,000 to 8,000 EUR for its integration.

How is GDPR compliance guaranteed? EU hosting, encryption at rest and in transit, processing register, erasure policy and DPAs with subprocessors. This foundation is about 5-8 % of the project budget but avoids sanction risk.

Can we start small and expand? Yes, and it is recommended: ship the highest-traffic module first (documents or invoices), measure usage, then add tickets and project tracking. Each added module costs 8,000 to 20,000 EUR.

What maintenance budget should we plan? Count on 15 % of build cost per year for maintenance, plus managed hosting (8,000 to 18,000 EUR/year), i.e. roughly 20,000 to 30,000 EUR/year for a standard portal.

Let's scope your project. Tell us your priority modules (documents, tickets, invoices, SSO), your client volume and your ERP, and we quote build and maintenance. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.