Custom Next.js vs Power Apps for Internal Tools: London 2026 Comparison

The verdict in three sentences

For an internal app used by 400 people, Power Apps licences at about GBP 16 per user per month come to roughly GBP 76,800 a year, close to GBP 384,000 over 5 years. A custom Next.js build costs GBP 38,000 to 76,000 upfront, then GBP 7,000 to 13,000 a year, and becomes clearly cheaper from year one at this scale. Power Apps keeps the edge for small tools under 50 users or quick prototypes.

The need: purchase requests for 700 employees

The CIO of a manufacturer in London must replace a paper and e-mail process for purchase requests: entry by requesters, two or three approval levels depending on amount, budget checks, handover to procurement then the ERP. About 400 users create or approve at least one request a month, for 12,000 requests a year. The company already runs Microsoft 365, which makes Power Apps tempting.

Five-year total cost: where the break-even sits

The calculation below uses a median scenario: Power Apps build at GBP 27,000 and maintenance at GBP 7,500 a year; custom build at GBP 57,000 and GBP 10,000 a year. Licences are assumed flat, which is optimistic given vendors' regular price rises.

At 400 users, custom is cheaper from the first year. The break-even sits around 60 to 80 users: below that, Power Apps licences stay competitive, especially since some users may already hold rights through other Microsoft licences. Check your Microsoft agreement before deciding, as negotiated discounts change the maths.

At Kolonell, a purchase request app with multi-level workflow and ERP connector falls within our custom range of 2.5 to 15M+ FCFA (EUR 3,810 to 22,870+) depending on complexity; ERP and Entra ID integration is quoted separately. These figures are 2026 estimates.

Beyond price: lock-in, governance and scalability

Power Apps makes it easy for business teams to build apps, but that freedom often produces dozens of undocumented apps IT must then govern. Delegation limits on data sources force workarounds once lists pass a few thousand rows. By contrast, a Next.js app backed by PostgreSQL signs users in via Entra ID SSO, deploys on the hosting the company chooses (UK data centres for UK GDPR comfort) and stays maintainable by any TypeScript team. Reversibility is total: the source code belongs to the company.

Mini case study

Tom, CIO of the manufacturer in London, compares two quotes. Power Apps option: GBP 27,000 build, then GBP 76,800 in licences and GBP 7,500 maintenance a year. Next.js option: GBP 57,000, then GBP 10,000 a year. Over 5 years the gap reaches GBP 341,500. Tom keeps Power Apps for two small internal tools with 25 users already covered by existing licences, and picks custom for purchase requests. The annual saving from year 2 (GBP 74,300) funds a second application project.

FAQ

Is Power Apps included in Microsoft 365?

A limited version is, but Premium connectors (SQL, ERP, external APIs) and Dataverse need a dedicated licence, around GBP 16 per user per month in 2026.

How long does the custom app take to deliver?

Allow 3 to 4 months for the full workflow, budget checks and ERP connector, versus 6 to 10 weeks for an equivalent Power Apps version.

Can we move from Power Apps to custom later?

Yes, but the logic must be rewritten: only the data is reusable. A migration often costs 70 to 90% of a fresh build.

Does custom need an in-house team?

No. A maintenance contract of GBP 7,000 to 13,000 a year covers fixes, security updates and small changes.

What about fewer than 50 users?

Power Apps is often the more rational choice, especially if users already hold the needed rights. Custom is then justified by specific UX or integration needs.

Let's scope your project. Tell us your user count, current Microsoft licences and the process to digitize: we will price both options, an indicative budget and the 5-year cost. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.