Choosing between a website, a platform and an app: the decision tree

Five questions that decide whether you need a website, a logged-in platform or a mobile app, and what each choice commits you to.

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The short answer

Businesses are sold apps and platforms when they need websites, and occasionally the reverse. Five questions sort it out. Who uses it, and are they logged in? What do they actually do: read, contact, buy, or create and manage data? Does it need device features or to work offline? How often does the same person return? What must it connect to? The answers lead to one of three things. A fast website, which covers most needs. A website with a logged-in area or a full platform, which covers many. A mobile app, which covers few, and those few usually start as one of the others. Each choice commits you to a cost shape: a website is cheap to run, a platform has running and maintenance costs, an app adds stores, platforms and annual updates. The tree is designed to stop you building the most expensive thing on the least evidence.

The decision tree

QuestionAnswerPoints to
1. Are users logged in?No: they read, contact, book, buyWebsite
Yes, to see their own information and do a few thingsWebsite with a logged-in area
Yes, and managing data is their main activityPlatform
2. What do they do?Read and decideWebsite
Transact once in a whileWebsite with checkout or booking
Create, change, manage, collaboratePlatform
3. Device features or offline?NoWebsite or platform
Camera, sensors, offline capture, notifications everywhereApp, often a progressive web app first
4. How often does the same person return?OccasionallyWebsite or platform in the browser
Daily, and they want an iconProgressive web app; native if features demand
5. What must it connect to?Nothing, or a form and emailWebsite
Business systems, payments, data flowsPlatform with integrations; an app shares its back end

What each commits you to

  1. A website: content, design, hosting that is near free, monthly maintenance that is light. Fast to build, cheap to run, easy to leave.
  2. A website with a logged-in area: the above plus authentication, a small back end and data, with maintenance to match.
  3. A platform: an application: back end, database, integrations, roles, monitoring, a maintenance contract, a change budget, and a team who owns it.
  4. An app: everything a platform needs plus the front ends, store publication, device testing and the annual update cycle. The most expensive shape, justified by device features, offline or daily use.

Starting small on purpose

A website first establishes content, audience and the back end that any later stage reuses. A logged-in area next proves what customers want to do when signed in. A platform follows if managing data becomes their main activity. An app comes last, if device features, offline or daily use demand it, building on a back end and a use case that already exist. Each stage is cheaper than the next and produces the evidence the next one needs.

What this means for you

Answer the five questions about real use, choose the smallest shape that delivers the outcome, and know the cost shape you are committing to. A business needs a fast website; some need a logged-in area; an app is the rare case, and those should arrive last, built on evidence. The decision tree exists to keep the money on what customers will actually use.

Written by the CivSec S.M.A.R.T team

We build and run websites, software and AI systems for businesses. We write about what we see in that work, in plain language, and we update articles when things change.

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Frequently asked questions

Our competitor has an app. Do we need one?

Only if your customers would do something in it that they cannot do on a fast mobile website, such as work offline, use device features, or return daily enough to want an icon. The competitor app you are being shown was installed once and forgotten. Ask what your customers would actually do in yours; the answer decides, not the competitor.

What is the difference between a website with a login and a platform?

Scale and state. A website with a login area shows a customer their information and lets them do a few things. A platform is software where logged-in users create, change and manage data as their main activity, with roles, workflows and integrations. The first is a website with a small dynamic part; the second is an application and is built and maintained as one.

Can we start with a website and add an app later?

Yes, and it is usually the right order. A website establishes the content, the audience and the back end. A logged-in area proves what customers want to do. An app, if needed, then builds on a back end that exists and a use case that is understood. Starting with the app builds the most expensive thing first on the least evidence.