Custom software or off-the-shelf SaaS: how to choose
Custom software or an off-the-shelf SaaS product? Cost, timescale, fit, data and lock-in compared, plus the hybrid approaches that work well in practice.
5 min read
Software development · Ajaccio, Corsica
Web application development, from portal to SaaS
A web application runs in any browser, with nothing to install. From Ajaccio, Corsica, Step By Step builds client portals, extranets, dashboards and SaaS platforms, with fast React or Vue interfaces, a documented API and data hosted in France.
- React
- Vue
- GraphQL
- PostgreSQL
- Supabase
- Docker
- Desktop, tablet, mobile
- Every screen
- A browser is all it takes
- Nothing to install
- For every user at once
- Instant updates
- Accounts and role-based rights
- Secure access
What we build
Which web application does your business need?
A custom web application meets a precise need: giving customers access, organising an internal process or launching a new online service. These are the most common cases.
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Client portal
Customers track orders, download documents, sign quotes and message you from a secure personal space.
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Partner extranet
Suppliers, resellers or subcontractors see the information that concerns them: catalogues, price lists, schedules and purchase orders.
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Dashboard
Your key indicators gathered from several sources, with filters, charts and exports, updated automatically.
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SaaS platform
You have an online service to sell: we build the platform, subscriptions, multi-company accounts and back office.
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Booking and scheduling
Online calendar, availability management, automatic reminders and deposits: an application shaped around your organisation.
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Forms and workflows
Internal requests, multi-step approvals and sign-off circuits: paper processes turned into traceable digital journeys.
Choosing well
Website or web application: what is the difference?
A website presents your business to anonymous visitors; a web application lets signed-in users get things done. Many projects combine both.
| Criterion | Showcase website | Web application |
|---|---|---|
| Purpose | Present the business, generate enquiries | Let users get tasks done |
| Users | Anonymous visitors | Signed-in accounts with different rights |
| Content | Pages and articles | Data, forms, documents, calculations |
| Technology | Static site generator or CMS | React or Vue, API, database |
| Search ranking | Essential | Only useful for public pages |
Mainly looking to present your business? See our website creation page.
Technology
The technologies behind our web applications
We build web applications with modern, standard and widely adopted technologies, so they stay fast, secure and easy to evolve for years.
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React and Vue
Responsive interfaces that react instantly, even with large amounts of data.
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PostgreSQL and Supabase
A robust relational database, with backups and row-level access rights.
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REST and GraphQL APIs
A documented API to connect your application to your software and to a future mobile app.
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Docker and serverless
Reproducible deployments on servers hosted in France or on serverless functions.
- Accessible, responsive interfaces, tested on mobile
- Secure authentication, with optional two-factor sign-in
- Automated tests and versioned deployments
Method
How we run web application development
Web application development happens in short iterations. You use the application in a staging environment from the first weeks and steer the priorities.
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Journeys and mock-ups
Who uses the application, to do what, in which order: we map the journeys and then the screens with you.
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Architecture
Data model, roles and permissions, required integrations and hosting choices.
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Iterative development
Releases deployed to a staging environment that you actually use at every stage.
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Go-live
Deployment, monitoring, automatic backups and training for administrators.
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Evolution
New features, new user types or a companion mobile app: the platform grows with you.
First call on us
A portal, a SaaS or an internal tool to build?
Tell us who the users are and what they need to do: we will come back with a proposed architecture and a phased plan.
Development section
Our other development services
- Custom software ERP, CRM, HR, management tools: business software built around your processes.
- Mobile apps iPhone and Android apps, native or cross-platform with Flutter.
- Website creation Fast, well-ranked showcase websites that are easy to evolve.
- E-commerce websites Online shops connected to your till, stock and accounting.
- AI integration Large language models connected to your software, CRM or ERP.
Blog
Further reading: our articles on the topic
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Flutter, React Native or native: choosing the technology for your mobile app
Flutter, React Native, Swift and Kotlin: strengths, limits and the criteria that matter when building your iPhone and Android app in 2026. A clear guide.
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FAQ
Frequently asked questions about web application development
What is a web application?
A web application is software used through an internet browser, with nothing to install. Unlike a showcase website that presents information, it lets signed-in users carry out tasks: entering data, tracking orders, approving requests or viewing dashboards.
What is the difference between a web application and a mobile app?
A web application runs in the browser on every device and updates instantly for everyone. A mobile app is installed from the App Store or Google Play and makes better use of the phone: notifications, offline mode, camera. Both can share the same API and database.
Can Step By Step build a SaaS product?
Yes. We build complete SaaS platforms: sign-up, subscription and payment management, isolated multi-company accounts, an administration back office and an API. We also help you define a first sellable version so you can test your market quickly.
Will our web application be secure?
Security is part of the architecture: strong authentication with optional two-factor sign-in, role-based permissions enforced on the server, encrypted traffic, protection against common web attacks, logging of sensitive actions and backups hosted in France.
Can a web application work offline?
Partly. A progressive web app can cache data and accept entries offline, then synchronise. For heavy use without a network, a dedicated mobile app remains more reliable, and we can build it on the same API.
Can you modernise an old web application?
Yes. After auditing the code and data, we propose either a gradual modernisation of what exists or a new application that takes over the old data. Either way, the transition is planned so your users can keep working.