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WordPress powers more than 40% of all websites (W3Techs) — but "WordPress or custom?" is the wrong question. WordPress can host a site set up on a ready-made theme just as well as a site coded entirely for your business. The real comparison is between a WordPress site on a ready-made theme and a full-code website: 100% hand-coded development, in Next.js or in WordPress with a theme built from scratch for your site. Agence Zen builds full-code websites with both technologies; this guide explains the differences, the costs, and how to choose.
WordPress: One CMS, Two Ways to Build a Site
WordPress is a CMS (content management system) that started as a blogging tool in 2003. It manages your content; what your visitors actually see, and the code behind it, comes from the theme. There are two ways to build that part:
- A ready-made theme — bought or downloaded from a marketplace, designed to suit thousands of businesses, then customised with your logo, colours and texts
- A theme built from scratch — hand-coded for your site, with only the code it needs
The first is what most people mean by "a WordPress site". The second is full-code development, just like a Next.js site.
What WordPress Does Well
- A familiar admin interface — Many teams already know how to edit pages and publish articles in it
- A large plugin ecosystem — WooCommerce for e-commerce, forms, multilingual, and much more
- Community support — Extensive documentation and a large pool of developers
- Content editing — Non-technical users can update texts and images on their own
Where Ready-Made Themes Fall Short
- Performance — A theme built to cover every use case loads code for features you don't use; fast pages are possible, but harder to achieve and to keep
- Dependency — Your layouts and some features are tied to the theme: switching themes often means reworking the pages
- Stacked plugins — Each missing feature is filled by another plugin: more updates to follow, more conflicts, a larger attack surface
- Technical SEO — Heading structure, markup and structured data are constrained by the theme's code
- Generic look — The same themes are used by thousands of sites, sometimes your competitors'
Full Code: Next.js or WordPress With a Theme Built From Scratch
A full-code website is 100% hand-coded for your business: every page, every component and every line of code is written for your site and its goals. At Agence Zen, we build it with one of two technologies, depending on your needs:
- Next.js (React) — for the fastest sites and app-like features
- WordPress with a theme built from scratch for your site — you keep the WordPress admin you already know
In both cases, design, code and SEO/GEO are custom, you own everything (code, design, content, accounts), the price grid is the same, and a Google speed score of 90+ on mobile is guaranteed at launch.
Head-to-Head Comparison
| Criteria | WordPress on a ready-made theme | Full code (Next.js or WordPress) | Advantage |
|---|---|---|---|
| Performance | Depends on the theme and plugins; unused code still loads | Only the code the site uses; speed score of 90+ on mobile guaranteed at launch (Agence Zen) | Full code |
| Design | Limited by the theme's layouts and options | Designed for your brand | Full code |
| Security | Attack surface grows with each plugin and how well it is kept up to date | Dependencies limited to what is needed, kept up to date | Full code |
| Maintenance | Frequent theme and plugin updates, risk of conflicts | Included for 12 months, then €89/month | Full code |
| Technical SEO & GEO | Possible with plugins, constrained by the theme's code | Structure, markup and structured data built into the code | Full code |
| Content editing | WordPress editor, within the theme's layouts | WordPress admin or a simple editing interface (Next.js) | Both |
| Initial cost | Lower: a few hundred to a few thousand euros | Higher: from €3,200 at Agence Zen | Theme |
| Changing later | New theme = pages to rework | You own the code and evolve it step by step | Full code |
3-Year Total Cost Breakdown
| Cost Item | WordPress on a ready-made theme | Full code, Agence Zen (Next.js or WordPress) |
|---|---|---|
| Initial build | A few hundred to a few thousand euros | €3,200-6,400 |
| Hosting (3 years) | Separate subscription, depending on the host | €2,136 (12 months included, then €89/month incl. maintenance) |
| Theme and plugin licences | Annual renewals, depending on the theme and plugins | The code is yours: no theme licence to renew; any third-party subscriptions in your name |
| Security and updates | Your job, or a separate contract | Included in the care plan |
| Performance | Fixes often billed separately | Speed score of 90+ on mobile guaranteed at launch |
| Total over 3 years | Variable, spread across several providers | €5,336-8,536 |
Net prices — VAT not applicable (French micro-enterprise, art. 293 B CGI).
These are the Essentiel and Signature plans; the price is the same whether your site is built in Next.js or in WordPress. To estimate your own project, try our website cost calculator.
Decision Matrix: Which Is Right for You?
| Your Situation | WordPress on a ready-made theme | Full code |
|---|---|---|
| Budget | A few hundred euros, built yourself | From €3,200 (design, content and SEO made for you) |
| Role of the site | Simple online presence, testing an idea | Primary business development tool |
| Performance priority | Not critical | Core requirement |
| Differentiation | A look close to your competitors is fine | Your brand has to stand out |
| Maintenance | You handle updates and plugins yourself | You would rather delegate it |
When a Ready-Made Theme Is Enough
- Very tight budget and you build the site yourself
- Temporary site, or testing an idea before investing
- Very standard needs, where differentiation doesn't matter much
- You know WordPress well and are ready to maintain it yourself
When to Choose Full Code
- Your site is your main source of leads
- Performance and SEO are business requirements, not options
- You want a design that stands out from competitors
- You would rather not deal with updates and security yourself
- You want to own a site that can evolve without being rebuilt
Next.js or Hand-Coded WordPress: Which One to Choose?
Once full code is the right answer, the technology depends on how you will edit your content and on the features you need.
Choose WordPress with a theme built from scratch if…
- You want the WordPress admin to edit your pages and publish your articles
- You need the plugin ecosystem: WooCommerce, forms, multilingual
- Your team already knows WordPress
Choose Next.js if…
- You want maximum performance and security
- You need custom features close to an application (customer area, configurator, booking with payment)
- You want a simple editing interface, with no plugins to maintain
- Your site is multilingual or handles high traffic
In both cases: custom design, code and SEO/GEO, full ownership, and the same performance guarantee. We recommend one or the other during the discovery call, based on your project, not on a preference of ours.
Not sure which to choose?
We recommend the approach that fits your goals and your budget.
Let's discuss your project on a 30-minute discovery call with the founder.
30-min video callfreeno commitment
Valentin HalgandFounder and project director
Total Cost of Ownership: 5-Year Comparison
The initial price tag tells only half the story. Over 5 years, maintenance, licences, security, performance and design changes weigh as much as the build itself:
| Cost Category | WordPress on a ready-made theme | Full code (Agence Zen) |
|---|---|---|
| Initial build | A few hundred to a few thousand euros | €3,200-6,400 |
| Hosting & maintenance | Hosting subscription, maintenance often billed on top | 12 months included, then €89/month |
| Licences | Premium theme and plugins, renewed every year | The code is yours: no theme licence |
| Security updates | To schedule and pay for separately | Included |
| Design changes | A new theme often means reworking the pages | The existing code evolves step by step |
| 5-Year Total | Variable, hard to predict | €7,472-10,672 |
The takeaway: on paper, a site on a ready-made theme is often cheaper, but its costs are scattered (licences, updates, performance fixes) and its results depend on how well it is maintained. A full-code website costs more upfront; in return, performance, security, maintenance and SEO are part of the package, whether it runs on Next.js or on WordPress. The right comparison isn't the cost alone — it's the cost per lead the site generates.
Making the Right Choice: Ready-Made Theme or Full Code?
The choice depends on your 3-5 year ambition, not only on today's budget. A ready-made theme is enough for a first online presence or a very standard need: the initial cost is low, but licences, plugins and fixes add up, and the site is harder to make stand out. A full-code website costs more upfront (from €3,200 at Agence Zen, depending on scope) and includes strategy, copywriting, design, SEO/GEO and guaranteed performance. Then the technology — Next.js or WordPress with a theme built from scratch — is chosen based on how you will edit your content and the features you need.
Moving From a Ready-Made Theme to a Full-Code Website
If your current site runs on a ready-made theme, there are two paths. Stay on WordPress and replace the theme with one built from scratch for your site: your content and admin can be kept, and only the layouts that depend on the old theme have to be reworked. Or move to Next.js: your content is carried over to the new site and its CMS. Either way, the method is the same: (1) a full audit of the current site (content, URLs, backlinks, features), (2) design of the new site with the improvements identified, (3) content migration with a 301 redirect for every URL that changes, (4) launch and Search Console monitoring.
The most important point: don't lose a single link. Every page of your current site that Google indexes and that receives traffic must redirect to its equivalent on the new site. Without it, you lose rankings — an invisible cost that can take months to recover. The SEO migration is included in Sur-mesure and available as a €690 option with Essentiel and Signature.
Planning Ahead: Why Full Code Ages Better
A site built on a ready-made theme tends to accumulate technical debt: a theme its vendor no longer updates, new theme versions that change the rendering, plugins added one need at a time, content tied to the theme's layouts. At some point, a full redesign can become the only way out. A well-built full-code website, in Next.js as in WordPress, rests on code you own and that is documented: it can evolve step by step — new features, a refreshed design, better performance — without starting over.
FAQ
Is WordPress really free?
The software is free (open source). A real site adds hosting, often a premium theme licence, premium plugins, and maintenance time. At Agence Zen, a full-code WordPress site, with a theme built from scratch, follows the same price grid as a Next.js site, with hosting and maintenance included for 12 months, then €89/month.
Is WordPress good for SEO?
Yes, if it is well built. What holds a WordPress site back is not WordPress itself, but a ready-made theme loaded with unused features or a pile of plugins. With a theme built from scratch, a WordPress site can be as lean and well structured as a Next.js site: at Agence Zen, the guaranteed speed score of 90+ on mobile applies to both.
Can I move from a ready-made theme to a full-code website?
Yes, either to WordPress with a theme built from scratch, keeping the admin you already know, or to Next.js. We carry over your content and deliver a faster site. The SEO migration (URL inventory, page-by-page 301 redirects, Search Console monitoring) is included in Sur-mesure and available as a €690 option with Essentiel and Signature.
Does the price depend on the technology?
No. The Essentiel, Signature and Sur-mesure plans cost the same whether the site is built in Next.js or in WordPress with a theme built from scratch, and the guaranteed speed score of 90+ on mobile applies to both.
What about Wix, Squarespace, or Shopify?
No-code tools like Wix and Squarespace are fine for getting started quickly on a small budget. Their limits: partial control over code and performance, constrained technical SEO and structured data, and a site that is hard to move elsewhere. Shopify is a solid e-commerce platform, which we can connect to a custom site in the Sur-mesure plan. For a business site that has to generate leads, we recommend a full-code website, in Next.js or WordPress.
Can I edit content on a full-code website?
Yes. With WordPress, you edit in the WordPress admin from the Essentiel plan; with Next.js, in a simple editing interface included from the Signature plan and available as a €690 option with Essentiel (together with the blog). Most small business sites need updates quarterly, not daily: the support period and the care plan include 1 hour of changes per month.
What about e-commerce?
We integrate the shop that fits your project: WooCommerce on a full-code WordPress site, Shopify or Stripe with Next.js. The choice depends on the size of your catalogue, your tools and who manages orders.
The best technology is the one that serves your business goals. Don't choose based on popularity — choose based on performance, cost, how you will edit your content, and the experience you want to give your visitors.