Frontend vs backend: what is the difference, and what does each cost?

The owner of a coffee webshop gets an email from her developer: customers can add items to the cart, but orders are not reaching e-conomic, and the problem is in the backend. She nods and replies that they should look into it. But what does that actually mean, and why does the fix cost more than the new homepage she had made last month? Those are the two questions this guide answers, without you needing to code.

What is the difference between frontend and backend?

Think of a physical shop. The frontend is the shop floor: the shelves, signs, price tags and till that the customer sees and uses. The backend is the stockroom, the bookkeeping and the supplier agreements behind it: how many bags of coffee are left, what the price is for a business customer, and how the money ends up in the account. The customer never sees the stockroom, but if it fails, there are empty shelves and wrong prices in the shop.

What happens in frontend and backend when a customer buys from a webshop?

The best way to understand the difference is to follow one order all the way through. Here is the coffee webshop, step by step:

Notice the split. The frontend handles the experience at all five steps, while the backend does the heavy lifting in the last three. That is why the coffee owner’s problem was in the backend: customers could shop, but the connection to e-conomic failed after the payment had gone through. To learn more about how systems talk to each other, read what an API is.

What does a frontend developer do?

A frontend developer turns the design into code that runs in the browser. The job is to make what the designer drew fast, stable and usable for everyone. Typical tasks:

• Build pages and components that work on phone, tablet and desktop.
• Make pages load quickly and meet Core Web Vitals.
• Make the product accessible with keyboard, screen reader and sufficient contrast.
• Handle forms, validation, error messages and empty states.
• Fetch data from the backend and display it, even on a slow connection.

Speed is a frontend responsibility with a direct effect on sales and on Google. We have collected the thresholds and the most important fixes in website speed and Core Web Vitals.

What does a backend developer do?

A backend developer builds the engine room the frontend fetches data from. The work is invisible to customers, yet this is where the business rules live. Typical tasks:

• Design the database so customers, products and orders fit together correctly.
• Build the APIs used by the website, app and admin panel.
• Integrate with payments, accounting, shipping and login, such as MobilePay, e-conomic, PostNord and MitID.
• Secure logins, permissions and personal data under GDPR.
• Handle backups, logging and monitoring, so errors are spotted before customers notice.

What do frontend and backend development cost?

The hourly rate is largely the same. A senior web developer in Denmark typically charges DKK 800–1,400 an hour, and an agency DKK 1,100–1,300, whether the hours go to frontend or backend. The difference lies in how many hours each part needs, and that depends on what the product must do.

Worked example: coffee on subscription

The coffee webshop wants to offer a subscription, so customers get a bag every fortnight. On the frontend, a page is needed where customers choose coffee and interval, plus a page under My account where the subscription can be paused. That is about 20 hours. On the backend, recurring payments, automatic order creation, handling of declined cards and transfer to e-conomic need to be built. That is about 40 hours. At DKK 800–1,400 an hour, the frontend part costs DKK 16,000–28,000 and the backend part DKK 32,000–56,000, a total of DKK 48,000–84,000. The feature looks small to the customer, yet two thirds of the work is invisible.

Standard platform or custom backend?

On a platform like Shopify you rent the backend as part of the subscription, and your spending goes mostly to theme, frontend and apps. It is cheap to start and suits most standard webshops, which typically cost DKK 10,000–80,000 to set up. When the business needs customer-specific prices, special subscription rules or tight ERP integration, a custom backend becomes relevant, and then the price is often well above DKK 100,000. We compare the options in Shopify vs WooCommerce vs custom and in what a webshop costs.

What does it cost to run frontend and backend after launch?

The build price is only the first part. The frontend must keep up with new browser versions, and packages and frameworks need updating so security holes are closed. The backend needs hosting, a database, backups, monitoring and maintenance of integrations every time e-conomic, MobilePay or PostNord changes something in their API. A common rule of thumb is 15–20 % of the build cost per year for maintenance. For the subscription feature above, that means DKK 7,200–16,800 a year. What we see in practice is that integrations need the most attention, because they change outside your control. Make sure failed transfers are logged and retried automatically, so a brief outage at a partner does not leave you with missing invoices.

Is the problem in frontend or backend? A quick guide

What does headless mean for frontend and backend?

In a traditional solution like WordPress, frontend and backend are tightly bound in one system. In a headless solution they are separated: content and data live in a backend or CMS, and the frontend is a separate application, built in Next.js for example, that fetches data via an API. The advantage is design freedom, better speed and the option to use the same backend for website, app and in-store screens. The price is that there are two parts to build and run. We cover when it pays off in headless CMS explained.

Should you hire a frontend developer, a backend developer or both?

For most smaller companies the answer is a developer or team that covers both. A full-stack developer can build a feature from screen to database without hand-offs. Specialists make sense in larger teams, or when part of the product is especially demanding. Whoever you choose, you can use these questions to check that both halves are covered:

1. Who builds the interface, and who builds the database and integrations?
2. How do you test that pages work on mobile and are accessible?
3. What happens to an order if the accounting system is down for an hour?
4. Where does the backend run, and who monitors it?
5. Can the same backend be used if we later want an app?
6. How is the API documented so another developer can take over?

At Ceptiv we build frontend and backend in the same team and the same language, TypeScript, and we have more than 40 pre-built integrations including e-conomic, Dinero, MobilePay, PostNord, Penneo and Stripe. That means fewer invisible backend hours, because we do not start from zero each time. If you want a number for your product, describe it here and you will have a fixed price within 24 hours.