They call it "client-side web development", what is it and why is it billed separately?

Think of it like a restaurant: the back-end is the kitchen cooking the food. The front-end (client side) is the table layout, the way the waiter presents the dish, where the napkin holder sits. Everything your customer sees on screen, clicks, scrolls through, or calculates instantly runs on their own computer and requires dedicated code.

Technically speaking, the server side pulls the raw equipment pricing from the database using PHP or Node. The client side then takes that data using HTML, CSS, and JavaScript, processes it right in the user's browser, triggers animations, and handles dynamic DOM manipulation without reloading the page. Since the calculation engine will run in the browser, most of the actual workload really is on the client side.

We had a cargo volume calculator built for our logistics site last year. 1,800 Euro of the 5,000 Euro total budget went to UI and browser-side coding. We thought it was steep at first, but once the quotes started generating instantly on mobile without lag, our conversion rate jumped big time. Done right, it definitely pays for itself.

Will this client-side calculator they're building integrate automatically with your internal accounting or CRM software? Or will it just drop the calculated total into a form and email it to you? If you're paying 1,400 Euro, it's worth clarifying the API integration details.

Correction: I misremembered the figure, it was a bit lower.

Yes, the work is necessary, but agencies breaking quotes down into fancy jargon and slapping 1,500 Euro on each line is a classic tactic to jack up the price. If they just called it "website build," 4,200 Euro might look high, but labeling it "client-side architecture" makes it sound professional and easier to swallow. Definitely ask for a breakdown of estimated hours.

nothing to worry about you're not getting scammed. in Spain separating "entorno cliente" and "entorno servidor" is standard practicce on agency quotes. they itemize it for transparency then and for Madrid the price isn't outrageous at all—it's pretty reasonable.

without client-side development every time a customer added a day to their rental period, the screen would go white and reload; it'd feel like renting kitchen gear from a 2004 internet cafe then that 1,400 Euro is basically the price of your customers' patience so they don't bounce.

The quote looks completely transparent; if there are dynamic components like an interactive calculator, it's totally normal for this line item to account for a third of the cost.

Great work. If acceptance criteria aren't written, when the work is done is open to debate.

When making a decision, first look at what data you have on hand. If you post the result here, it will help others too.

I've been dealing with this for a long time. The system lives on after delivery; maintenance is a separate line item.

The answer varies greatly by industry; there is no one-size-fits-all rule. If you post the result here, it will help others too.

There are three things to check when doing this. When making a decision, first look at what data you have on hand.

The harder it is to reverse a decision, the slower you should make it. Hope this helps.

I'm a small business, let me explain from my side. The biggest time-waster for us was not knowing who had the final say.

We experienced almost the exact same thing last year. Every "we'll look at it later" in a meeting means unbilled work.

Good luck with that.

Absolutely. If I were to add anything: The biggest time-waster for us was not knowing who had the final say.

If it's your first time, start small; scaling comes later. Proven by experience.

This approach has a cost, which isn't discussed. Ask who prepared the quote and who will actually do the work.

If you get three different answers on a topic, the question was asked wrong. Of course, it varies if your situation is different.

I have a question, don't want to go off-topic though. Any unwritten clause becomes a point of disagreement later, as both sides remember it differently.

The real issue isn't the number, but what it's based on. Of course, it varies if your situation is different.

let me share my experience. solutions that work at a small scale collapse when you grow; I learned this late.

the answer varies greatly by industry; there is no one-size-fits-all rule. hope this helps.

I can't fully agree with this. If you don't write this down from the start, it leads to arguments later.

If you post the result here, it will help others too.