prioritize mobile or desktop when designing the website

This question appears in nearly every web project Sinh Vũ has participated in. You often ask because you've heard that "mobile is more important" but see the design team presenting the desktop version first. The straightforward answer is: for most consumer businesses in Vietnam, prioritizing mobile is the correct default choice. However, the final decision must be based on the actual customer demographics of your business, not the average figures for the entire industry.

Two concepts need to be distinguished

Many people confuse responsive design with mobile-first. These are two different things.

• Responsive (multi-device compatible): techniques that allow layouts to automatically resize according to screen dimensions. This is a minimum requirement, not an advantage.
• Mobile-first: a design approach that starts from the smallest screen, around 375 to 390 pixels equivalent to iPhone SE or basic Pixel, then gradually expands to larger screens. This is the opposite of the old method of designing for desktop first and then scaling down.

A website can be responsive without being mobile-first. The mobile version is often just a scaled-down desktop version: small text, hard-to-click buttons, and cut-off content.

Which factor determines the reality?

Before choosing a direction, you need to answer these two questions:

• What is the mobile proportion? Check Google Analytics or data from the hosting platform. If most traffic comes from mobile, the mobile version is the true face of the website.
• What tasks do customers perform? Reading information, viewing product images, and filling out simple order forms can be done well on a phone. Complex data entry, comparing multiple columns, and working on large data sets require a computer screen.

Moreover, since 2019, Google has indexed based on the mobile version of websites (known as mobile-first indexing). This means that if your mobile version lacks content or runs slowly, search rankings will be affected even if the desktop version is perfect.

When to choose which direction

Common errors to avoid

• Beautiful design on desktop then squeezed down to mobile: The result is often too small text, buttons too close together, requiring customers to zoom in to interact. This poor experience is why customers leave the page.
• Reduce content on the mobile version: Some designs hide important content on mobile to create a cleaner layout. Google reads the mobile version, and if content is missing, search rankings will drop.
• Touch area too small or too close: Fingers are not mouse pointers. Buttons and links need to be wide enough for accurate touches without needing to zoom in.
• Ignore mobile network speed: Phones do not always have wifi. Heavy images and unnecessary scripts that slow down page loading will degrade both the experience and ranking.

Mobile-first design is not just about creating a mobile version and calling it a day. It is a discipline that starts from the smallest constraints so that every design decision has a reason, then expands in a controlled manner to larger screens.

Practical experience, Sinh Vũ Studio

The viewpoint of Sinh Vũ

Sinh Vũ approaches with the principle: see the real numbers first, decide later. For projects without data, Sinh Vũ defaults to a mobile-first approach for consumer websites as this is the less risky direction: a good mobile version can easily scale up to desktop, but a beautiful desktop version that scales down poorly must be redone almost from scratch.

For B2B projects or specialized tools, Sinh Vũ asks detailed questions about the actual workflow of end users before prioritizing tasks. There is no one-size-fits-all formula. However, regardless of which device is prioritized, the mobile version must always be functional and content-rich, as Google makes no exceptions.