# Responsive Web Design > Responsive design at JM Websites: every site we build is designed mobile-first, tested on real devices and optimized for Core Web Vitals. Not a separate mobile version, but one site that behaves correctly everywhere. Source: https://jmwebsites.nl/en/automatisering/responsive-design --- Responsive Web Design | Mobile-first Websites | JM Websites | JM Websites[Skip to content](#main-content)Automation · Responsive Design # A site that holds up on every screen from old iPhones to ultrawide A large share of your visitors come in via mobile, some via tablet, and a growing group on ultrawide displays. Responsive design makes sure your site looks and runs well on every device, not a shrunken desktop version squeezed onto a phone. [Request free design](/en/gratis-ontwerp)[← Back to all automations](/en/automatisering)Mobile-firstdesigned from the smallest screens up60 fpssmooth animations on modern devicesAll sizesfrom 320px to 3440px+01 ## Who is this for? Three typical situations where this automation pays for itself within months. 01 ### Local business with heavy mobile traffic Customers find you via Google Maps or search on phone for contact details. First impression is mobile, and everything (address, call, inquiry) has to be two taps away. 02 ### B2B site with mixed device usage Prospect researches on desktop during work hours, comes back on mobile in the evening. Both experiences have to feel consistent or they drop off. 03 ### Portfolio or agency site Designers check on ultrawide, clients review on mobile, partners maybe on tablet. None of those can have a weak side. 02 ## What you gain ### Mobile-first workflow We design from 320px up. That way the smallest variant gets the most attention, instead of being patched up last. ### Not just scalable, usable Touch targets big enough, forms short enough, scroll behavior smooth. Good responsive means usable, not just technically fitting. ### Fast loading on mobile Images optimized, fonts lazy-loaded, JavaScript only where needed. Mobile speed is an SEO factor and a conversion factor. ### Future-proof CSS CSS Grid and container queries instead of old media-query hacks. Even new screen sizes hold up without recoding. 03 ## How we build it From first call to live in production. Transparent, predictable, no surprises. 01 ### Define breakpoints and key flows Which screen sizes truly matter for your audience? We look at analytics and pick 3-4 breakpoints to explicitly design for. 02 ### Design mobile-first Wireframes and visuals start at 320px. Then we scale up to tablet, laptop and desktop without undoing earlier choices. 03 ### Build and test on real devices Not only Chrome DevTools, but actual iPhones, Androids and tablets. That's where subtle issues surface that simulators miss. 04 ### Performance check Core Web Vitals on mobile must be green. We measure LCP, CLS and INP on 4G simulation and in production, and adjust where needed. Built withTailwind CSSCSS Grid + FlexContainer queriesNext.js Image optimizationReal-device testingWhat does it cost? Responsive design isn't a standalone service: it's the default approach on every site we build. Websites start at €1,000, see the website page for the full scope. Combining with other automations or a website? We often bundle these together, it genuinely saves in practice. [Request a custom quote](/en/gratis-ontwerp)[Or send a message](/en#contact)04 ## Frequently asked questions Isn't responsive design standard by 2026?As a starting point yes, but good responsive is different from technically responsive. Many sites scale but still feel awkward on mobile: buttons too small, long forms, sluggish animations. We test on real devices, not just DevTools.Do you build separate mobile and desktop versions?No. One codebase with adaptive CSS, plus occasional device-specific finetuning. Separate mobile sites backfire: SEO drag, double maintenance, inconsistent UX. Responsive-first has been the standard for years.Does your work run on older iPhones or Androids?Down to a reasonable floor (3-4 year-old devices) yes. Truly old browsers we support gracefully: the site works, possibly without the newest effects. During intake we discuss which portion of your audience we need to cover specifically.How do you measure it's actually fast on mobile?We run Core Web Vitals (LCP, CLS, INP) on real 4G simulation and measure in production via Vercel Analytics. Numbers have to be green, not 'reasonable'. Mobile speed is an SEO factor now, so no compromise there.Does this apply to admin or dashboard pages too?Yes. If we build a CMS or dashboard for you, it matters just as much there. If you want to check how many leads came in from your phone between meetings, it has to just work, no swallowed UX in the back office either. ## Goes well with this [ ### Quote Systems Typing every quote by hand while your prospect is already sitting down with a competitor? A quote system generates the offer automatically based on the inquiry, in your brand, ready to send within the hour. ](/en/automatisering/offerte-systemen)[ ### Reporting Automation Few things eat up time like building and merging the same Excel exports every week or month. Built once properly, it's done, and you see live what you want to see, whenever. ](/en/automatisering/rapportage) ## Want to see how this looks at your business? Request a free design, during the follow-up call we'll also discuss which automation would have the biggest impact at your business. [Request free design](/en/gratis-ontwerp)[Or send a message](/en#contact)