The verdict in three sentences
For a deeptech prospecting internationally, a fast mobile site is a sales argument as much as an SEO signal. In 2026, a front-end optimization (AVIF images, lazy loading, edge CDN, JavaScript budget) costs 4,000-12,000 EUR over 3 to 6 weeks, targeting LCP < 2 s. You typically take a page from 3.4 MB to under 900 KB and a Lighthouse score from 62 to 95+.
What bloats a page and how to trim it
Page weight mostly comes from uncompressed images, multiple fonts, tracking JavaScript and third-party scripts. Optimization combines modern image formats (AVIF/WebP), deferred loading, caching close to the user (edge CDN) and discipline on embedded code.
| Lever | Before | After | Gain |
|---|---|---|---|
| Images (format and compression) | 2,100 KB | 380 KB | -82% |
| JavaScript | 720 KB | 240 KB | -67% |
| Web fonts | 260 KB | 90 KB | -65% |
| Third-party scripts | 320 KB | 110 KB | -66% |
| Total page weight | 3,400 KB | 820 KB | -76% |
| Mobile Lighthouse score | 62 | 95 | +33 pts |
How much optimization costs and what it returns
Budget depends on the number of templates to optimize and the state of the existing code. Speed has a direct, measurable impact on conversion. 2026 orders of magnitude.
| Service | Range EUR | Delay | Target |
|---|---|---|---|
| Image optimization + CDN | 4,000 - 6,000 | 3 weeks | LCP < 2.5 s |
| Full front-end optimization | 6,000 - 9,000 | 4-5 weeks | LCP < 2 s, Lighthouse 90+ |
| Performance front rebuild | 9,000 - 12,000 | 5-6 weeks | Lighthouse 95+ |
| Edge CDN (setup) | 800 - 2,000 | 1 week | TTFB < 300 ms |
| Typical conversion impact | +8 to +20% | - | by sector |
Mini case study
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Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Elodie, VP marketing of a deeptech in Amsterdam, starts at a 3.4 MB site and a mobile Lighthouse of 62. She invests 8,500 EUR to reach 820 KB and a score of 95. The site gets 14,000 sessions/month at a 2.2% demo-request rate, i.e. 308 demos. Speed improves mobile conversion by +15%, adding 46 demos/month. At a 12% close rate and a 9,000 EUR average annual contract, that's 46 x 12% x 9,000 EUR = 49,680 EUR of added pipeline per month. The investment repays in the first week.
FAQ
Do I need a full rebuild to gain speed? Rarely. Most gains come from image optimization and CDN, without touching the design. A front rebuild is only justified if the code is old or too heavy.
AVIF or WebP in 2026? AVIF compresses better (lighter files at equal quality) and is now widely supported. AVIF is often served with a WebP fallback for the rare old browsers.
Is an edge CDN useful for international prospects? Yes, decisively so: serving content from a node near the user cuts TTFB by hundreds of milliseconds internationally.
Does speed really change conversion? Yes, the impact is measurable: depending on the sector, shaving one or two seconds of LCP improves conversion by 8 to 20%, especially on mobile.
How long does optimization last? Without discipline, a site re-bloats with new pages and scripts. A performance budget and monitoring prevent gradual degradation.
Let's scope your project. Send us your URL, current page weight and Lighthouse score, and we'll cost the optimization with a speed target. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
