IT & SaaS · Web Development Case Study

9 Seconds to 1.4 Seconds — a Performance Rebuild

FlowStack's marketing site was actively losing signups before a single word was read — a 9-second load time on a bloated legacy stack. Here's how a Next.js rebuild cut load time by 84% and bounce rate by 46%.

★★★★★5.0/5 8-week rebuild Next.js performance build
9s → 1.4s
homepage load time
−46%
lower bounce rate
+61%
more trial signups, same traffic
IT & SaaS
Next.js
Performance Engineering
Client

FlowStack

B2B project-management SaaS platform

Starting point

9s load time, high bounce rate

Legacy stack, unoptimized images, no caching strategy

Engagement window

8-week rebuild

Fixed price, fixed timeline

Services

Web Development

Next.js rebuild, Core Web Vitals optimization

The challenge

Losing Signups Before the Page Even Loaded

FlowStack's marketing site ran on an aging legacy stack that had accumulated years of unoptimized images, unused scripts and no real caching strategy. Homepage load time on real mobile connections stretched past 9 seconds — long enough that most visitors never saw the pricing page at all. Paid traffic from LinkedIn and Google was landing on a page that actively pushed people away before the product had a chance to make its case, and every marketing campaign was quietly fighting the website itself.

9s load time on real mobile connections,
before the rebuild began
01 — What we did

The Rebuild, Start to Launch

1Week 1

Performance Audit

Profiled every render-blocking script, oversized image and third-party embed dragging down load time.

2Week 2–3

Next.js Rebuild

Rebuilt the marketing site on Next.js with static generation for content pages and image optimization built in by default.

3Week 3–5

Core Web Vitals Pass

Eliminated layout shift, deferred non-critical scripts, and tuned caching until every page hit green Core Web Vitals.

4Week 5–6

Pricing & Signup Flow Rework

Rebuilt the pricing and signup pages to load instantly and get out of the way of the conversion action.

5Week 6–7

QA Across Devices & Networks

Tested load time and interactivity on real 4G connections, not just fiber, before sign-off.

6Week 8

Launch & Monitoring

Zero-downtime launch with real-user monitoring in place to catch any performance regression immediately.

i

Speed is a growth lever, not a vanity metric. The moment load time dropped under 2 seconds, the same LinkedIn and Google campaigns that had plateaued started converting meaningfully more trial signups.

02 — Results

From a Slow Leak to a Fast Funnel

Load Time
9s → 1.4s
homepage load time

An 84% reduction in load time, measured on real mobile 4G connections, not just fiber.

Bounce Rate
−46%
lower bounce rate

Visitors now actually stay long enough to see the product's value proposition.

Trial Signups
+61%
more signups, same traffic

The exact same marketing campaigns converted significantly more once the site stopped fighting them.

Site Performance
Post-launch
Load time
1.4s
Bounce rate
−46%
Trial signups
+61%
Core Web Vitals
Before → After
MetricResult
Largest Contentful Paint7.8s 1.1s
Cumulative Layout Shift0.34 0.02
Time to Interactive9.6s 1.6s
PageSpeed score (mobile)31 96
03 — In their words

What the CTO Says

★★★★★

"Most agencies vanish post-launch. ZielDigital set up training, handed us full ownership of the code, and their support plan means fixes happen same-day."

AG
Aakash Gupta
CTO, FlowStack
Methodology

Load time and Core Web Vitals are measured via PageSpeed Insights and real-user monitoring on production traffic. Bounce rate and trial-signup figures come from GA4, compared across equivalent traffic periods before and after launch. Timeframe and starting baseline stated above, as with every case study we publish.

Next Step

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