# Shopify speed optimization & CRO.

- URL: https://sevsolutions.com/services/performance-cro

Speed optimization and conversion rate optimization (CRO) for Shopify and Shopify Plus merchants: Core Web Vitals, Lighthouse 90+, and checkout A/B tests. We measure before we ship, instrument everything, and only call a change a win when the data agrees.

- Target: LCP < 1.8s
- Target: INP < 200ms
- Target: CLS < 0.05
- Avg. lift: +184%

## Speed wins. Experiments prove it.

- **LCP improvement** (−54%): 3.1s → 1.4s
- **INP improvement** (−62%): 360ms → 140ms
- **CLS score** (0.02): Below 0.05 target
- **PageSpeed (mobile)** (98): ↑ from 62
- **Conversion rate** (+184%): Avg. client lift
- **AOV lift** (+22%): Bundle + upsell
- **JS bundle size** (−41%): 412kb → 243kb
- **Checkout drop-off** (−18%): Step 2 → 3 friction

## Ninety days, fixed scope.

How our speed engagements run, against a written performance budget both sides sign. Most stores reach 95+ mobile Lighthouse within 60 days; the third month makes the gains last.

1. **Audit & baseline**: Weeks 1–2. We pull your real-user Core Web Vitals, run Lighthouse on your top templates, list every app and set up real-user monitoring. You get a written report of the wins, in order.
2. **Images & fonts**: Weeks 3–6. Right-sized images, subset fonts and trimmed templates. This is where most of the score moves: typically 20–30 Lighthouse points.
3. **Scripts & apps**: Weeks 7–9. App scripts load only where and when they're needed, stale tags go, theme JavaScript gets trimmed: smaller score gains, a much bigger INP improvement.
4. **Make it last**: Weeks 10–12. Critical CSS, the last fixes, a Lighthouse check in CI that catches regressions, and a runbook your team keeps.

## Questions we hear

### What do you measure?

Core Web Vitals from real users (Chrome's CrUX data, which Google ranks on), Lighthouse in CI, and real-user monitoring that shows a change within hours. We target LCP under 1.8 s, INP under 200 ms and CLS under 0.05. When Lighthouse and CrUX disagree, CrUX wins.

### Which checkout changes are worth making?

First check what Shopify's checkout already does: it's one page by default, express buttons such as Shop Pay sit at the start, and address suggestions are on by default where Shopify offers them. Then test one change at a time: on the Grow plan or higher, Shopify's Rollouts can run a change as an experiment against your current checkout.

### How do you run A/B tests?

Each test is planned before it starts: a hypothesis, a sample size and an end date. Tests run at least 14 days, nobody calls a winner early, and results are split by device, because a change can win on mobile and lose on desktop.

### How soon will we see results?

Most of the speed gain lands in weeks 3–6. On conversion, we check your checkout settings first, and the tests specific to your store run until day 90.

### Will you remove our apps?

Only with your sign-off. We sort every app by when it has to load: checkout, cart and search load first; reviews and recommendations wait until they scroll into view; pop-ups wait until the page is idle. Apps nobody has used in 90 days come out, with your approval.

### What do we keep when the engagement ends?

A runbook: how to run the performance audit (we hand over the CI workflow), how to check a new app against the budget, and what to do when field data shows a regression. The CRO program comes with its own runbook, so your team can run it every quarter without us.