Replace your conversion rate optimization agency.
HI Engine does the work you hire a conversion rate optimization (CRO) agency for, and ships it: it finds what’s costing your Shopify store conversions, sizes each issue in $/month, writes the fix to a draft theme for your approval and tests it against a control.
HI Engine next to an agency.
The same goal, a different deliverable. An agency hands you an audit, a roadmap and a list of things your developer needs to do. HI Engine hands you the fix, live on your store and measured.
Implements the fix
- HI Engine
- Yes, writes and publishes the codeNative theme code, no page builder.
- CRO agency
- Sometimes, development billed extra
- Shopify apps
- No, you make the changes
- In-house team
- Yes, with a developer
Time to first fix
- HI Engine
- One day
- CRO agency
- 2–4 weeks
- Shopify apps
- Quick install, you build the fix
- In-house team
- Days to weeks
Prioritization
- HI Engine
- Every finding priced in $/month
- CRO agency
- Consultant estimate
- Shopify apps
- Data, no dollar estimate
- In-house team
- Manual and slow
Theme safety
- HI Engine
- Draft theme, Theme Check, rollback
- CRO agency
- Manual, depends on the team
- Shopify apps
- The risk is yours
- In-house team
- Your responsibility
Reporting
- HI Engine
- Live GA4 and Shopify data
- CRO agency
- Monthly slide deck
- Shopify apps
- Dashboards you interpret
- In-house team
- Manual reports
Pricing
- HI Engine
- Custom, from $700/mo
- CRO agency
- $3–8k/month retainer
- Shopify apps
- Monthly fee per app
- In-house team
- Salaries and time
| Criteria | HI Engine | CRO agency | Shopify apps | In-house team |
|---|---|---|---|---|
| Implements the fix | Yes, writes and publishes the codeNative theme code, no page builder. | Sometimes, development billed extra | No, you make the changes | Yes, with a developer |
| Time to first fix | One day | 2–4 weeks | Quick install, you build the fix | Days to weeks |
| Prioritization | Every finding priced in $/month | Consultant estimate | Data, no dollar estimate | Manual and slow |
| Theme safety | Draft theme, Theme Check, rollback | Manual, depends on the team | The risk is yours | Your responsibility |
| Reporting | Live GA4 and Shopify data | Monthly slide deck | Dashboards you interpret | Manual reports |
| Pricing | Custom, from $700/mo | $3–8k/month retainer | Monthly fee per app | Salaries and time |
The work you hired an agency for, as one loop.
One loop finds, prices, ships and tests every fix. Built to be safe on a live store.
Find
Reads Shopify and GA4, then explains each conversion leak in plain language.
Size
Estimates each fix’s monthly impact and weighs effort and brand risk.
Ship
Writes the code, runs Theme Check, holds it on a draft theme.
Test
Splits visitors 50/50 and measures each change against a control.
We started inside a Shopify agency.
HI Engine is built on five years of conversion rate optimization work for Shopify stores. At every merchant we saw the same folder: an audit or two, a heatmap report and a slide deck, and most of the recommendations never implemented. So we built the engine that ships them.
More from merchants
Jelmer HendriksDore & Rose “With HI Engine, one person now gets the same CRO results that used to take a team of five.”
KyleFounder at Swoveralls “For us, HI Engine did for CRO what Canva did for design.”
Libie Motchan DuggalFulton “HI Engine feels like magic; the opposite of AI slop. Building and launching CRO tests is so easy, I keep thinking, ‘Wait, it can actually do that?!’ At Fulton, it’s meaningfully impacted our conversion rate, engagement rate, and AOV.”
ElizabethCo-Founder, The Great Fantastic (ex-Brooklinen) “HI Engine takes so much of that work and does it for you. It’s an incredibly impressive tool.”
Questions about replacing an agency
Is HI Engine a CRO agency?
No. HI Engine is software that runs the loop a CRO agency is hired for: it finds what’s costing your store conversions, sizes each issue in $/month, writes the fix into your theme and tests it against a control. Nothing goes live without your approval.
What do I get that an agency doesn’t deliver?
The fix itself. An agency engagement usually ends in an audit, a roadmap and a list of tasks for your developer. HI Engine writes each change into your theme as Liquid, JSON and CSS, ships it to a draft theme you can preview in your own store, and reports on live GA4 and Shopify data instead of a monthly slide deck.
Do I still need a developer?
Not to ship the fixes HI Engine writes. It writes and publishes the code itself: native theme code, no page builder, validated with Shopify Theme Check and held on a draft theme until you approve it. Rollback is one click.
How soon is the first fix live?
In the 14-day free trial, we ship your first 3 fixes in the first month. You pay only after they’re live and you’ve seen the results.
How is HI Engine priced compared with an agency?
Custom pricing after the trial, from $700/month, based on your store size, credit usage and results. The 14-day trial itself is free: pay after it works.
Is it safe to let software change my live store?
Your theme, catalog and orders stay read-only until you ask for a change. Every change publishes to a draft theme first, and nothing goes live without your approval. Shopify Theme Check validates each change, every change is logged, and rollback is one click. Your data stays yours. SOC 2 is on our roadmap.
What does HI Engine need from my store?
Shopify and Google Analytics 4: HI reads your theme, orders, sessions and funnels, read-only until you ask for a change. You don’t need a third-party A/B app: if you already test in Intelligems, HI reads those results; without it, HI runs its own tests.
Who is behind HI Engine?
HI Engine started inside a Shopify agency and is built on five years of conversion rate optimization work for Shopify stores. Its founders are Arttu Hietala, Samuli Ala-Kasari and Valtteri Tuominen.