Comparison · 36 merchant reviews read · Updated October 2026
GemX vs Theme Scientist
Short answer
Pick GemX if you need template tests and url split tests and you want the most proven option (25 reviews).
Pick Theme Scientist if you need theme tests and content tests and you want the lowest starting price ($9.99/month).
 GemX |  Theme Scientist | |
|---|---|---|
| App Store rating | 4.8★ (25) | 4★ (13) |
| Cost at your traffic | $49+/moStarting price. The listing says price rises with revenue but gives no tiers. | $29.99+/moYour traffic is above the listed limits. Tester Pro is the floor, expect a custom quote. |
| How price scales | Starts at $49/month for single-page testing, or from $99/month (up to $699) for full-funnel testing, with the Funnel plan price rising with your monthly store revenue. | Starts at $9.99/month with a 14-day free trial, and the price goes up as your store's monthly order limit increases (50, 250, or 500 orders). |
| Launched | September 23, 2024 | March 5, 2020 |
| App Store listing | App Store listing |
Theme Scientist starts at $9.99 a month, GemX at $49
GemX
- Page Optimize$49/mo
- Funnel Optimize$99/mo
“Starts at $99 and goes up to $699. Pricing scales based on monthly sitewide revenue.”
Theme Scientist
- Tester$9.99/mo
- Tester+$19.99/mo
- Tester Pro$29.99/mo
Only GemX can run template tests
Read from each app's listing. A dot means the listing says it can do it.
| GemX | Theme Scientist | |
|---|---|---|
| Theme tests | ○ | ● |
| Template tests | ● | ○ |
| Content tests | ○ | ● |
| URL split tests | ● | ○ |
| Offer tests | ● | ○ |
| Audience targeting | ● | ○ |
What reviewers complain about
Share of each app's reviews that complain about the topic. Apps under 20 reviews are left out because a single review swings the number.
| GemX | |
|---|---|
| Price | 0% |
| Billing and refunds | 0% |
| Support | 4.3% |
| Bugs | 4.3% |
| Setup | 0% |
| Dashboard | 0% |
| Reporting and stats | 4.3% |
| Flicker | 0% |
| Page speed | 0% |
| Integrations | 0% |
| What you can test | 0% |
| Results | 4.3% |
The most common GemX complaint: support
Tracking is inaccurate even after 24 hours. The app doesn't collect data on orders or visitors at all. I wasted two days testing only to see results that make no sense and don't match reality. Support doesn't exist. The support app itself doesn't even work. No way to get help, no responses, nothing. Stay away from this app.
Theme Scientist replies to 85% of reviews, GemX to 44%
| GemX | Theme Scientist | |
|---|---|---|
| Reviews with a developer reply | 44% | 85% |
| Praise support | 73.9% | 69.2% |
| Complain about support | 4.3% | 7.7% |
Serious problems reviewers reported
Billing disputes, broken stores, misused data and missing features. Each one is a single merchant's account.
Tracking is inaccurate even after 24 hours. The app doesn't collect data on orders or visitors at all. I wasted two days testing only to see results that make no sense and don't match reality. Support doesn't exist. The support app itself doesn't even work. No way to get help, no responses, nothing. Stay away from this app.
Results merchants put a number on
- over $50k a year revenue with Theme Scientist, testing multiple growth ideas. “increase our revenue by over $50k a year”
- double conversion rate with Theme Scientist. “double, yes double our conversion rates in 3 months”
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