Optimizely vs Statsig
Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.
Entry price
Quote on request
Quote onlyFree tier available
Free tierWhat drives the bill
The metric that actually scales your invoice.
Enterprise annual contracts, commonly in the tens of thousands and up. Priced by traffic and modules.
One of the most generous free tiers in developer tooling; paid usage is billed on analytics events, not seats.
Free tier
No free tier.
Generous free tier including unlimited feature flags and a large monthly event allowance.
Open source
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Widely used
Optimizely · since 2010
Widely used
Statsig (Amplitude) · since 2020
Strengths
- The most capable visual editor for non-technical experiment authoring.
- Deep personalisation and audience-targeting features.
- Established statistics with sequential testing, so peeking is handled correctly.
- Statistics engine is genuinely strong — sequential testing and CUPED are not marketing veneer.
- Flags, experiments and analytics in one system removes a whole class of integration work.
- Warehouse-native mode satisfies data-governance requirements.
Limitations
- Expensive, with a suite-oriented sales motion that pushes adjacent products.
- Client-side testing causes flicker and is increasingly blocked by browsers and blockers.
- Heavyweight for teams that only need a handful of experiments.
- Event-based pricing can escalate sharply on high-volume products.
- Broad surface area means a real learning curve.
- Changed hands twice in under a year — OpenAI acqui-hired the founding team in September 2025, and Amplitude took over the product and brand in May 2026, so the roadmap is still settling.
Best for
Large marketing organisations running continuous experimentation on high-traffic sites.
Product teams that want experimentation and analytics to share one source of truth.
All of these integrate with: Segment, Snowflake, Slack.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.