battles / Analytics
FullStory vs Optimizely
FullStory ($850/mo/mo, vibe code 3/10) vs Optimizely ($3,500/mo/mo, vibe code 3/10). Optimizely is the easier one to rebuild yourself — here is what you lose either way.
Analytics
$850/mo/mo
- MVP
- 1 week
- Full replacement
- 12-24 months, due to massive DOM storage scale, real-time query engines, and client-side PII masking.
Analytics
$3,500/mo/mo
- MVP
- 1 week
- Full replacement
- 12-18 months, due to the complex sequential statistical engine, WYSIWYG visual editor, and high-throughput edge routing infrastructure.
easier to rebuild
get the build prompt →price gap / year
$31,800/mo
running both / year
$52,200/mo
our call
Start with Optimizely — highest vibe code, weakest moat.
FullStory
Wrapping rrweb into a web app takes a few days, but storing millions of DOM diffs without killing client performance or ballooning cloud database bills requires serious infrastructure engineering. Client-side PII masking, SOC2 compliance, and fast event indexing cannot be prompt-engineered.
you can rebuild
- Client-side DOM event and mutation recording
- Basic session replay video playback
- Console logs and network request capturing
- Simple click and scroll heatmaps
- Basic funnel step tracking
what you lose
- Automated client-side PII and sensitive input field masking before data transmission
- Instant retroactive search over unindexed DOM text and element CSS selectors
- Frustration heuristics like rage clicks, dead clicks, and error clicks
- Enterprise compliance certifications including SOC2 Type II, HIPAA, and GDPR tooling
- High-throughput event ingestion infrastructure optimized for gigabytes of raw DOM diffs
real moats
- Patented client-side DOM capture and event compression engine
- Proprietary retroactive search index over raw DOM mutation streams
- SOC2 Type II, HIPAA, and strict client-side PII masking guarantees
open source escape hatches
- PostHog MIT
- OpenReplay Apache-2.0
- rrweb MIT
Optimizely
Basic A/B split routing is easy to code, but Optimizely's value lies in its sequential statistical engine (which prevents false positives during continuous peeking), WYSIWYG visual DOM editor, edge-side variation delivery, and SOC2 enterprise governance. Rebuilding the visual editor and statistical rigor from scratch is an unnecessary engineering sinkhole.
you can rebuild
- Simple URL-redirect split tests
- Basic client-side JavaScript DOM element swappers
- Simple flag-based feature toggles
- Manual audience segment targeting rules
- Conversion event logging to custom database tables
what you lose
- Stats Engine continuous peeking sequential analysis (mSPRT)
- Marketer-friendly WYSIWYG visual editor with CSS/JS injection
- Zero-flicker edge execution via Cloudflare/Akamai workers
- Multi-armed bandit automated traffic reallocation algorithms
- Enterprise role-based access control, SAML SSO, and audit logs
real moats
- Proprietary sequential statistics model that prevents false positive statistical significance
- Deep organizational lock-in across non-technical marketing and CRO teams
- High-volume, sub-millisecond edge infrastructure integration
open source escape hatches
- GrowthBook MIT
- Flagsmith BSD-3-Clause
- PostHog MIT
Questions people ask
Which is easier to rebuild with AI, FullStory or Optimizely?
Optimizely. It scores 3/10 on vibe code with a moat of 4/10, so an AI-assisted MVP takes about 1 week and a full replacement about 12-18 months, due to the complex sequential statistical engine, WYSIWYG visual editor, and high-throughput edge routing infrastructure..
Which one costs less, FullStory or Optimizely?
FullStory at $850/mo/mo for a typical mid-market store. The gap between the two is about $31,800/mo a year.
What do I lose if I replace FullStory?
Automated client-side PII and sensitive input field masking before data transmission Instant retroactive search over unindexed DOM text and element CSS selectors Frustration heuristics like rage clicks, dead clicks, and error clicks
What do I lose if I replace Optimizely?
Stats Engine continuous peeking sequential analysis (mSPRT) Marketer-friendly WYSIWYG visual editor with CSS/JS injection Zero-flicker edge execution via Cloudflare/Akamai workers
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