ecomrestack

battles / Analytics

Amplitude vs FullStory

Amplitude ($1,200/mo/mo, vibe code 3/10) vs FullStory ($850/mo/mo, vibe code 3/10). FullStory is the easier one to rebuild yourself — here is what you lose either way.

Amplitude
KEEP

Analytics

$1,200/mo/mo

Vibe code3/10
Moat6/10
MVP
3-4 weeks
Full replacement
12-18 months
get the build prompt →
FullStory
KEEP

Analytics

$850/mo/mo

Vibe code3/10
Moat5/10
MVP
1 week
Full replacement
12-24 months, due to massive DOM storage scale, real-time query engines, and client-side PII masking.

easier to rebuild

get the build prompt →

price gap / year

$4,200/mo

running both / year

$24,600/mo

our call

Start with FullStory — highest vibe code, weakest moat.

Amplitude

Building a basic event logger and UI takes a few hours, but reproducing Amplitude's query speed across billions of unaggregated events is an infrastructure nightmare. You will sink months into managing ClickHouse clusters, handling session stitching, and tuning DB performance.

you can rebuild

  • Basic funnel drop-off calculation across sequential event steps.
  • Client-side JavaScript event capturing for pageviews and button clicks.
  • Simple user retention charts (Day 1, Day 7, Day 30 retention).
  • User timeline viewing showing event sequences for specific IDs.
  • Basic cohort segmentation based on static event properties.

what you lose

  • Sub-second response times on dynamic, unstructured behavioral cohort queries.
  • Automated cross-device identity resolution and retroactive user merging.
  • Self-serve UI for non-technical product managers, requiring SQL for custom queries.
  • Native sync capabilities with Snowflake, BigQuery, and enterprise CDPs.
  • Enterprise-grade SLAs, SOC2 Type II compliance, and GDPR data erasure automation.

real moats

  • Proprietary distributed columnar database architecture optimized specifically for non-linear behavioral graph queries.
  • Decade of battle-tested SDK performance to prevent blocking client UI execution on slow networks.
  • Deep ecosystem integrations with CDP platforms (Segment, RudderStack) and data warehouses (Snowflake, Databricks).
  • Data governance, taxonomy controls, and automatic anomaly detection tools built for cross-functional teams.

open source escape hatches

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

Questions people ask

Which is easier to rebuild with AI, Amplitude or FullStory?

FullStory. It scores 3/10 on vibe code with a moat of 5/10, so an AI-assisted MVP takes about 1 week and a full replacement about 12-24 months, due to massive DOM storage scale, real-time query engines, and client-side PII masking..

Which one costs less, Amplitude or FullStory?

FullStory at $850/mo/mo for a typical mid-market store. The gap between the two is about $4,200/mo a year.

What do I lose if I replace Amplitude?

Sub-second response times on dynamic, unstructured behavioral cohort queries. Automated cross-device identity resolution and retroactive user merging. Self-serve UI for non-technical product managers, requiring SQL for custom queries.

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

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