ChannelSpy
YouTube competitor intelligence — for people who hate guessing
Next.js 15 · TypeScript · YouTube Data API v3 · Recharts · GA4 · Vercel
the problem
YouTube Studio is well-designed for your own analytics and completely silent about everyone else's. That's deliberate — showing competitor data would push creators into pure imitation loops. The side effect: agencies, independent creators, and marketers pricing sponsorships had no native tool. They were screenshotting Social Blade.
the approach
A full-stack SaaS dashboard that accepts any YouTube channel URL and returns a complete performance report in under 15 seconds. The backend calls the YouTube Data API v3, applies median-based scoring with IQR outlier detection to handle viral outliers, and returns structured JSON. The frontend renders interactive Recharts visualisations and exports to CSV.
key decisions
↳ Server-side API calls only
API keys never touch the client. All YouTube Data API v3 calls happen in Next.js route handlers. Not clever engineering — just not leaking credentials.
↳ Median + IQR scoring, not mean
One viral video can make a dead channel look healthy if you average views. Median-based scoring with IQR outlier detection means the benchmark reflects typical performance, not lucky performance.
↳ 11-event GA4 instrumentation
Tracking: URL submitted, report generated, chart interacted, CSV exported, and 7 others. 'Users visited' is vanity. Knowing 60% of users export CSV tells you what they actually value.
by the numbers
Report generation time
~15 seconds
GA4 funnel events
11 events
Scoring method
Median + IQR outlier detection
what i actually learned
The most interesting products don't live where the obvious problems are. They live in the gaps left by someone else's deliberate strategic choice. YouTube not showing competitor stats isn't an oversight — it's a moat. Understanding why a feature doesn't exist is more useful than copying one that does.
11-event GA4 funnel · IQR outlier scoring · ~15s to full report