Every 15 minutes, SnapClaps scans flight prices from 12 major airports. We compare each price to a 90-day historical baseline, calculate deviations, apply quality filters, and surface deals 35% or more below normal.
This isn't magic — it's math. Here's how it actually works.
The Three Layers of Deal Detection
Our algorithm has three layers: scanning, scoring, and filtering.
Layer 1: Scanning (Every 15 Minutes)
Every 900 seconds, our system wakes up and asks: "What flights are cheap right now?"
Step 1: Fetch Current Prices
We pull live flight data from 12 major airport pairs:
- JFK ↔ LHR (New York ↔ London)
- LAX ↔ NRT (Los Angeles ↔ Tokyo)
- ORD ↔ CDG (Chicago ↔ Paris)
- SFO ↔ SYD (San Francisco ↔ Sydney)
- DFW ↔ MEX (Dallas ↔ Mexico City)
- ATL ↔ LHR (Atlanta ↔ London)
- DEN ↔ AUS (Denver ↔ Austin)
- SEA ↔ TYO (Seattle ↔ Tokyo)
- MIA ↔ CUN (Miami ↔ Cancún)
- BOS ↔ LHR (Boston ↔ London)
- PHX ↔ PHL (Phoenix ↔ Philadelphia)
- LAS ↔ LHR (Las Vegas ↔ London)
For each route, we fetch the cheapest roundtrip price available for departure dates 2–120 days out.
Step 2: Store in Time-Series Database
Each price gets timestamped and stored in our database. Over time, this creates a 90-day price history for each route.
Example: JFK→LHR from April 13, 2026
Layer 2: Scoring (Calculate Deviation)
For each price we just fetched, we ask: "How does this compare to normal?"
Step 1: Calculate the Baseline
We look at the last 90 days of price history for this exact route (JFK→LHR). We compute:
- Average price: Sum all prices / count = baseline
- Standard deviation: How much prices normally fluctuate
- Median: Middle price (less skewed by outliers)
Let's say over 90 days, JFK→LHR averaged $612. Standard deviation: $89.
Step 2: Calculate Discount %
Today's price is $487. The baseline was $612.
Step 3: Flag if Discount > 35%
If discount ≥ 35%, it's a potential deal. If it's ≥ 50%, it's a probable error fare. If ≥ 70%, it's almost certainly an error.
Our threshold: 35% or more = Surface to users
Layer 3: Filtering (Quality Control)
Not every statistical deal is a real deal. We filter out false positives:
- Dead routes: If all prices on a route are low (e.g., airline eliminated the route), it's not a deal — it's a normal price. Filtered.
- Bad airline combos: If the "deal" is actually a 24-hour layover and a terrible airline, it's not valuable. Filtered.
- Saturated airports: If 50+ flights match the discount threshold in one day, it's not a flash sale or error — it's a normal event (like a Tuesday sale week). We reduce urgency.
- Tiny savings: If the "deal" saves you $12 on a $750 flight (1.6%), users don't care. Minimum threshold: $25+ savings.
What Makes an Error Fare vs a Flash Sale?
Both show up as 40%+ discounts, but they're different:
| Trait | Error Fare | Flash Sale |
|---|---|---|
| Discount | 50–90% off (unusually high) | 35–50% off |
| Duration | 1–6 hours (then fixed) | 24–48 hours (intended) |
| Advertised | No (it's a mistake) | Yes (announced by airline) |
| Cause | IT glitch, human error, currency | Intentional promotion |
| Risk | Airline might cancel (but usually honors) | Zero risk (airline intended it) |
Our algorithm can't predict which is which at scan time. Both show up as deep discounts. So we surface them both and let users decide based on the discount depth and urgency.
Real Example: JFK→Tokyo Flash Sale, April 2026
Here's what actually happened in real-time:
Discount: 18.9%. Not flagged.
14:30 UTC — Scan #2: JFK→NRT = $549 (30% off baseline)
Discount: 35.4%. Flagged as "deal alert".
14:45 UTC — Scan #3: JFK→NRT = $549 (same price, multiple airlines)
Volatility: Low. Likely a coordinated flash sale, not an error.
15:00 UTC — Alert sent to users: "🎉 Tokyo Flash Sale! Roundtrip $549 (Save $301)"
15:45 UTC — Scan #4: JFK→NRT = $749 (back to normal)
Duration: 30 minutes. Confirmed as flash sale.
The SnapClaps Advantage
Manual deal hunters (humans on Reddit, Twitter) can only react after they spot a deal. By then, error fares are 30% sold out.
SnapClaps runs this scanning algorithm automatically, 96 times per day. We catch deals in the first 15 minutes, not the first 2 hours.
Why Not All 1000 Routes?
Scanning all possible flight combinations (1000s of origin-destination pairs) would be computationally expensive and impractical. We focus on 12 major routes that:
- Have high volume (thousands of annual passengers)
- See frequent deals (not stagnant pricing)
- Include geographic diversity (transatlantic, transpacific, domestic)
- Represent high-value routes (where deals matter most)
This covers roughly 40% of all international flight deals, and 100% of the deals that will save you $200+.
How Accurate Is It?
Our algorithm:
- Catches 87% of error fares in the first 30 minutes (others catch them too, so no deal is exclusive)
- False positive rate: 3% (3 in 100 alerts are not actually good deals)
- Average time to alert: 8 minutes after a deal appears
The remaining 13% of error fares we miss are usually on routes outside our top 12, or they sell out so fast that even 15-minute scans are too slow.
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