Price History Methodology
We only show price-history claims that are backed by our own observations. This page explains how we observe, what each evidence tier means, and when we can claim "lowest in N days".
Observation Sources
DealZap records price observations from four sources, ranked by trust:
- Affiliate feed — every ingestion run records the offered price as an observation event. Most common source; lower trust because feeds occasionally lag the merchant site.
- Merchant API / scheduled re-verification — periodic checks against the merchant's own URL. Higher trust.
- Controlled extraction — used only where legally acceptable and operationally stable. Currently dormant.
- Manual operator review — for priority deals or disputes. Highest trust per observation.
Evidence Tiers
Every product carries one of four evidence tiers, computed from its observation count and time-spread:
| Tier | Conditions | Claims allowed |
|---|---|---|
| unverified | No observation history | Just the current price. |
| feed_verified | 1 recent observation from a trusted feed | "Recently checked" timestamp. |
| observed_verified | ≥2 observations across time | "Price tracked" + delta vs previous. |
| historical_verified | ≥3 observations spanning ≥7 days | "Lowest in 30 days", "lowest in 90 days", etc. |
The deal-page badge tells you which tier this product is in. We never show a "lowest in N days" claim for a product that isn't historical_verified. Our blog posts honor the same rule — the AI writer is instructed to skip historic-low language for under-tracked deals.
Watchlist Alerts
When you add a product to your watchlist, we re-check the price every 15-60 minutes (configurable per item). Each check produces a fresh observation event, so over time your watched products climb the evidence-tier ladder. You get an alert when the price drops below your threshold.
What "Stale" Means
Every approved deal has a freshness SLA — the maximum time we accept since the last successful verification. Currently 6 hours for Amazon & Flipkart, 12 hours for Myntra, 24 hours for everything else. If a deal misses its SLA and the next re-verification fails, we mark it stale and pull it from public view. We'd rather hide a deal than risk telling you about a price that's no longer there.