How we know: Sources are listed at the end. Descriptions of other services come from their own help pages; descriptions of Wildly come from how the product works today. No fare statistics in this post are Wildly measurements.
A flight price alert is a standing instruction: "check this route on these dates on a schedule, and tell me when the price does X." Every alert service is a variation on those three parts, and understanding them is what separates alerts that save money from alerts that fill an inbox.
Part 1: what gets checked
An alert is tied to a route (origin and destination airports), a date scope (exact dates, a flexible window, or "any dates" in a period), and usually a cabin and stop preference. The service runs a search on that scope and records the lowest fare it finds.
Two things follow from this. First, "lowest fare" depends on what the service can see: some search a single booking channel, some a metasearch feed, some airline sites directly. The same route can show slightly different lowest fares on different services on the same morning. Second, narrower scope means fewer triggers: an alert on one exact date pair fires less often than one that tolerates a few days either side.
Part 2: how often it checks
- Google Flights tracks the route or specific flights you choose and emails you when prices change significantly; on "Any dates" tracking it also sends a periodic email with the best available prices (Google Flights Help).
- KAYAK sends most alerts once a day, bundled into a single early-morning email or push notification, and offers real-time alerts that fire on a significant change, typically about 10% up or down (KAYAK Help).
- Wildly checks each tracked route at least once a day (more often on paid plans) and notifies you by email, and by text if you have verified a phone number.
A daily check is enough for most fare movements, which tend to persist for days. Flash sales and genuine mistake fares can come and go within hours, and no consumer alert service guarantees catching those.
Part 3: what triggers the notification
This is where services differ most.
- Change-based alerts (Google, KAYAK's default) tell you when the price moved, up or down. Useful for building a feel for a route, noisy if you only care about buying.
- Threshold alerts (Wildly) tell you only when the fare falls to or below a target price you set. Quieter, and the notification means "you can book now at a price you already decided was good."
- Prediction-based nudges (Google's price insights, which label a fare low, typical or high versus past prices for the route, and its "cheapest time to book" hint) add a judgement about timing (Google blog). Treat them as one input; they are averages, not promises about your flight.
Setting a target that fires
With a threshold alert the whole outcome depends on the number you choose. Anchor it to today's fare for your dates (from the route page, for example JFK to Paris, LAX to Tokyo or Chicago to London), set a realistic target you would book at, and a second stretch target for the rare drop. Our guide to setting the right price alert target walks through it.
When an alert is the right tool
- Your trip is weeks or months away, so there is time for the fare to move.
- Your dates or airports have some flexibility.
- You would rather decide the price once than check every day.
When to skip the alert and book
- Departure is within two or three weeks and the fare is acceptable.
- It is a peak date (holidays, school breaks, a major event) where fares rarely fall.
- The fare is already at the low end of the route's current range.
Setting up a Wildly alert
- Pick origin and destination and your dates (turn on flexible dates if you can move by a day or two).
- Enter your target price.
- Choose email, text, or both.
That is it. Create a price alert and we check the route every day; when the fare drops below your target you get a message with the price and a link to book with the airline or agency.
FAQ
Do price alerts book the ticket for me? No. Every mainstream alert service, including Wildly, notifies you; you book directly with the airline or an agency.
Why did the price change between the alert and my search? Fares update continuously and cheap seats are limited. If a fare is gone within a few hours, the fare bucket sold out or the airline repriced.
Should I use more than one service? It does not hurt. Different services see slightly different inventory and use different triggers.