Search Google Flights (via SerpAPI) between two airports.

Args: departure_id: Origin IATA airport code, e.g. "SEA". Multiple origins may be comma-separated, e.g. "SEA,PDX". arrival_id: Destination IATA airport code, e.g. "NRT". outbound_date: Departure date as YYYY-MM-DD. return_date: Return date as YYYY-MM-DD. Required when trip_type is "round_trip"; ignored for "one_way". trip_type: "round_trip" (default) or "one_way". travel_class: Cabin class. adults, children, infants_in_seat, infants_on_lap: Passenger counts. stops: Filter by number of stops. max_price: Maximum total price in currency. currency: ISO 4217 currency code (default USD). max_results: Cap on options returned per bucket (best / other). deep_search: Slower, but matches google.com/travel/flights more precisely.

For a round trip, each option's price is the total round-trip fare and its departure_token can be passed to get_return_flights to see return options.

Search a multi-city Google Flights itinerary (2+ separate legs).

Args: legs: Ordered list of leg objects, each with "departure_id", "arrival_id", and "date" (YYYY-MM-DD). For example: [{"departure_id": "SEA", "arrival_id": "NRT", "date": "2026-10-03"}, {"departure_id": "NRT", "arrival_id": "ICN", "date": "2026-10-10"}, {"departure_id": "ICN", "arrival_id": "SEA", "date": "2026-10-17"}] travel_class, adults, children, infants_in_seat, infants_on_lap, stops, max_price, currency, max_results, deep_search: as in search_flights.

Each option's departure_token can be passed to get_return_flights to advance to the next leg's options.

List the next set of options after selecting a flight.

Pass a departure_token from a round-trip search_flights result (to see return options) or a multi-city search_multi_city result (to advance to the next leg). Each returned option has a booking_token usable with get_booking_options.

List where to book a selected flight and the price at each provider.

Pass a booking_token from a search_flights (one-way) or get_return_flights result.

Start tracking the price of a route over time.

Saves the search as a watch and records its current lowest price. Re-check with check_prices (or the scheduled checker) to log price history and get alerted on drops. Set target_price to be alerted when it falls to/below that amount. label is a friendly name shown in alerts and listings.

List all saved price watches with their most recent recorded price.

Delete a price watch (and its recorded history) by id.

Re-check every price watch now, record the prices, and report any drops or target hits. Uses one SerpAPI search per watch.

Return the recorded price history (timestamp, price) for a watch.