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Duffel

iPhone and Mac

Duffel.

Drive or fly. Know before you go.

Line up drive time and fuel against a rough flight estimate. Then get a recommendation based on cost, time, or a balanced call.

Coming to the App Store View on GitHub

How it works

Everything in one trip.

No spreadsheets. Just the inputs you already think about when you decide whether to drive or fly.

  • 01

    Where and when

    Set origin, destination, and travel date. Duffel uses that context for both road and air estimates: one itinerary, two ways to get there.

  • 02

    Road trip math

    Drive duration and fuel cost respect your MPG, airport buffer, and how you like long days behind the wheel. Fuel uses real U.S. retail gasoline averages from the EIA.

  • 03

    Flying estimate

    Flight-side numbers come from an offline estimation algorithm, built for a fair comparison, not live shopping. When you are ready to book, Duffel deeplinks to Google Flights with your trip filled in.

  • 04

    Your priority

    Bias the summary toward saving money, saving time, or stay neutral, so the recommendation reads like how you actually choose trips.

The app

Take a closer look.

Screens from the real app. Trip inputs, comparison cards, the recommendation, and settings.

Duffel home screen with hero headline, weather, map illustration, and trip fields for Indianapolis to Pittsburgh.
Home
Road trip math card with MPG, gas price, people in car, airport buffer, and Compare trips button.
Road trip math
Your comparison screen with drive and fly cards showing time, cost, and actions for Maps and Google Flights.
Drive vs. fly
Drive comparison card with expanded cost breakdown and Start route in Maps button.
Drive costs
Fly card with ballpark time breakdown and Open Google Flights button.
Flight estimate
Map of the driving route and Our 2 Cents cards with final Drive recommendation.
Map and pick
Settings with color mode, sky gradient, drive preferences, and tip jar.
Settings

Coming to the App Store.

Built with Swift and SwiftUI for iPhone and Mac. Until the public listing is live, the GitHub repo is the best place to follow along.

View on GitHub

Privacy policy

Last updated: April 2, 2026

This policy describes how the Duffel app (“the app”), developed by Karteikay Dhuper, handles information. The app is designed to run primarily on your device; it does not require you to create an account in the app.

Information the app may use

  • Locations you enter. Trip origin and destination are used with Apple’s MapKit and related services to geocode places, compute driving directions and distances, and build comparison context.
  • Approximate device location (optional). If you allow it, the app may use your current location once to suggest a starting label for “From” and/or to fetch nearby weather for display on the home screen. You can deny location access and still type locations manually.
  • Preferences you set. Values such as MPG, gas price, airport buffer, drive preferences, and trip priority may be stored locally on your device (e.g. UserDefaults) so the app remembers your choices between launches.

Network and third parties

  • Apple. MapKit and system location services are subject to Apple’s privacy policy.
  • Weather data. The app may request current conditions from a public weather API (e.g. Open-Meteo) using coordinates derived from your location or your trip: only what’s needed for that request.
  • Optional EIA data. If configured, the app may request a U.S. average gas price from the U.S. Energy Information Administration (EIA). An API key, if present, is stored in your project configuration, not on a Dhuper-operated server.

The app does not sell your personal information. Duffel is not intended to host a social network or advertising profile on behalf of the developer based on app usage.

Analytics and ads

If analytics or advertising are added in a future version, this policy will be updated and, where required, additional consent or App Store disclosures will apply.

Children

The app is not directed at children under 13. If you believe we have inadvertently collected a child’s data, please contact us and we will take appropriate steps.

Changes

This policy may be updated when the app changes. The “Last updated” date at the top will reflect the latest revision.

Contact

Questions about this policy or Duffel: use the contact options on kartydhpr.com (for example LinkedIn or email when listed).