GTFS vs Custom Feeds: What’s the Best Standard for Your City’s Transit Data?

Most cities eventually reach this point.

Someone says, “We need GTFS.” Someone else says, “We already have our own data format.” IT asks about integration. Operations asks what changes. And leadership wants to know which option makes more sense long term.

The discussion usually becomes technical very quickly. But the real issue isn’t technical. It’s practical. What kind of data structure will actually support your city’s transit system — not just today, but as it grows?

What GTFS Is — and Why It Became the Default

GTFS is essentially a shared language for transit schedules. It tells digital systems how to read your routes, stops, trips, calendars, and fare information.

Because it’s widely adopted, most journey planners and mapping platforms already understand it. That’s its biggest strength. If you publish a proper GTFS feed, your services can appear correctly in third-party apps without custom development. For cities trying to improve transparency or make their network more visible, that’s a major advantage.

But it’s important to remember something: GTFS was created primarily for publishing schedule data. It wasn’t designed to run your operations. It wasn’t built to handle every internal performance requirement or contract model.

That distinction matters more than most cities initially realise.

Where GTFS Works Very Well

GTFS works well when your goal is clarity and standardisation.

If your system runs fixed routes with defined stops and stable timetables, GTFS can handle that cleanly. It makes it easier to:

• publish schedules
• integrate with journey planners
• support multimodal planning
• maintain consistent public-facing information

It reduces friction when working with technology vendors because you’re speaking a format they already recognise.

For many authorities, that alone justifies implementing GTFS. But the moment you step into deeper operational questions, you start seeing the limits.

When Custom Feeds Start Becoming Necessary

Operational reality is rarely as simple as a schedule file. Cities often need to track fleet assignments, depot logic, performance compliance, service-level agreements, trip completion accuracy, and various reporting formats that GTFS does not natively capture.

You can extend GTFS to some degree, but at a certain point, custom data layers become necessary.

For example:

• A control center may require live performance indicators.
• A contract may require specific compliance fields.
• A regulator may require reporting structures that GTFS doesn’t define.

That’s where custom feeds come in. They give flexibility. They reflect how your system actually operates. The downside? They don’t integrate as easily with external platforms. Every integration becomes a discussion.

This is why most mature transit systems don’t treat it as a binary choice. They use GTFS as the public-facing standard and maintain structured custom feeds for internal intelligence.

The Real Challenge Isn’t Format — It’s Maintenance

There’s another truth that doesn’t get discussed enough. Choosing GTFS or custom feeds is one thing. Maintaining them accurately is something else entirely. Routes change. Timetables shift. Temporary diversions appear. Stops are relocated. If updates are manual or disconnected from planning systems, data goes out of date quickly.

And once passengers notice inconsistencies between apps and reality, trust drops fast.

The cities that succeed with transit data are not the ones that simply adopt a standard. They are the ones that connect their scheduling and operational systems directly to their published feeds.

That’s where systems like RouteSync from Arena Softwares make a difference. Instead of treating GTFS as a separate export task, the data flows from the core planning logic itself. That reduces errors and keeps both standard and custom feeds aligned.

So What’s the Right Choice?

If your goal is interoperability and visibility, GTFS is not optional anymore. It’s become the baseline expectation. If your goal includes deeper operational insight, contract monitoring, or advanced analytics, you will likely need structured custom feeds as well.

The mistake many cities make is assuming one replaces the other.

In practice, the strongest data strategies treat GTFS as the public standard and custom feeds as the operational layer underneath.

Closure

Transit data isn’t just a technical format decision anymore. It shapes how your city integrates with mobility platforms, how accurately services are represented, and how confidently operations can be monitored. GTFS gives you structure and compatibility. Custom feeds give you flexibility and control. The real value comes from designing a system where both can coexist without manual duplication.

With platforms like RouteSync, powered by Arena Softwares, cities can manage that balance — publishing clean GTFS feeds while maintaining the operational intelligence needed to run a modern transit system.