Why we built Tally
Flightlines shows pilots the traffic around them. For that we need what ADS-B receivers hear, from as much of the world as we can reach, live. Until October 2026 we got it the way most projects do: from adsb.lol, an open aggregator that collects what volunteers’ receivers hear and serves it back out.
In October we found its raw stream off for every client, from our own feeder’s address and from addresses that have never fed it. Its query service, which we fell back on, was failing about one request in three. Nobody had done anything wrong. It is a hobby project run by volunteers, and its maintainer says plainly that it comes with no guarantee of availability. That is fair. It is also the problem.
Every open receiver network today is one operator’s servers holding one operator’s list of feeders. When that operator’s stream stops, every client stops with it, and the feeders, who own the antennas, have no way to send their data anywhere else without reconfiguring each box by hand.
A network instead of a service
Tally turns that around. Your receiver signs what it hears and publishes it, once, to a few relays that anyone may run. Relays check each signature and pass every batch on unchanged: they can drop data, but they cannot alter it or invent it. A receiver’s identity is a key it makes for itself, with no account behind it, so no relay operator can take it away. And if a relay goes quiet, your feeder is already publishing to others.
We run relays and read the data like anyone else. Our receivers are feeder number one and Flightlines is client number one, and we hold ourselves to the rule we recommend: if you depend on the data, read it through a relay you run.
What a feeder gets
- Your receptions reach every client at once, through relays you choose, under your own key.
- A page for your station, showing what the network heard from it.
- A feeder that takes no orders: no remote configuration, no self-update, no kill switch, no listening port.
- Data that stays open. You give it under CC0, and what relays publish is under the ODbL, so nobody can take it private.
- It runs beside your existing feeds and changes none of them.
Where it stands
The protocol, the feeder and the relay are built and tested end to end, and our own receivers publish through Tally today. Before anyone else can join, there has to be a public relay with a public address, seeds run by more than one operator, and published release builds. This site shows live data the day the public relay starts.
The code is open, under MIT or Apache-2.0. If you run a receiver, we would like you to try it. If you run servers, we would like you to run a relay.
Install the feeder