Invalid JSON in Firehose (duplicate key "altChange")


For quite a while now we’ve been receiving invalid JSON on the firehose for the positional events (see below). There is a duplicate key of “altChanged”. This is causing our application to fail to process these events. There is no code change on our side that can be done as this invalidates the JSON specification. This happens about 20 time a minute and is constant. We are specifying version 6 when connecting to the stream.

“pitr”: “1477062571”,
“type”: “position”,
“ident”: “ALK868”,
“alt”: “2500”,
altChange”: “-2099”,
“clock”: “1477062571”,
“facility_hash”: “3ca2e4a0693da5256106cd94c7f3ef80145e3cb6”,
“facility_name”: “”,
“id”: “ALK868-1476855045-airline-0195: 0”,
“gs”: “111”,
“heading”: “353”,
“hexid”: “77058D”,
“lat”: “40.05592”,
“lon”: “116.61813”,
“reg”: “4RALM”,
“squawk”: “7370”,
“updateType”: “A”,
altChange”: “C”,
“air_ground”: “A”


This appears to be a regression caused by one of the new ADS-B data providers we added this week. We will have this corrected soon.


Update: This should now be fixed on our servers. Let me know if you’re still seeing this problem.


still receiving json with duplicate key. last message had pitr 1477112320 (2 minutes before this posting). in a reconnect required?


Yes, you will need to reconnect to receive the new behavior.


that appeared to do the trick. thank you.