YouTube Live Streaming API rate error: how to find out, which exactly quota is exceeded?

Question

We develop a server application that publishes meetings from internal system into YouTube live events. It accesses API on behalf of its only user, the channel owner, and authenticates with both API key and OAuth 2.0 Client ID.

The code creates live events as described in the guide:

broadcast = youtube.liveBroadcasts().insert(...).execute()
stream = youtube.liveStreams().insert(...).execute()
youtube.liveBroadcasts().bind(
    part='id,status', id=broadcast['id'], streamId=stream['id']
).execute()

After about 15-25 created live events YouTube Live Streaming API starts returning error userRequestsExceedRateLimit:

{
  "error": {
    "code": 403,
    "message": "User requests exceed the rate limit.",
    "errors": [
      {
        "message": "User requests exceed the rate limit.",
        "domain": "youtube.liveBroadcast",
        "reason": "userRequestsExceedRateLimit"
      }
    ]
  }
}

After one day of waiting the very first request sent was rejected with the same error. The Quota page in console shows two failed requests, far from reaching any limits:

How to find out which limit has been exceeded?

UPDATE 1: the quota did not reset on midnight west coast USA, the limit was active at least until 18:30 UTC next day (10:30 PST). Apparently, the quota was reset 24 hours after exceeding the limit.

Also, while calls to create live broadcasts were rejected with error, the calls for listing objects were working. It looks like there could be not a single "unit quota", but rather multiple quotas for different "domains".

UPDATE 2: the quota increase request was approved, and quota was increased, but that did not change the limit of live events that can be created per day. The API starts returning the same error after inserting 15-25 live broadcasts.

Again, when the API already started returning userRequestsExceedRateLimit for liveBroadcasts().insert(), other calls could still be sent: deleting all created events works, listing channel contents works, as if the quota was not reached at all.

Answer 1

The key here is user.

User requests exceed the rate limit.

You are using all your Queries per minute per user.

cost based vs query based

The YouTube API doesn't work like the other apis, its cost based not query based. YouTube Data API (v3) - Quota Calculator

Yes the page says query based that's just because they didn't change the UI for a single api.

See: Intro to YouTube API and Cost-Based Quota: Everything You Need to Know

It is not the number of calls it is the cost of your calls