Is jetstream message count capped at 1 billion for a single stream?

[ftong2020]

We're using NATS internally as message bus and message queue. Great product, very happy about it. In term of message queue(Jetstream), we encoutered a limit by surprise.

One day, a service in our system went wild, starting to producing massive amount of message to a single stream. When we're still trying to figure out why, we found that some messages are discarded(can not figure out if it is latest message/oldest message). It was confusing at then beginning, but it turned out that message number is capped at 1 billion. For the tenant and the stream ,maxMessageSize and MaxMessages are all set to 0.

I can't find any documentation about the "1 billion cap" behavior. Is this by design? Or I miss configured somewhere?

1 billion is nothing small, but consumers do go down sometimes. it can be easily reached in a moderated system these days.

[wallyqs]

Hi @ftong2020, we would need more info about your setup or the type of stream that you are using as currently cannot think of an obvious limit, a limits based stream should be possible to have +1B msgs:

State:

            Host Version: 2.11.7
                Messages: 1,174,510,552
                   Bytes: 36 GiB
          First Sequence: 1 @ 2025-08-04 16:32:49
           Last Sequence: 1,174,510,552 @ 2025-08-04 19:54:14
        Active Consumers: 0
      Number of Subjects: 1

[ftong2020]

Let me try to reproduce.