Where is it in the docs? Can you share a link?

“In push mode, you can set a maximum concurrency per consumer group. This limits how many messages can be in-flight simultaneously for that group. If the limit is reached, Vercel holds back delivery until an in-flight message is acknowledged or its lease expires.“

https://vercel.com/docs/queues/concepts

We are encountering this limitation in a production-like workload using @vercel/queue 0.5.0 and a JavaScript queue/v2beta push consumer.

One publish operation created 110 messages. Vercel started all 110 first-delivery callback invocations within 18.354 seconds. The consumer calls a rate-limited downstream GraphQL service, and 49 deliveries failed with HTTP 429 and required retries.

We need to configure the push consumer group with a maximum concurrency of 1.

The documentation states:

“In push mode, you can set a maximum concurrency per consumer group.”

However, we cannot find a supported configuration surface:

• The consumer group under Project → Observability → Queues is read-only.
• The documented queue/v2beta trigger schema exposes topic, retryAfterSeconds, and initialDelaySeconds, but no maxConcurrency.
• @vercel/queue does not expose a push consumer-group update method.
• Vqs-Max-Concurrency appears to apply only to poll-mode receive requests.

Could you please confirm:

1. Is push-mode maximum concurrency currently available?
2. If it is internally configurable, can Vercel set our consumer group limit to 1?
3. Is there a planned supported configuration through vercel.json, the dashboard, or an API?