Quick answer
MongoDB Atlas documents concurrent connections as 500. Atlas connection limits apply per node or mongos depending on topology.
Verified Aug 22, 2026Official source
Current limits
| Constraint | Current value | Scope | Verified source |
|---|---|---|---|
| concurrent connectionsAtlas connection limits apply per node or mongos depending on topology. | 500 | Free cluster | MongoDBAug 22, 2026 |
Why does this limit matter?
Serverless application pools can multiply quickly across instances and consume the free cluster limit.
This value is scoped to Free cluster; a different plan, runtime, model, endpoint, region, or account can produce a different effective constraint.
What should you check?
- Sum driver maxPoolSize across live application instances and inspect Atlas connections.
- Confirm the exact plan, model, runtime, endpoint, region, and account that serve the failing workload.
- Record the observed value, response headers or configuration, timestamp, and source without logging secrets.
Important caveats
- Some connections are reserved, and read preference affects how client pools distribute.
- Treat the official source and live account configuration as authoritative if they differ from this verified snapshot.
HyperObserve reports the documented platform constraint. Your application, SDK, gateway, provider, region, or account can impose a lower effective limit.
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