Estimate Concurrent WebSocket Connections From Memory

How to Use This Tool

Reserve host memory before dividing the remaining budget by per-connection state. Connection counts look lightweight until buffers, subscriptions and application session state accumulate across hundreds of thousands of sockets.

Why WebSocket Capacity needs more than a raw total

Measure quiet and busy connections separately because queued messages and compression contexts can dominate the steady-state socket object. For this page, the useful comparison is planning open connections, not whichever input happens to be largest. The WebSocket Capacity result answers the decision in the heading and should not be reused as a score for a different workflow.

The exact WebSocket Capacity formula

Connections equal floor((available memory × (1 − reserve) − baseline memory) converted to KB ÷ KB per connection). The visible fields are Memory available to service, Baseline service memory, Memory per open connection and Operational reserve. For WebSocket Capacity, read each printed unit before entry and make the values describe one transaction, cohort or reporting window. If those scopes differ, the displayed planning open connections may be arithmetically valid but operationally meaningless.

Interpreting planning open connections

Cap below the estimate and validate file descriptors, event-loop latency, network bandwidth and reconnect storms independently. The ten-percent comparison is deliberately narrow: it tests the influence of memory available to service and is neither a forecast nor a confidence interval. Preserve the values used, their dates and the resulting decision so a later reviewer can reproduce why WebSocket Capacity supported the choice.

What this WebSocket Capacity model leaves out

Kernel buffers, TLS state, queued messages, compression, file-descriptor limits and CPU are excluded unless included in measured KB. That is where WebSocket Capacity stops being trustworthy. If an excluded factor could reverse planning open connections, extend the model explicitly or use the authoritative account system instead of hiding the factor inside an unexplained adjustment.

Evidence and independent verification

The reference reviewed for WebSocket Capacity is MDN — WebSocket API. MDN — WebSocket API supports the named definition or rule but does not supply private values for planning open connections. Before acting on the result, reconcile the worked example with the relevant dashboard, invoice, export or measurement.

Private, reproducible calculation

WebSocket Capacity runs its arithmetic in the current browser tab and requests no login or API key. That keeps the WebSocket Capacity inputs away from the site's calculation server, while leaving the user responsible for detecting stale data or a changed platform rule. When an assumption changes, reopen MDN — WebSocket API and rerun the saved WebSocket Capacity scenario.