How would you name a metric that measures gRPC response size?

Following Prometheus’smetric naming conventions, every metric should indicate:

Whatit measures (the quantity or event).

The unitof measurement inbase SI unitsas a suffix.

Since the metric measuresresponse size, the base unit isbytes. Therefore, the correct and compliant metric name is:

grpc_response_size_bytes

This clearly communicates that it measures gRPC response payload sizes expressed in bytes.

The _bytes suffix is the Prometheus-recommended unit indicator for data sizes. The other options violate naming rules:

_total is reserved for counters.

_sum is used internally by histograms or summaries.

Omitting the unit (grpc_response_size) is discouraged, as it reduces clarity.