# Deep Dive: Telemetry cardinality in the Apollo GraphOS Router

DevFeed: [Deep Dive: Telemetry cardinality in the Apollo GraphOS Router](<https://devfeed.tech/articles/deep-dive-telemetry-cardinality-in-the-apollo-graphos-router-23529.md>)

Original publisher: [Read original article](<https://www.apollographql.com/blog/telemetry-cardinality-in-the-apollo-graphos-router>)

Author: Nick Marsh

Published: 2026-02-10T09:00:00Z

Content type: tutorial

Language: en

Sources: [Apollo Blog](<https://devfeed.tech/sources/apollo-blog.md>)

Topics: [GraphOS](<https://devfeed.tech/topics/graphos.md>), [OpenTelemetry](<https://devfeed.tech/topics/opentelemetry.md>), [telemetry](<https://devfeed.tech/topics/telemetry.md>), [Instrumentation](<https://devfeed.tech/topics/instrumentation.md>), [SDK](<https://devfeed.tech/topics/sdk.md>), [Rust](<https://devfeed.tech/topics/rust.md>)

Tags: [announcement](<https://devfeed.tech/tags/announcement.md>), [cardinality](<https://devfeed.tech/tags/cardinality.md>), [config](<https://devfeed.tech/tags/config.md>), [graphos](<https://devfeed.tech/tags/graphos.md>), [instrumentation](<https://devfeed.tech/tags/instrumentation.md>), [metric](<https://devfeed.tech/tags/metric.md>), [metrics](<https://devfeed.tech/tags/metrics.md>), [observability](<https://devfeed.tech/tags/observability.md>), [opentelemetry](<https://devfeed.tech/tags/opentelemetry.md>), [rust](<https://devfeed.tech/tags/rust.md>), [scale](<https://devfeed.tech/tags/scale.md>), [sdk](<https://devfeed.tech/tags/sdk.md>), [telemetry](<https://devfeed.tech/tags/telemetry.md>), [traces](<https://devfeed.tech/tags/traces.md>)

## AI overview

This technical article explains how the Apollo GraphOS Router uses OpenTelemetry for metrics and traces, including instrumentation, metric providers, readers, and exporters. It also describes the OpenTelemetry SDK's 2,000-cardinality limit and how reaching that limit affects metric attributes.

## Source excerpt

Learn how telemetry works in the Apollo GraphOS Router, from OpenTelemetry instrumentation to metric exporters. Understand cardinality limits, diagnose overflow issues, and tune your router config for production-scale observability.