---
title: Sidecar
test: n/a
---

A sidecar, generally, is a container that runs alongside a primary application to provide additional functionality.
In Istio, sidecar mode is a [data plane mode](/docs/reference/glossary/#data-plane-mode) that runs an [Envoy](/docs/reference/glossary/#envoy) proxy alongside each
[Pod](/docs/reference/glossary/#pod).