# ETag

A version fingerprint that lets clients skip downloading unchanged data.

## What is **ETag**?

An **ETag** is a version fingerprint of a response. Clients send it back with `If-None-Match`; if nothing changed, the server answers `304 Not Modified` with no body.

```text
ETag: "v7-a1b2c3"

GET /recipes/42
If-None-Match: "v7-a1b2c3"
→ 304 Not Modified
```

Level: Freelancer · [More Web Development terms at this level](https://www.ask-codey.com/glossary/subjects/web-development/freelancer)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/etag