Content-Range Inspect

Analyze cache-related headers across layers. No input is sent to a server. Use it for first-pass revalidation and CDN mismatch troubleshooting.

Status

Runs in your browser. No input is sent to a server. Use this as a first-pass diagnostic step.

How to use

Paste Content-Range or Response Headers and click “Parse”. It summarizes range and total size.

Notes (this tool)

  • Accepts Content-Range: header lines (multi-line paste is OK).

About this page

What does this tool do?

Split Content-Range to list returned range (start-end) and total size.

Useful for validating Range requests (206/416).

Basics (role of Content-Range)

  • Content-Range is returned with 206 Partial Content.
  • Format: bytes=start-end/total.
  • For invalid ranges, 416 may return bytes */total.

Input examples

  • Content-Range: bytes 0-1023/4096
  • Content-Range: bytes */4096
  • Paste full Response Headers

Common pitfalls

  • 206 returned without Content-Range
  • Returning a fixed total when unknown
  • Mismatch between Content-Range and Content-Length
  • Multiple ranges requested but only a single Content-Range returned

Reading 206 vs 416

  • 206 Partial Content: a valid range is returned
  • 416 Range Not Satisfiable: invalid range; Content-Range: bytes */total may be returned

Relation to Content-Length

For 206, Content-Length is the size of the returned range. The total size is in Content-Range /total.

Debugging workflow (recommended)

  • Check support with Accept-Ranges Inspect
  • Build Range with Range Request Builder
  • Parse Content-Range with this tool
  • Accept-Ranges Inspect
  • Range Request Builder
  • Content-Length Inspect
  • If-Range Inspect
  • Response Headers Parser

Recommendations (practical)

  • Always return Content-Range with 206
  • Keep Content-Length consistent
  • Pair with ETag/Last-Modified for safety

What this tool does

  • Parse and display Content-Range
  • Summarize total size

Operational notes

  • Cache behavior changes across browser, CDN, and proxy layers, so compare captures from the same observation point.
  • Header-only diagnosis may be insufficient. Also review application cache invalidation strategy and key design.

Referenced specs

  • RFC 9110 (HTTP Semantics)
  • MDN: Content-Range

FAQ

What does Content-Range look like for 416?

It is commonly returned as bytes */total.

What if total is *?

It indicates the total size is unknown.

References

  1. RFC 9110
  2. MDN: Content-Range
  3. MDN: 206 Partial Content
  4. MDN: 416 Range Not Satisfiable

These links are generated from site_map rules in recommended diagnostic order.

  1. If-Range Inspect — Parse If-Range and inspect conditional range behavior
  2. Range Request Builder — Build Range request headers
  3. Accept-Ranges Inspect — Parse Accept-Ranges and inspect partial-content support
  4. Content-Length Inspect — Parse Content-Length and inspect size consistency

Range/Partial Content

Cross-check Range/Content-Range/If-Range to validate partial delivery