Accept-Ranges 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 Accept-Ranges or Response Headers and click “Parse”. It summarizes range support.

Notes (this tool)

  • Accepts Accept-Ranges: header lines (multi-line paste is OK).

About this page

What does this tool do?

Split Accept-Ranges to show whether Range requests are supported.

Useful for troubleshooting streaming, resume downloads, and partial fetch.

Basics (Accept-Ranges and Range)

  • Accept-Ranges: bytes indicates Range support.
  • Accept-Ranges: none indicates no support.
  • Successful Range requests return 206 Partial Content.

Input examples

  • Accept-Ranges: bytes
  • Accept-Ranges: none
  • Paste full Response Headers

Common pitfalls

  • Missing Accept-Ranges (some servers still support ranges)
  • Range sent but 200 returned (effectively not supported)
  • CDN alters range behavior

Debugging workflow (recommended)

  • Extract Accept-Ranges via Response Headers Parser
  • Summarize support with this tool
  • Build Range headers with Range Request Builder
  • Range Request Builder
  • Content-Length Inspect
  • Response Headers Parser

Recommendations (practical)

  • Enable Accept-Ranges for large file delivery
  • If you accept Range, return Content-Range and 206
  • Pair with ETag/Last-Modified for safety

What this tool does

  • Summarize Accept-Ranges values
  • Help determine range support

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: Accept-Ranges

FAQ

If Accept-Ranges is missing, is Range unsupported?

Not necessarily, but it makes support unclear; it’s safer to include it.

What status code is returned on a successful Range request?

206 Partial Content.

References

  1. RFC 9110
  2. MDN: Accept-Ranges

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

  1. Range Request Builder — Build Range request headers
  2. Content-Length Inspect — Parse Content-Length and inspect size consistency
  3. Content-Range Inspect — Parse Content-Range and inspect returned ranges
  4. If-Range Inspect — Parse If-Range and inspect conditional range behavior

Range/Partial Content

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