Content-Length Inspect

Parse and diagnose HTTP headers and routing signals in your browser. No input is sent to a server. Use it for first-pass observation-gap 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-Length or Response Headers and click “Parse”. It summarizes size and related headers.

Notes (this tool)

  • Accepts Content-Length: header lines (multi-line paste is OK).
  • If Content-Length is missing, Transfer-Encoding: chunked may be used.

About this page

What does this tool do?

Split Content-Length to list response size (bytes) and related header checks.

Useful for diagnosing size mismatches, download issues, and compression/chunked transfer.

Basics (role of Content-Length)

  • Content-Length is the response body size in bytes.
  • With Transfer-Encoding: chunked, Content-Length is typically omitted.
  • With Content-Encoding, it usually reflects the compressed size.

Input examples

  • Content-Length: 12345
  • Paste full Response Headers

Relation to chunked transfer

With Transfer-Encoding: chunked, the size is not known upfront, so Content-Length is usually absent.

Common pitfalls

  • Content-Length does not match actual body size
  • Using pre-compression size with Content-Encoding
  • Sending both chunked and Content-Length

Debugging workflow (recommended)

  • Extract Content-Length via Response Headers Parser
  • Summarize size and related headers with this tool
  • Check compression with Content-Encoding Inspect
  • Content-Encoding Inspect
  • Response Headers Parser
  • Request Headers Parser

What this tool does

  • Summarize Content-Length values
  • Clarify relation to chunked/compression
  • Highlight related headers to verify

Operational notes

  • Intermediaries may rewrite headers. Compare captures from equivalent points.
  • Confirm final decisions with server logs and configuration such as trusted proxy and routing.

Referenced specs

  • RFC 9110 (HTTP Semantics)
  • MDN: Content-Length
  • MDN: Transfer-Encoding

FAQ

Is it a problem if Content-Length is missing?

It’s normal when using chunked transfer. For fixed-length responses, it is commonly included.

Is Content-Length pre- or post-compression?

With Content-Encoding, it is generally the compressed size.

References

  1. RFC 9110
  2. MDN: Content-Length
  3. MDN: Transfer-Encoding

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

  1. Accept-Ranges Inspect — Parse Accept-Ranges and inspect partial-content support
  2. Range Request Builder — Build Range request headers
  3. Content-Range Inspect — Parse Content-Range and inspect returned ranges
  4. If-Range Inspect — Parse If-Range and inspect conditional range behavior
  5. Accept-Encoding Inspect — Parse Accept-Encoding and inspect compression negotiation
  6. Content-Encoding Inspect — Parse Content-Encoding to verify applied compression
  7. Transfer-Encoding Inspect — Parse Transfer-Encoding and inspect transfer mode
  8. Vary Inspect — Parse Vary and visualize cache variation keys

Range/Partial Content

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

Compression/Transfer

Use Accept/Content/Transfer-Encoding plus Vary to isolate compression mismatches