Both

HTTP Content-Length Header

Indicates the size of the response body in bytes. Helps the client know how much data to expect and when the response is complete.

Purpose

Tells the receiver the exact size of the message body in bytes for proper data handling.

Content-Length: <bytes> Example: Content-Length: 348

Code Examples

See how to use the Content-Length header in different tools and languages.

curl -I https://api.example.com/data
# Response header:
# Content-Length: 2847

curl -H "Content-Length: 42" -X POST -d '{"key":"value"}' https://api.example.com/data

Related Headers

Content-Type

Indicates the media type (MIME type) of the resource being sent. Tells the client how to interpret the response body.

Content-Encoding

Indicates which compression algorithm was applied to the response body. The client must use the same algorithm to decompress the data.

Transfer-Encoding

Specifies the transfer encoding applied to the message body. Chunked encoding is used when the response size is not known in advance.

Test Your APIs

API Response Time Checker

Test your APIs and inspect response headers in real-time

HTTP Headers Reference

Complete reference of all HTTP request and response headers

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