HTTP Request Headers
Common HTTP request headers and their purposes.
Common HTTP request headers with a description and an example value: Accept, Accept-Language, Accept-Encoding, Authorization, Cache-Control, Content-Type, Cookie, Host and User-Agent, plus Origin, Referer, Range, conditional headers and proxy headers.
Use it when
- You need the purpose and format of a request header.
- You are debugging a request in browser developer tools.
Watch out for
- Some headers can be set only by the browser; scripts cannot set forbidden header names.
- X-Forwarded-For can be spoofed by clients unless a trusted proxy overwrites it.
The data
20 rows
| Header | Description | Example |
|---|---|---|
| Accept | Content types the client can process. | application/json, text/html |
| Accept-Language | Preferred languages for the response. | en-US, en;q=0.9 |
| Accept-Encoding | Acceptable content encodings. | gzip, deflate, br |
| Authorization | Credentials for authentication. | Bearer eyJhbGci... |
| Cache-Control | Caching directives for request and response. | no-cache, max-age=3600 |
| Content-Type | Media type of the request body. | application/json; charset=utf-8 |
| Content-Length | Size of the request body in bytes. | 1234 |
| Cookie | Previously set cookies to send back to the server. | session_id=abc123 |
| Host | Domain name of the server. | api.example.com |
| User-Agent | Client application identifier. | Mozilla/5.0 ... |
| X-Request-ID | Custom header for request tracing. | req-abc123def456 |
| If-None-Match | Conditional request using ETag. | "33a64df551425fcc55e4d42a148795d9f25f89d4" |
| Origin | The origin (scheme, host, port) that initiated a cross-origin or POST request. | https://example.com |
| Referer | The URL of the page that linked to the resource; the misspelling is historical. | https://example.com/page |
| Range | Asks for only part of a resource, used for resumable downloads and media seeking. | bytes=0-1023 |
| If-Modified-Since | Conditional request that returns 304 Not Modified if the resource has not changed since the date. | Wed, 21 Oct 2015 07:28:00 GMT |
| If-Match | Makes a request conditional on the resource's ETag matching, used to avoid lost updates. | "33a64df551425fcc" |
| X-Forwarded-For | De facto header listing the originating client IP and proxies a request passed through. | 203.0.113.5, 198.51.100.7 |
| Forwarded | Standardized header (RFC 7239) carrying proxy information such as the client address and protocol. | for=203.0.113.5;proto=https |
| Sec-Fetch-Site | Browser-set header indicating how the request's origin relates to the target, useful for blocking cross-site requests. | same-origin |
Fields
The shape of this dataset, read from the data itself: every column, its type and a real value. Agents can use this to plan a query without fetching the whole document.
| Section | Field | Type | Example |
|---|---|---|---|
| data | header | string | Accept |
| data | description | string | Content types the client can process. |
| data | example | string | application/json, text/html |
Fetch the same bytes
The static files contain the same reference rows as the API, with no API rate limit. Live metadata, such as view counts, may differ. Use the API for content negotiation; use the static files for a cacheable snapshot.
curl "https://yjtoon.com/api/dataset/http-request-headers?format=toon"
const res = await fetch( "https://yjtoon.com/static-data/dataset/http-request-headers.toon" ); const toon = await res.text();
Rate limit: 120 requests per minute per IP, no key and no signup. API reference →