> For the complete documentation index, see [llms.txt](https://www.pranaypourkar.co.in/the-programmers-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.pranaypourkar.co.in/the-programmers-guide/api/api-styles-and-protocols/rest-api/http-headers/content-type.md). # Content Type ## About The `Content-Type` is an **HTTP header** used to indicate the **media type** (also called MIME type) of the data being sent in the **body** of an HTTP request or response. It tells the server or client how to **interpret the content** of the message body. ## Why is Content-Type Important? APIs often exchange data in formats like JSON, XML, HTML, plain text, etc. The `Content-Type` header helps ensure that: * The **server knows how to parse the incoming request body** * The **client knows how to handle the response body** If the `Content-Type` is missing or incorrect, the receiver may fail to understand or parse the data correctly. ## Usage ### In a **Request** When a client (like Postman, browser, or frontend app) sends data to the server, it must specify the format using the `Content-Type` header. Example: ``` POST /api/users Content-Type: application/json { "name": "John", "email": "john@example.com" } ``` The server will use this header to determine how to read the request body — in this case, as JSON. ### In a **Response** When the server responds, it can also set the `Content-Type` to tell the client what format the response body is in. Example: ``` HTTP/1.1 200 OK Content-Type: application/xml John john@example.com ``` ## Possible Content-Type Values

Content-Type	Description
`application/json`	JSON data. Most common format in REST APIs.
`application/xml`	XML data. Used in older APIs and some enterprise systems.
`text/plain`	Plain text data with no formatting.
`text/html`	HTML content, used in web pages.
`application/x-www-form-urlencoded`	Form data encoded in key-value pairs (like `key=value&key2=value2`). Default for HTML forms.
`multipart/form-data`	Used for form submissions that include files (e.g., image uploads).
`application/octet-stream`	Binary data; generic for any file (used in downloads or file streams).
`application/pdf`	PDF files.
`application/zip`	ZIP compressed files.
`application/javascript`	JavaScript files.
`text/css`	CSS stylesheets.
`image/png`	PNG image.
`image/jpeg`	JPEG image.
`image/gif`	GIF image.
`image/svg+xml`	SVG (Scalable Vector Graphics) in XML format.
`audio/mpeg`	MP3 audio format.
`audio/wav`	WAV audio format.
`video/mp4`	MP4 video format.
`video/x-msvideo`	AVI video format.
`application/vnd.api+json`	JSON:API specification format.
`application/graphql`	GraphQL query format.
`application/ld+json`	Linked Data using JSON (used in semantic web, schema.org).
`application/soap+xml`	SOAP XML format (used in SOAP-based APIs).
`application/vnd.ms-excel`	Microsoft Excel (XLS) file.
`application/vnd.openxmlformats-officedocument.spreadsheetml.sheet`	Microsoft Excel (XLSX) file.
`application/msword`	Microsoft Word (DOC) file.
`application/vnd.openxmlformats-officedocument.wordprocessingml.document`	Microsoft Word (DOCX) file.
`application/x-yaml`	YAML format (not standard but used in APIs and config services).
`application/x-protobuf`	Protocol Buffers (binary serialization format).
`application/x-ndjson`	Newline-delimited JSON (used in streaming APIs).

## Relation to Accept Header * `Content-Type` is used to indicate the **format being sent**. * `Accept` is used to indicate the **format expected in response**. Example: ``` POST /api/data Content-Type: application/json Accept: application/xml ``` This means: * "I’m sending you JSON" * "Please respond with XML" ## Content-Type in API Frameworks (like Spring) In Java Spring (or similar frameworks): * To define what our API **accepts**, use `consumes = MediaType.APPLICATION_JSON_VALUE` * To define what our API **returns**, use `produces = MediaType.APPLICATION_XML_VALUE` Example: ```java @PostMapping(value = "/users", consumes = "application/json", produces = "application/xml") public UserResponse createUser(@RequestBody UserRequest user) { ... } ``` ## What Happens if Content-Type is Missing ? * The server might reject the request (`415 Unsupported Media Type`) * The server might default to another format and incorrectly parse the data * The client might misinterpret the response content --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://www.pranaypourkar.co.in/the-programmers-guide/api/api-styles-and-protocols/rest-api/http-headers/content-type.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.