MIME Type Checker

A MIME type (Multipurpose Internet Mail Extensions) is a standardized label that identifies the format of a file or network resource. You need to check MIME types to ensure web servers send correct Content-Type headers, validate uploaded files match expected formats, debug API content negotiation issues, and implement proper security controls for user-generated content. Incorrect MIME types cause browsers to misrender content, download files instead of displaying them, or execute dangerous files unexpectedly.

Enter the extension without the dot (like pdf or png) into the search field. The tool returns the canonical MIME type, all associated extensions, IANA registration status, security risk level, and ready-to-use HTTP headers. For extensions with multiple MIME types (like .xml), the most common web usage is shown first.

Yes. Enter any MIME type like application/json or image/webp and the tool returns all associated file extensions. This is useful when you receive a MIME type from an API or HTTP header and need to know what file extensions to expect or generate.

The risk indicator classifies file types by their potential for malicious use. Safe types (images, audio, plain text) cannot execute code. Caution types (JavaScript, SVG, PDF, archives) may contain active content or scripts that require careful validation. Danger types (executables, shell scripts, system binaries) can run arbitrary code and should never be accepted from untrusted sources without extreme scrutiny.

Paste the complete header value including parameters, such as application/json; charset=utf-8 or multipart/form-data; boundary=----WebKitFormBoundary. The parser extracts the base MIME type, validates syntax per RFC specifications, identifies charset and boundary parameters, and flags missing required parameters or unusual values.

IANA (Internet Assigned Numbers Authority) maintains the official registry of standard MIME types. Registered types follow established standards and have guaranteed uniqueness. Unregistered (vendor-specific or experimental) types may work in specific contexts but can cause interoperability issues. The tool marks IANA-registered types for confidence in standard compliance.

The tool uses fuzzy matching with Levenshtein distance to detect likely typos. If you enter jepg instead of jpeg, or yml instead of yaml, it suggests the closest valid matches. For truly unknown extensions, the tool recommends checking spelling or using the browse feature to explore similar categories.

Copy the Apache AddType or Nginx types block into your server configuration file. Apache directives go in httpd.conf or .htaccess; Nginx types belong in the http block of nginx.conf or a mime.types include file. After updating configuration, reload your web server to apply changes. These directives ensure your server sends correct Content-Type headers for all file types you serve.

They are synonymous. "MIME type" is the historical name from email standards. "Content-Type" is the HTTP header that carries this value. Modern specifications prefer "media type" as the generic term. The tool accepts and returns all these variations interchangeably.

Some text-based formats contain executable code or active content. JavaScript files are text but execute in browsers. SVG images can contain JavaScript. Shell scripts are text but execute in system shells. The caution rating reminds developers to apply appropriate sanitization even for seemingly "plain text" formats.

Check the risk level before accepting any upload. Reject Danger types entirely unless you have specific executable handling requirements. For Caution types, validate file contents match extension claims (magic number checking), scan with antivirus, and serve with Content-Disposition: attachment to prevent browser execution. Never trust client-provided MIME types alone—verify with server-side detection.

Charset specifies text encoding (utf-8, iso-8859-1) and is required for proper character rendering. Boundary delimits parts in multipart messages like form submissions or email. Base64 indicates binary-to-text encoding. The tool shows which parameters are typical for each MIME type and generates properly formatted headers including them.

Some extensions are ambiguous. .xml files could be application/xml, text/xml, or specific formats like image/svg+xml. .docx files are technically application/vnd.openxmlformats-officedocument.wordprocessingml.document but may be served as application/octet-stream. The tool shows the most common web-appropriate type first while listing alternatives.

No—this tool performs lookup and validation based on names and headers, not content analysis (magic numbers). For content-based detection, use the Unix file command, libmagic, or server-side libraries like python-magic. This tool complements content detection by providing the metadata and configuration knowledge those tools lack.

The database includes all IANA-registered types as of 2024 plus widely-used de facto standards (WebP, AVIF, modern font formats). The tool is updated when new types achieve significant web platform adoption. For bleeding-edge experimental types, consult the IANA registry directly or propose additions via the project repository.