Understand your file extensions

An .ai file is a proprietary vector graphics file format developed by Adobe Systems for representing single-page vector-based drawings in either the EPS or PDF formats. It is the standard format for Adobe Illustrator.

.avif (AV1 Image File Format) is a modern, royalty-free image format based on the AV1 video codec. It offers superior compression efficiency compared to JPEG, PNG, and even WebP, delivering high-quality images at significantly smaller file sizes.

A .bmp (Bitmap) file is a raster graphics image file format used to store bitmap digital images, independently of the display device. It typically stores color data for each pixel in the image without compression.

An .eps (Encapsulated PostScript) file is a legacy vector graphics file format used in professional printing and graphic design. It can contain both 2D vector graphics and bitmap images, and is designed to be included in other documents.

.gif (Graphics Interchange Format) is a bitmap image format that supports both static and animated images. It uses a limited color palette (up to 256 colors) and lossless LZW compression, making it the standard for simple animations, memes, and low-resolution graphics on the web.

.heic is a modern image format used by Apple devices that stores photos in a highly efficient container. It keeps image quality high while using less storage than JPG, especially for iPhone photos and bursts.

ICO is an image file format for computer icons in Microsoft Windows. Unlike standard image formats, a single .ico file can contain multiple images at different sizes and color depths, allowing the operating system to scale the icon appropriately.

.jpg (or .jpeg) is the most widely used image format for digital photography and web graphics. It uses lossy compression to significantly reduce file size while maintaining acceptable visual quality, making it ideal for storing and sharing colorful, complex images.

.png (Portable Network Graphics) is a raster graphics file format that supports lossless data compression. It was created as an improved, non-patented replacement for Graphics Interchange Format (GIF) and is the most widely used lossless image compression format on the Internet.

A .psd file is the native file format for Adobe Photoshop. It stores an image with support for most Photoshop imaging options, including layers with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings.

.svg (Scalable Vector Graphics) is an XML-based vector image format for two-dimensional graphics. Unlike raster images (JPG, PNG) that are made of pixels, SVGs are defined by mathematical formulas (lines, curves, shapes), allowing them to scale infinitely without losing quality.

.tiff (Tagged Image File Format) is a versatile raster graphics format popular among graphic artists, the publishing industry, and photographers. It is known for its high-quality, lossless compression, making it the standard for storing images that require editing without quality loss.

.webp is a modern image format developed by Google that delivers high-quality visuals at much smaller file sizes than traditional formats like JPG and PNG. It supports both lossy and lossless compression, plus optional transparency and animation.

.avi (Audio Video Interleave) is a multimedia container format introduced by Microsoft in 1992 as part of Video for Windows. It can hold both audio and video data in a single file but lacks many of the modern features and compression efficiencies found in newer formats like MP4 or MKV.

.flv (Flash Video) is a legacy video container format that was widely used to deliver streaming video over the web via Adobe Flash Player. It typically stores video encoded with codecs like Sorenson Spark, VP6, or H.264, along with audio (often MP3 or AAC) and basic metadata.

.m3u8 is a UTF-8 encoded playlist file used primarily by HTTP Live Streaming (HLS). It contains URLs or paths to media segments (usually TS or fragmented MP4 files), plus metadata tags that describe variant bitrates, resolutions, and encryption. The player reads the playlist and requests segments over HTTP, enabling adaptive streaming.

.mkv (Matroska Video) is a flexible, open-standard multimedia container format. It can store high-quality video, multiple audio tracks, soft subtitles, chapters, and attachments in a single file, making it a favorite for movies, series, and archival copies.

.mov (QuickTime Movie) is a multimedia container format developed by Apple for storing high-quality video, audio, and effects. It is widely used in professional video production, especially on macOS, for editing and mastering footage before export to delivery formats like MP4.

.mp4 (MPEG-4 Part 14) is the most widely used container format for digital video. It can store video, audio, subtitles, and metadata in a single file, and is supported by virtually every device, browser, and streaming platform.

.webm is an open, royalty-free media container format designed specifically for the web. It typically uses VP8/VP9 or AV1 for video and Opus or Vorbis for audio, providing efficient compression and high quality for HTML5 video playback.

.wmv (Windows Media Video) is a series of video codecs and corresponding container formats developed by Microsoft. It was widely used in the Windows ecosystem for streaming and downloaded video during the early 2000s, often wrapped in DRM (Digital Rights Management) for protected content.

.docx is the default file format for Microsoft Word documents created in Word 2007 and later. It uses Open XML formatting to store text, images, objects, and styles in a compressed ZIP-based container, making files smaller and more robust than the older .doc format.

.md files contain text written in Markdown, a lightweight markup language with plain text formatting syntax. It is designed to be easy to read and write, and is often converted to HTML for viewing.

.odt (OpenDocument Text) is an open, XML-based word processing format standardized by OASIS and ISO. It is the default format for LibreOffice Writer and many other open-source office suites, storing text, styles, images, and layout information inside a compressed ZIP container.

.pages is the native document format used by Apple Pages, part of the iWork suite. It stores rich text, images, styles, and layout information for word processing and simple page-layout documents, optimized for macOS, iOS, and iCloud workflows.

.pdf (Portable Document Format) is a versatile file format created by Adobe that presents documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.

.rtf (Rich Text Format) is a cross-platform document format created by Microsoft that stores text with basic formatting (fonts, sizes, colors, bold, italics) in a plain-text syntax. It is designed to be readable and editable on virtually any operating system and word processor.

.txt is the most basic file format that contains unformatted text. It uses standard character encoding (like ASCII or UTF-8) and contains no formatting, styles, images, or hidden metadata, ensuring it can be read by any computer or software.

.csv stands for Comma-Separated Values, a plain-text format for storing tabular data like spreadsheets, reports, or exports. Each line represents a row, and values in the row are separated by commas or other delimiters.

.xlsx is the default file format for Microsoft Excel spreadsheets created in Excel 2007 and later. It is an open XML-based format that stores data in worksheets, cells, rows, and columns, supporting formulas, charts, and complex formatting.

.bat files contain a series of commands to be executed by the Command Prompt (cmd.exe) on Windows operating systems. They are legacy scripts used for automating system tasks, launching programs, and file management, dating back to MS-DOS.

.cpp files contain source code written in C++, a powerful, high-performance programming language. It is an extension of the C language that adds object-oriented features, making it the standard for system software, game development, and performance-critical applications.

.cs files contain source code written in C# (pronounced 'C Sharp'), a modern, object-oriented, and type-safe programming language developed by Microsoft. It runs on the .NET framework and is widely used for building Windows applications, web services, and video games.

.css files contain Cascading Style Sheets, a language used to describe the presentation of a document written in a markup language like HTML. CSS handles the look and feel—layout, colors, fonts, and responsiveness—separating content from design.

A .env file is a simple text file containing key-value pairs of environment variables. It is used to configure applications by injecting settings (like API keys, database URLs, and debug flags) into the environment at runtime.

.go files contain source code written in the Go programming language (often referred to as Golang). Go is a statically typed, compiled language designed by Google for simplicity, reliability, and efficiency. It is famous for its built-in concurrency features (goroutines).

A .graphql (or .gql) file contains code written in the GraphQL Schema Definition Language (SDL) or executable GraphQL queries. It is used to define the structure of an API or to request specific data from a GraphQL server.

.html (HyperText Markup Language) is the standard markup language used to structure content on the web. HTML files define the layout, text, images, and interactive elements of web pages, and are interpreted directly by web browsers.

INI (Initialization) is a standard plain-text configuration file format. Originally the primary method for configuring Windows and its applications, it is still widely used today for software configuration (e.g., PHP's php.ini, Git's config, and desktop shortcuts).

.java files contain source code written in the Java programming language. Java is a class-based, object-oriented language designed to have as few implementation dependencies as possible, following the 'Write Once, Run Anywhere' (WORA) principle.

.js files contain JavaScript code, a programming language that enables interactive web pages. It is an essential part of web applications, allowing for dynamic content, controlling multimedia, animating images, and much more.

.json (JavaScript Object Notation) is a lightweight text format for structured data. It is easy for humans to read and write and easy for machines to parse and generate, making it the dominant format for web APIs, configuration files, and data interchange.

.kt files contain source code written in the Kotlin programming language. Kotlin is a modern, statically typed language that runs on the Java Virtual Machine (JVM). It is fully interoperable with Java but offers a more concise syntax and modern features like null safety.

.mjs files contain JavaScript code written using the ECMAScript Module (ESM) standard. This extension is used to explicitly tell Node.js and other tools to treat the file as a module, allowing the use of 'import' and 'export' statements instead of CommonJS 'require'.

.php files contain source code written in PHP (Hypertext Preprocessor), a widely-used open-source general-purpose scripting language that is especially widely suited for web development and can be embedded into HTML.

.ps1 files contain source code written in PowerShell, a cross-platform task automation and configuration management framework. It consists of a command-line shell and a scripting language built on top of the .NET Common Language Runtime (CLR).

.py files contain source code written in the Python programming language. Python is a high-level, interpreted language known for its readability and versatility, used in web development, data science, AI, and automation.

.rb files contain source code written in the Ruby programming language. Ruby is a dynamic, open-source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.

.rs files contain source code written in the Rust programming language. Rust is a multi-paradigm, high-level, general-purpose programming language designed for performance and safety, especially safe concurrency. It enforces memory safety without using a garbage collector.

.sh files contain a series of commands written in a scripting language for a command-line interpreter (shell), such as Bash (Bourne Again Shell), Zsh, or sh. They are used to automate tasks, install software, and manage system configurations on Unix-like operating systems (Linux, macOS).

A .sql file is a text file containing Structured Query Language (SQL) code. It typically contains commands to create database schemas (tables, views) or insert data, often generated as a database dump or export.

.swift files contain source code written in the Swift programming language. Developed by Apple, Swift is a powerful and intuitive programming language for iOS, iPadOS, macOS, tvOS, and watchOS. It is designed to be safe, fast, and interactive.

TOML (Tom's Obvious, Minimal Language) is a configuration file format that is easy to read due to its clear semantics. It is designed to map unambiguously to a hash table and is widely used in the Rust and Python ecosystems.

.ts files contain TypeScript code, a strongly typed superset of JavaScript developed by Microsoft. It adds optional static typing to the language, which helps catch errors during development before the code is run.

.wasm files contain WebAssembly binary code, a low-level assembly-like language with a compact binary format that runs with near-native performance in modern web browsers. It provides a compilation target for languages like C, C++, Rust, and Go, allowing them to run on the web.

.xml (Extensible Markup Language) is a text-based format for structured data that uses nested tags to describe custom, self-describing document types. It was widely used for configuration, documents, and system-to-system data exchange before JSON became dominant.

YAML (YAML Ain't Markup Language) is a human-readable data serialization standard that can be used in conjunction with all programming languages. It is often used for configuration files and in applications where data is being stored or transmitted.

.aac (Advanced Audio Coding) is a lossy audio compression format designed as the successor to MP3. It achieves similar or better perceived quality at lower bitrates, making it popular for streaming, downloads, and mobile use, especially in the MPEG-4 (MP4/M4A) ecosystem.

.flac (Free Lossless Audio Codec) is an open, royalty-free audio format that compresses audio data without any loss in quality. It reduces file size by 30–60% compared to uncompressed WAV while preserving every bit of the original recording.

An .m4a file is an audio-only MPEG-4 file. It typically uses Advanced Audio Coding (AAC) compression, offering better quality than MP3 at similar file sizes. It is the standard format for Apple devices and iTunes.

.midi / .mid (MIDI file) is a Standard MIDI File that stores musical performance data—notes, timing, velocity, instruments, and controller events—rather than recorded audio. It is more like a digital sheet music score that a synthesizer or virtual instrument plays back, producing sound based on the device's sound library.

.mp3 (MPEG Audio Layer III) is a lossy audio compression format that dramatically reduces file size while preserving acceptable sound quality. It became the de facto standard for music downloads, streaming, and portable audio players in the late 1990s and 2000s.

An .ogg file is an audio file that uses the Ogg container format, typically compressed with the Vorbis audio codec. It is a free, open-source alternative to proprietary formats like MP3 and AAC.

.wav (Waveform Audio File Format) is a raw or lightly compressed audio container developed by Microsoft and IBM. It is most commonly used to store uncompressed PCM audio, making it a standard for professional recording, editing, and archiving when maximum quality is required.

.7z is an open, high-compression archive format used by the 7-Zip utility. It supports a variety of compression algorithms, strong AES-256 encryption, and solid archiving, making it popular for power users who need maximum compression efficiency.

.gz (Gzip) is a compressed file format based on the DEFLATE algorithm. It compresses a single stream of data, often a TAR archive or text file, to reduce size for storage and transfer. Gzip is heavily used in Unix environments and on the web for HTTP content encoding.

.iso is a disc image format that stores a sector-by-sector copy of an optical disc such as a CD, DVD, or Blu-ray. Instead of containing individual files like a ZIP archive, an ISO recreates the entire filesystem layout of the original disc, including boot sectors and metadata.

.rar (Roshal Archive) is a proprietary archive format developed by Eugene Roshal. It offers strong compression, error recovery features, and solid archiving, and is most commonly associated with the WinRAR software on Windows.

.tar (Tape Archive) is a classic Unix archive format designed to bundle multiple files and directories into a single container. By itself, TAR does not compress data; it simply concatenates files with metadata, and is frequently combined with compressors like gzip (.tar.gz), bzip2 (.tar.bz2), or xz (.tar.xz).

.zip is the most widely used archive format for compressing and bundling files into a single container. It supports lossless compression, optional encryption, and is natively supported on all major operating systems.

.pptx is the default presentation file format for Microsoft PowerPoint created in PowerPoint 2007 and later. It uses the Office Open XML standard to store slides, text, images, audio, video, and transitions in a compressed ZIP-based container.

.epub (Electronic Publication) is an open, reflowable e-book format based on web standards. EPUB files bundle HTML, CSS, images, fonts, and metadata into a compressed container, allowing text to adapt to different screen sizes and reading preferences.

.mobi (Mobipocket) is an e-book format originally created by Mobipocket and later used by Amazon Kindle as a core part of its ebook ecosystem. It is a binary container format optimized for small devices and limited bandwidth, storing reflowable text, basic formatting, and embedded images.

.blend is the native project file format used by Blender. A .blend file can store complete 3D scenes including meshes, materials, textures, animations, cameras, lights, physics settings, and render configuration. It is primarily an authoring format for working inside Blender rather than a lightweight runtime delivery format.

.fbx (Filmbox) is a 3D scene format that can store meshes, materials, cameras, lights, skeletons, skinning, and animations in a single file. Originally developed by Kaydara and now owned by Autodesk, FBX is widely used in film, VFX, and game pipelines as an interchange format for complex 3D assets.

.gltf and .glb are part of the glTF (GL Transmission Format) standard, a modern 3D format designed for efficient transmission and loading in real-time applications. glTF stores 3D scenes including meshes, materials, textures, animations, and cameras in a compact form that is easy for graphics engines to consume.

.obj (Wavefront OBJ) is a text-based 3D geometry format that stores information about vertices, edges, faces, normals, and texture coordinates for 3D models. It is widely supported across 3D tools and engines, making it a common interchange format for meshes and static scenes.

.stl (Stereolithography) is a 3D geometry format that represents surfaces using a collection of triangles. It is one of the most common formats for 3D printing and rapid prototyping, describing only the outer shell of an object without color, textures, or material properties.

.apk (Android Package Kit) is the package format used to distribute and install Android apps. An APK file bundles the compiled app code, resources, assets, manifest metadata, and compiled bytecode into a single archive that Android devices and emulators can install.

.bin is a generic file extension for binary data that does not fit a more specific format. BIN files can represent disk images, firmware payloads, game assets, application data, or any other structured binary content defined by the software that uses them.

.dmg (Apple Disk Image) is a disk image format used on macOS to package file systems into a single mountable file. DMG files are commonly used to distribute macOS applications, archives, and installers, appearing to users as virtual disks that can be opened and browsed like physical drives.

.exe is the standard file extension for native executable programs on Microsoft Windows. An EXE file contains compiled machine code plus embedded resources and metadata that Windows uses to load and run desktop applications, utilities, installers, and background services.

.jar (Java Archive) is a ZIP-based package format used to bundle compiled Java bytecode (.class files), resources, and metadata into a single file. JARs are used for Java libraries, command-line tools, desktop apps, and components that run on the Java Virtual Machine (JVM).

.msi (Microsoft Installer) is a structured database file format used by Windows Installer to install, update, and remove software. An MSI package describes files, registry entries, shortcuts, and install logic in a standardized way that supports repair, rollback, and enterprise deployment.

.pkg files are macOS installer packages used by the Apple Installer system to install applications, system components, and configuration payloads. A PKG describes what files to place where, what scripts to run, and how to register the software with the operating system.

.cer files typically contain X.509 digital certificates that associate a public key with a domain, organization, or user identity. They are used in TLS/SSL, VPNs, code signing, and other secure communication scenarios, and may be encoded as either binary DER or text-based PEM.

.crt files typically contain X.509 digital certificates that bind a public key to a domain name, organization, or individual. They are used to establish trust for HTTPS, email security, VPNs, and other TLS-based protocols, and may be encoded in PEM (text) or DER (binary) form.

.key files typically contain private cryptographic keys used in TLS/SSL, VPNs, SSH, and other secure communication systems. A private key proves ownership of a certificate and enables decryption and digital signatures. KEY files may be stored as PEM-encoded text or other container formats and must be kept strictly confidential.

.pem files are text-based containers that store cryptographic material such as X.509 certificates, certificate chains, and private keys. The data inside is Base64-encoded and wrapped between header and footer lines like '-----BEGIN CERTIFICATE-----' and '-----END CERTIFICATE-----', making PEM easy to copy, paste, and transport as text.

.pub files typically contain public cryptographic keys. In SSH, a .pub file stores the public half of an asymmetric key pair, which servers or services use to verify signatures from the corresponding private key. Public keys can be shared broadly and do not need to be kept secret, but they must remain correctly paired with their private counterpart.

EOT (Embedded OpenType) is a legacy font format designed by Microsoft specifically for use on the web. It was the first format to enable custom fonts on websites via the `@font-face` rule in Internet Explorer.

OTF (OpenType Font) is a scalable computer font format built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. It was developed jointly by Adobe and Microsoft.

TTF (TrueType Font) is a font standard developed by Apple and Microsoft in the late 1980s. It is the most common format for fonts on both macOS and Windows operating systems and can be resized to any size without losing quality.

WOFF (Web Open Font Format) and its successor WOFF2 are font formats specifically designed for use on web pages. They are essentially OpenType or TrueType fonts with compression and additional metadata, enabling faster loading times and bandwidth savings.