File extensions
109 extensions currently documented.
- .3gpvideo
A multimedia container from 3GPP, designed for mobile-era phones and low-bitrate clips.
- .7zarchive
An open-source archive format known for high compression ratios via LZMA2. Typically smaller than ZIP for the same payload.
- .aacaudio
MP3's successor — higher audio quality at the same bitrate, and the default codec on YouTube, iTunes Store, and digital broadcasting.
- .aiffaudio
Apple's uncompressed audio format, dating back to the original Macintosh. Still a workhorse in music production.
- .apkexecutable
The distribution package for Android apps. Internally a ZIP archive holding DEX bytecode, resources, and a manifest.
- .asstext
A styled subtitle format that became the de-facto standard in anime fansubs and VOCALOID MVs. Descends from the original SSA and supports rich typography.
- .avivideo
Microsoft's original video container, heavily used in the Windows 98 era and still common on older camcorders and archival footage.
- .avifimage
A next-generation image format built on the AV1 codec. Smaller files than WebP with support for transparency, HDR, and animation.
- .batexecutable
A Windows batch script run by the Command Prompt. Double-clicking executes the commands inside — and therefore can do anything a user can.
- .bindata
A catch-all extension for raw binary data — firmware images, disk images, ROMs, memory dumps, and so on.
- .bmpimage
The uncompressed bitmap format that originated on Windows. Simple to parse and fast to render, but produces huge files.
- .bz2archive
A Burrows-Wheeler compression format. Denser than gzip but slower; xz and 7-Zip have largely overtaken it in modern Linux distributions.
- .ccode
C language source from 1972. Foundation of the Linux kernel, all major databases, and countless system programs.
- .cabarchive
Windows' internal archive format. Still used to deliver drivers, Windows Update payloads, and MSI package contents.
- .cbrarchive
The RAR-backed sibling of CBZ. Common in Western comic communities for years, where WinRAR tooling is ubiquitous.
- .cbzarchive
A ZIP-based container for comics and manga. Just numbered image files inside a ZIP — popular for doujinshi, scanned manga, and self-hosted comic libraries.
- .chmdocument
Microsoft's help file format — HTML plus assets compressed with LZX. Widely used for online help in Windows software since 1998. Still actively distributed in China, Japan, and Korea.
- .cppcode
C++ source. Still dominant in operating systems, game engines, finance, and embedded work where performance matters.
- .cssweb
The styling language for the web. Paired with HTML it controls colour, layout, animations, and media queries.
- .csvdata
A plain-text tabular format with comma-separated fields. The lowest-common-denominator for exchanging tables between spreadsheets, databases, and scripts.
- .datdata
A catch-all extension meaning 'some kind of data'. Game saves, email TNEF, app logs — all hide behind `.dat`.
- .debexecutable
The package format for Debian-based Linux distributions (Ubuntu, Mint, etc.). Installs, upgrades, and removes software via dpkg / apt.
- .dllexecutable
A shared library on Windows. Loaded by `.exe` processes to expose functions. DLLs are never run on their own — always loaded into a host.
- .dmgarchive
macOS disk image format. The default for distributing apps — double-click to mount, drag the `.app` to Applications to install.
- .docdocument
The pre-2007 binary Word format (Compound File Binary). Still circulates in government and SMB workflows and carries a high malware-delivery risk because of embedded macros.
- .docxdocument
The default Word document format since Word 2007. Under the hood it is a ZIP package of XML and media — portable enough that most apps can open it.
- .envdata
A file of environment variables loaded at app startup. The `.env` convention is universal in modern development for API keys and DB URLs.
- .epsimage
A vector image in PostScript. Still common in print shops and older design pipelines for delivering logos and illustrations.
- .epubdocument
The IDPF / W3C standard for e-books. Under the hood it is XHTML + CSS + metadata inside a ZIP — designed for reflowable text.
- .exeexecutable
A native Windows executable. Double-clicking launches the program. Disguised EXEs are one of the most common malware delivery paths.
- .flacaudio
Lossless audio compression that reduces CD-quality recordings to roughly half the size of WAV. The de-facto choice for music archival.
- .flvvideo
The video format built for Adobe Flash. Ruled web video from early YouTube through the mid-2010s; legacy after Flash's end-of-life.
- .gifimage
A lossless raster format with a 256-colour palette and limited animation support. Still ubiquitous on social feeds and chat reactions.
- .gocode
Source for Google's Go language. Known for lightweight goroutine concurrency and statically-linked single-binary output.
- .gzarchive
A gzip-compressed single file. Combined with tar it forms `.tar.gz`, the most common Linux distribution archive.
- .hcode
A C or C++ header file. Declares types, function prototypes, and macros pulled into other sources via `#include`.
- .heicimage
The default image format on iPhone cameras. Roughly half the size of JPEG at similar quality, but can be awkward to open outside of Apple platforms.
- .htmlweb
The source of a web page. A browser renders it; a text editor shows you the markup underneath.
- .icoimage
The native Windows icon format. A single file can hold multiple resolutions and colour depths — still the default for desktop icons and legacy web favicons.
- .inidata
A classic key-value configuration format. Still common in Windows apps and legacy Unix tools for profiles and settings.
- .ipaexecutable
The distribution package for iOS apps. A ZIP containing the `.app` bundle, metadata, and a provisioning profile.
- .isoarchive
A bit-for-bit image of a CD/DVD/Blu-ray. Used for OS installers, recovery media, and backups.
- .javacode
Source for the Java language. Compiles to `.class` bytecode that runs on the JVM.
- .jpgimage
A lossy compression format optimised for photographs — the default on smartphone cameras and web galleries. `.jpg` and `.jpeg` are identical; the three-letter form is a DOS-era holdover.
- .jsweb
Source for the language that runs the web — in browsers and on servers (Node.js, Bun, Deno). Central to interactive UIs and modern tooling.
- .jsondata
A lightweight data-interchange format. The de-facto standard for config files, API payloads, and database dumps.
- .jxlimage
The JPEG committee's 2022 next-generation image format. Losslessly transcodes existing JPEGs and supports HDR, wide gamut, and animation. Browser support is still uneven.
- .keydocument
The native format for Apple's Keynote presentation app. Known for smoother transitions and cleaner typography than PowerPoint.
- .ktcode
JetBrains' JVM language. Google's preferred language for Android and a more concise alternative to Java on the JVM.
- .lhaarchive
A Japanese archive format released in 1988 by Haruyasu Yoshizaki. Ruled Japanese PC-98 and Windows 3.1 file distribution before ZIP took over. Rarely seen outside Japan; `.lha` and `.lzh` share the same bytes.
- .logtext
Runtime text output from apps and servers. The first place incident responders and admins look when something goes wrong.
- .m4aaudio
AAC or ALAC audio wrapped in an MP4 container. Born from iTunes and best supported inside the Apple ecosystem.
- .mdtext
Markdown source. A lightweight markup language used by GitHub READMEs, static site generators, and most technical blogs.
- .mhtweb
A single-file web page: HTML, images, and CSS bundled as a MIME multipart message. Born with Internet Explorer and still common in Chinese enterprise software and some government portals.
- .mkvvideo
An open container that can bundle multiple audio tracks, subtitle streams, and chapter metadata — popular for anime rips and archival recordings.
- .mobidocument
The early Amazon Kindle e-book format. Amazon has since moved on to AZW3 and KFX; MOBI is legacy.
- .movvideo
Apple's QuickTime container, widely produced by iPhone screen recordings and iMovie exports. Structurally similar to MP4, so conversions are usually lossless.
- .mp3audio
The de-facto standard for music distribution for over 25 years. Playable on virtually anything with a speaker.
- .mp4video
The MPEG-4 container format that bundles video, audio, and subtitles. It is the de-facto universal video format — iPhones, Android, YouTube, everywhere.
- .msiexecutable
The standard Windows installer container. Holds install, upgrade, repair, and uninstall instructions.
- .numbersdocument
The native format for Apple's Numbers spreadsheet. Each sheet is a freeform canvas hosting multiple tables and charts.
- .odpdocument
The ISO OpenDocument presentation format. Native to LibreOffice Impress and convertible to/from pptx.
- .odsdocument
The ISO OpenDocument spreadsheet format. Native to LibreOffice Calc and broadly interoperable with xlsx.
- .odtdocument
The ISO-standardised open document format. Native to LibreOffice and OpenOffice, and broadly interoperable with docx.
- .oggaudio
Xiph.Org's open media container. Hosts Vorbis (audio), Theora (video), or Opus (audio) streams — royalty-free and common in open-source pipelines.
- .otffont
The successor font format co-developed by Adobe and Microsoft. A TrueType superset that can carry CFF (PostScript) outlines.
- .pagesdocument
A document created by Apple's Pages word processor on macOS / iOS. Internally a ZIP bundle of XML and preview imagery.
- .pdfdocument
A fixed-layout document format used anywhere the exact look of a page matters — contracts, invoices, manuals, and printable forms. PDFs render the same way across OSes and printers.
- .phpcode
Server-side PHP source. Powers a huge slice of the web via WordPress, Laravel, and classic LAMP stacks.
- .pkgexecutable
The macOS Installer package. Used to ship apps that require system-level changes rather than a simple .app drag-to-Applications.
- .pngimage
A lossless raster image format with transparency (alpha channel). The default for logos, screenshots, and UI assets on the web.
- .pptdocument
PowerPoint's pre-2007 binary format. Still shared in government and large enterprises; macro-enabled variants need the usual caution.
- .pptxdocument
PowerPoint's format from 2007 onward. A ZIP bundle of XML and media that also opens cleanly in Keynote and LibreOffice Impress.
- .ps1executable
A PowerShell script. Used for Windows administration, server operations, and DevOps pipelines.
- .psdimage
Adobe Photoshop's native format. Preserves layers, masks, smart objects, and adjustment layers for ongoing edits.
- .pycode
Python source code. Ubiquitous in data analysis, ML, automation, and backends — runs on every mainstream OS.
- .rararchive
WinRAR's proprietary archive format. Higher compression ratios than ZIP and optional recovery records for repairing damaged splits.
- .rawimage
A camera RAW file containing untouched sensor data. Each vendor ships its own flavour — Canon .cr3, Nikon .nef, Sony .arw, etc.
- .rbcode
Source for Ruby, Yukihiro Matsumoto's dynamic scripting language. Rails brought it into the web-development mainstream.
- .rpmexecutable
Red Hat-family Linux package format (RHEL, CentOS, Fedora, openSUSE). Managed with dnf / yum / zypper.
- .rscode
Source for the Rust systems language — memory safety without a garbage collector, powering web backends, CLIs, and even kernels.
- .rtfdocument
Microsoft's cross-platform formatted-text format. Richer than plain text, and the lowest common denominator for formatted documents on every OS.
- .shexecutable
A script executed by a Unix shell (bash, zsh, sh). A shebang on line one picks the interpreter; the execute bit controls whether it can run.
- .sitarchive
Aladdin Systems' (now Smith Micro) 1987 archive format for classic Mac. The de-facto standard for Mac software distribution before OS X, and still occasionally encountered when digging through legacy Mac media.
- .sqlcode
A text file of SQL statements — queries, DDL, DML — used for backups, migrations, and ad-hoc analysis.
- .sqlitedata
A self-contained relational database in a single file. Embedded in iOS, Android, and browsers — the de-facto standard for mobile local storage.
- .svgimage
An XML-based vector image format. Logos, icons, and charts stay crisp at any size and can be styled with CSS or manipulated with JavaScript.
- .swiftcode
Source for Apple's modern Swift language. First-choice for iOS, macOS, watchOS, and tvOS apps.
- .tararchive
A Unix-born archive format. Plain tar is uncompressed and is commonly paired with gzip or xz to produce `.tar.gz` / `.tar.xz`.
- .tiffimage
The workhorse of print and scanning. Supports uncompressed, LZW, and JPEG-compressed payloads and can hold multiple pages per file.
- .tomldata
A configuration-focused data format with unambiguous syntax. Adopted by Rust's Cargo and Python packaging (pyproject.toml).
- .tscode
Microsoft's typed superset of JavaScript. The de-facto standard for serious front-end and Node.js projects.
- .ttffont
The TrueType font format originated at Apple and was standardised with Microsoft. Widely supported on Windows, macOS, and Linux.
- .txttext
The simplest possible text file, with no formatting. Works everywhere, and is the default for logs and quick notes.
- .wasmweb
A binary instruction format that runs near-native in browsers. Compiled from Rust / C / C++ for heavy computation or fast web apps.
- .wavaudio
The uncompressed audio container co-developed by Microsoft and IBM. A staple in music production and raw audio exchange.
- .webarchiveweb
The single-file web archive produced when Safari saves a page on macOS or iOS. Internally a binary plist bundling HTML, images, CSS, and JS.
- .webmvideo
A Google-led web video container built around VP8/VP9/AV1. Natively supported by HTML5 `<video>` in the major browsers.
- .webpimage
A modern web image format developed by Google. Produces smaller files than JPEG or PNG at equivalent quality, supports both lossy and lossless modes, and carries an alpha channel.
- .wmaaudio
Microsoft's proprietary audio codec. Paired with WMV, it was the default for Windows music services and voice recorders in the 2000s.
- .wmvvideo
Microsoft's video container, widespread in the 2000s and still found in legacy enterprise systems and lecture recordings.
- .wofffont
The first-generation web font format. A zlib-compressed TTF/OTF wrapper introduced around 2009. Largely superseded by WOFF2.
- .woff2font
A web-optimised font format. Takes TTF/OTF and adds Brotli compression — about 30% smaller than WOFF1.
- .xlsdocument
The pre-2007 binary Excel format. Still emitted by legacy enterprise systems and a classic malware delivery vector because of VBA macros.
- .xlsxdocument
Excel's default format since 2007. Under the hood, a ZIP bundle of XML and media — also readable by Numbers and LibreOffice Calc.
- .xmldata
A tag-based markup for structured data. Still everywhere — configs, RSS feeds, SOAP APIs, and Office Open XML packages.
- .xzarchive
LZMA2-based high-ratio compression. Common in Linux kernel and distribution tarballs, steadily displacing gzip.
- .yamldata
A human-friendly data format. Ubiquitous in CI/CD, Kubernetes, Docker Compose, and modern configuration files.
- .ziparchive
The most common archive format for bundling and compressing multiple files. Built into every major OS, widely used for email attachments and downloads.