| File extension | Developer/Producer | File description |
|---|---|---|
| 509 file extension | N/A | Internet Security Certificate |
| A4P file extension | Avanquest Software | A4Desk Pro Project Format |
| A5WCMP file extension | Alpha Software, Inc. | Alpha Five Web Publishing |
| ABD file extension | RITLabs SRL | The Bat! Mail Processing System |
| ADR file extension | N/A | Opera Bookmarks Format |
| AEX file extension | Alpha Software | Greetings Card Format |
| AGS file extension | BigProf software | AppGini Saved Style Sheet |
| AHTM file extension | N/A | HTML |
| ALX file extension | Microsoft | Internet Script Language Defines 2-D Layout ActiveX Layout Format |
| AN file extension | Adobe Systems | Adobe Edge Animate Project Format |
| AP file extension | Fifth Generation Systems | Fifth Generation Systems Active Page Format |
| AQF file extension | Liquid Development, LLP | Aquifer-Generated Web Page |
| ARGO file extension | Tigris.org | ArgoUML Project |
| ARO file extension | Tomahawk Technologies | SteelArrow Script Format |
| ASA file extension | N/A | Active Server Configuration Format |
| ASAX file extension | Microsoft | ASP.NET Application Optional Source Format |
| ASCX file extension | Microsoft | Active Server Pages Web User Control Format |
| ASHX file extension | Microsoft | ASP.NET Web Handler Format |
| ASIS file extension | Apache Software Foundation | Apache As Is |
| ASMX file extension | Microsoft | Active Server Plus Web Services Source Format |
| ASP file extension | Microsoft | Active Server Page Script Page |
| ASPX file extension | Microsoft | Active Server Page Extended ASP.NET Script Format |
| ASR file extension | Adobe Systems | Adobe Flash ActionScript Remote Format |
| ATA file extension | Julian Spencer | Antenna Project |
| ATOM file extension | N/A | Atom Web Feed Format |
| ATT file extension | N/A | Web Form Data Format |
| AWM file extension | Likno Software | Likno AllWebMenus Format |
| AXD file extension | Microsoft | ASP.NET Web Handler Format |
| AXL file extension | N/A | XML Project |
| BBE file extension | MindGenius Ltd. | MindGenius Brainbloom |
| BCX file extension | Systeam | Beam Report Standard Definition |
| BIKEY file extension | Bohemia Interactive | Bohemia Interactive Key |
| BIMD file extension | Automated Architecture, Inc. | Blue Ink Meta-data Export |
| BINARYCOOKIES file extension | Apple, Inc. | Safari Browser Cookies Package |
| BML file extension | N/A | Bean Markup Language Format |
| BOE file extension | Microsoft Corporation | Microsoft Outlook Express Backup |
| BOK file extension | eBay | ProStores Dynamic Web Format |
| BOOKEXPORT file extension | Blurb | Booksmart Export Format |
| BROWSER file extension | Microsoft | ASP.NET Browser Definition Format |
| BSON file extension | 10gen | BSON Binary JSON |
| BTAPP file extension | BitTorrent | UTorrent Application Format |
| BTT file extension | ICQ LLC | ICQ Find Users |
| BTX file extension | Inmagic, Inc. | InMagic Database Term/word Index |
| BWP file extension | Fluffy Smoke Entertainment | BuRg3r Web Page |
| CAPS file extension | GoldGingko Software | CaptureSaver |
| CDF file extension | N/A | Channel Definition Format |
| CER file extension | N/A | Internet Security Certificate |
| CERT file extension | AOL Inc. | Netscape Certificate Index |
| CFM file extension | Adobe Systems | Adobe ColdFusion Template Format |
| CFML file extension | Adobe Systems | Adobe ColdFusion Markup Language Format |
| CHA file extension | N/A | Online Chat Configuration Format |
| CHAT file extension | N/A | Online Chat Configuration Format |
| CHM file extension | Microsoft | Microsoft Compiled HTML Help Format |
| CHTML file extension | N/A | Compact HTML Document |
| CMS file extension | N/A | Content Management System Web Page Format |
| CODASITE file extension | Panic | Coda For Mac Web Project Format |
| COMPRESSED file extension | WordCompress | WordCompress Compacted Web Format |
| CON file extension | RadGs | Concept Application Server Source Code Format |
| COOK file extension | N/A | Netscape For Mac Cookie |
| CQL file extension | SiHiDa and balduz | XDCC Catcher Queue List |
| CRDOWNLOAD file extension | Google Chrome Incomplete Download Format | |
| CRL file extension | N/A | Certificate Revocation List |
| CRT file extension | N/A | Internet Security Certificate |
| CSCPKT file extension | Colasoft | Sample Packet |
| CSHTML file extension | Microsoft | ASP.Net Web Page |
| CSP file extension | RadGs | RadGs Concept Application Server Web Page Format |
| CSR file extension | N/A | Certificate Signing Request Format |
| CSS file extension | N/A | Cascading Style Sheets Format |
| CSS1 file extension | N/A | Cascading Style Sheet |
| DAP file extension | Microsoft | Microsoft Access Data Access Page Format |
| DBM file extension | Adobe Systems | Adobe ColdFusion Template Format |
| DBMG file extension | AOL Inc. | Netscale Navigator History |
| DBNX file extension | AOL Inc. | Netscape For Mac Host |
| DCR file extension | Adobe Systems | Adobe Director Shockwave Media Format |
| DER file extension | N/A | DER Encoded Internet Security Certificate Format |
| DHTML file extension | N/A | Dynamic HTML Format |
| DISCO file extension | Microsoft | DISCO Discovery Document |
| DISCOMAP file extension | Microsoft | Microsoft DISCO Discovery Output Format |
| DML file extension | Dynascript Technologies | DynaScript Markup Language Format |
| DO file extension | N/A | Java Servlet Format |
| DOCHTML file extension | Microsoft | Microsoft Word HTML Document Format |
| DOCMHTML file extension | Microsoft | Microsoft Word MIME HTML Document Format |
| DOTHTML file extension | Microsoft | Microsoft Word HTML Document Template Format |
| DOWNLOAD file extension | N/A | Chrome Partial Download Format |
| DWT file extension | Adobe Systems | Adobe Dreamweaver Template Format |
| ECE file extension | Escenic | Oracle Application Express Dynamic Web Page Format |
| ED2K file extension | eMule-Project.net | EDonkey Download Link |
| EDGE file extension | Adobe Systems | Adobe Edge Animation Project Format |
| EPA file extension | Picture Gear LLC. | EPhotoAlbum Album |
| ESPROJ file extension | MacRabbit | MacRabbit Espresso Project Format |
| EWP file extension | Ewisoft | ECommerce Website Builder Project Format |
| EZM file extension | E-PRESS Corp. | EasyOffice Mail |
| FCGI file extension | FastCGI | FastCGI Script Format |
| FEED-MS file extension | N/A | Microsoft Rss Feed Store |
| FEEDSDB-MS file extension | N/A | Microsoft RSS Feeds Store |
| FMP file extension | Dreamingsoft | 123 Flash Menu Project Format |
| FWEB file extension | IBM | Fortran WEB |
| FWP file extension | Microsoft | Frontpage Web Packages |
| GETRIGHT file extension | Headlight Software, Inc. | GetRight Unfinished Download |
| GMP file extension | Infacta Ltd. | Group Mail |
| GNE file extension | Ludicorp | Flickr PHP Format |
| GRX file extension | Headlight Software, Inc. | GetRight File List |
| GSCRIPT file extension | Google Inc. | Link To Google Scripts Web Application Script |
| GSP file extension | Ipswitch | IMail Server Returned Mail |
| HANDLEBARS file extension | N/A | Handlebars Template |
| HATHDL file extension | Hentai@Home Team | Hentai@Home Download |
| HDM file extension | Openwave | HDML Handheld Device Markup Language Format |
| HDML file extension | Openwave | Handheld Device Markup Language |
| HSQL file extension | N/A | HtmSQL Html |
| HTACCESS file extension | N/A | Apache Access Configuration Format |
| HTC file extension | Microsoft | HTML Component Format |
| HTD file extension | Adobe Systems Incorporated | Adobe ExtendScript HTML |
| HTM file extension | N/A | HTML Hypertext Markup Language Web Page Format |
| HTML file extension | N/A | HTML Hypertext Markup Language Web Page Format |
| HTML5 file extension | N/A | HTML5 Hypertext Markup Language Revision 5 Source |
| HTMS file extension | The PHP Group | PHP HTML Document |
| HTX file extension | Microsoft | Microsoft FrontPage Database Results |
| HXS file extension | Microsoft | Microsoft Help Compiled Storage Format |
| HYPE file extension | Tumult | Hype Web Project Format |
| IDC file extension | Microsoft | Internet Database Connector Document Format |
| IE3 file extension | Microsoft Corporation | Internet Explorer 3 |
| IHTML file extension | N/A | Inline HyperText Markup Language |
| ILHT file extension | Apple, Inc. | Safari Internet Location |
| IMAP file extension | Icewarp Ltd. | Merak Mail Server Internet Message Access Protocol |
| IMH file extension | Perion Network Ltd. | IncrediMail Contacts Export |
| IMPORTED file extension | BitTorrent, Inc. | UTorrent Torrent |
| IQY file extension | Microsoft | Microsoft Excel Internet Query Format |
| ITMS file extension | Apple | Apple ITunes Store URL Format |
| ITPC file extension | Apple | Apple ITunes Podcast Subscription Format |
| IVP file extension | Oracle Corporation | Panorama |
| IWDGT file extension | Apple | Apple IWeb Widget Format |
| IZS file extension | Evrsoft | 1st Page 2000 JavaScript Example |
| J2SI file extension | Epic Games, Inc. | Jazz Jackrabbit 2 Internet Server Link |
| JCCFG3 file extension | Trend Media Corporation Limited | FlashGet Incomplete Download |
| JCD file extension | Trend Media Corporation Limited | FlashGet Saved |
| JCZ file extension | Microsoft | Microsoft Liquid Motion Animation Format |
| JHTML file extension | N/A | ATG Dynamo Server Page (Java HTML) |
| JNLP file extension | N/A | Java Network Launching Protocol Format |
| JS file extension | N/A | JavaScript Format |
| JSP file extension | Oracle | JAVA Server Page Format |
| JSPA file extension | N/A | Java Servlet Alias Format |
| JSPX file extension | N/A | XML Java Server Page |
| JSS file extension | JSS | JAWS Script Source Format |
| JST file extension | Oracle | Java Server Page |
| JWS file extension | BEA Systems | Oracle WebLogic Server Java Web Services Format |
| LASSO file extension | LassoSoft | Lasso Database Driven Web Page |
| LAVS file extension | N/A | Liquid Audio Secured Download |
| LBC file extension | Curry K. Software | Cloaked Affiliate Link Builder Saved Link Format |
| LDI file extension | N/A | LDIF Address Book Interchange Format |
| LDMT file extension | Likno Software Inc. | Likno Drop-Down Menu Trees |
| LESS file extension | Alexis Sellier | LESS Style Sheet Format |
| LWAC file extension | Likno Software Inc. | Likno Web Accordion Builder |
| LWBM file extension | Likno Software Inc. | Likno Web Button Maker |
| LWTT file extension | Likno Software Inc. | Likno Web Tooltips Builder |
| MAFF file extension | Mozilla | Mozilla Archive Format |
| MAILDB file extension | N/A | MSN Mail |
| MAILSTATIONERY file extension | Apple, Inc. | Apple Mail |
| MAP file extension | N/A | Server Side Image Map Format |
| MAPX file extension | Mapjects Development | Mapjects GRYD Webserver Format |
| MASTER file extension | Microsoft | ASP Master Page Format |
| META4 file extension | N/A | Metalink 4.0 |
| METALINK file extension | N/A | Metalink 3.0 |
| MHT file extension | N/A | Mime HTML (MHTML) Format |
| MHTM file extension | N/A | Mime HTML (MHTML) |
| MHTML file extension | N/A | Mime MHTML Format |
| MIB file extension | N/A | Management Information Base |
| MLM file extension | Novell, Inc. | Novell GroupWise Saved Email Message |
| MMDF file extension | N/A | Multi-channel Memorandum Distribution Facility Mailbox Format |
| MOSS file extension | AOL Inc. | Netscape Navigator For Mac HTML |
| MOZ file extension | N/A | Netscape Temporary Cache Format |
| MOZEML file extension | Mozilla Corporation | Mozilla Thunderbird Mail Message |
| MSIE file extension | N/A | Microsoft Internet Explorer For Mac HTML |
| MSPX file extension | Microsoft | Microsoft XML-based Web Page |
| MTML file extension | N/A | Meaningful Text Markup Language |
| MUSE file extension | Adobe Systems | Adobe Muse Project Format |
| MVC file extension | Miva Merchant | Sony Digital Mavica Photo Image Format |
| MVR file extension | IBM | IBM HotMedia Multimedia Format |
| MWE file extension | Oracle Corporation | OpenArchitectureWare Workflow |
| MXDL file extension | Maxthon International Limited | Maxthon Incomplete Download |
| NEWSLOC file extension | Apple, Inc. | Apple Mac OS X Finder News Internet Location |
| NOD file extension | NetObjects | NetObjects Fusion Nodes Format |
| NOF file extension | NetObjects Inc. | NetObject Fusion 5.0 |
| NXG file extension | Netopia | ESite Builder NXG Web Page Format |
| NZB file extension | NewzBin.com | Newzbin Download Pointer Format |
| OAM file extension | Adobe Systems | Adobe Edge Overlay Format |
| OBML file extension | Opera Software | Opera Mini Saved Web Page Format |
| OBML15 file extension | Opera Software ASA | Opera Mini 5.1 Saved Web Page |
| OGNC file extension | N/A | Dynamic Web Page Format |
| OPML file extension | N/A | OPML Outline Processor Markup Language File Format |
| OTH file extension | N/A | OpenOffice.org OpenDocument HTML Text Template |
| OUTLOOK97 file extension | Microsoft Corporation | Microsoft Outlook Custom Mail |
| P12 file extension | N/A | PFX File (Personal Information Exchange) |
| P7 file extension | N/A | PKCS #7 Digital Certificate Format |
| P7C file extension | N/A | PKCS #7 Certificate Format |
| PAC file extension | Netscape | Proxy Automatic Configuration Format |
| PAG file extension | LMSoft | Lmsoft Hypermedia Page |
| PAGE file extension | HybridServerPages Group | HybridJava Web Page Format |
| PBX file extension | Microsoft Corporation | Outlook Express Message Folder |
| PEM file extension | N/A | Privacy Enhanced Mail Security Certificate Format |
| PHP file extension | N/A | PHP Script Or Page |
| PHP3 file extension | N/A | PHP Version 3 Script Format |
| PHP4 file extension | N/A | HTML Page With PHP (HyperText PreProcessor) |
| PHP5 file extension | N/A | PHP Script Version 5 (HyperText PreProcessor) |
| PHT file extension | N/A | Partial Hypertext |
| PHTM file extension | N/A | PHP Web Page Format |
| PHTML file extension | N/A | PHP Web Page |
| PIH file extension | N/A | Karrigell Python HTML |
| PM1 file extension | David Harris | Pegasus Mail Secondary Address Book Index |
| PMI file extension | David Harris | Pegasus Mail Message Folder Index |
| PMX file extension | David Harris | Pegasus Mail Outgoing Message |
| PPTHTML file extension | Microsoft | Microsoft PowerPoint HTML Presentation Format |
| PPTMHTML file extension | Microsoft | Microsoft PowerPoint MIME HTML Presentation Format |
| PRF file extension | W3C | PICS Rules Format |
| PSP file extension | Oracle | PL/SQL Server Page Format |
| PTW file extension | Autodesk | AutoCAD Publish To Web Settings Format |
| PUB file extension | N/A | PGP Public Key Format |
| PUBKR file extension | PGP Corporation | Pretty Good Privacy Public Key Ring Data |
| QBO file extension | Intuit | QuickBooks Online Bank Statement Format |
| QF file extension | Qompose | Qompose HTML Template Format |
| QQQ file extension | TotalFix team | TotalFix Fixed AVI |
| QRM file extension | Qworum | Qworum Message Format |
| RHTML file extension | N/A | Ruby HTML Web Page Format |
| RJS file extension | N/A | Ruby JavaScript Source Code Format |
| RNK file extension | Microsoft Corporation | Dial-up Shortcut |
| RSS file extension | N/A | Really Simple Syndication - RSS File Format |
| RW3 file extension | Realmac Software | RapidWeaver Site Design Format |
| RWP file extension | Realmac Software | RapidWeaver Web Package Format |
| RWSW file extension | Realmac Software | RapidWeaver Website Saved Project |
| RWTHEME file extension | Realmac Software | RapidWeaver Theme Format |
| SAVEDDECK file extension | Nokia | Nokia Saved Web Page Format |
| SDB file extension | SocialDecks | SocialDecks Blog Format |
| SEAM file extension | JBoss | Seam Framework Java Servlet Format |
| SECUREDOWNLOAD file extension | Apple, Inc. | Safari Download |
| SEX file extension | Alpha Software, Inc. | Alpha Five Set Index |
| SHT file extension | N/A | HTML Server Side Include Format |
| SHTM file extension | N/A | HTML Server Side Include Format |
| SHTML file extension | N/A | HTML Server Side Include Format |
| SITE file extension | Adobe Systems | Adobe GoLive Site Specific Format |
| SITEMAP file extension | Microsoft | ASP .NET Site Map |
| SITES file extension | Apple | Apple IWeb Domain Format |
| SITES2 file extension | Apple | Apple IWeb Domain Format |
| SPC file extension | N/A | PKCS #7 Certificate Format |
| SPDESIGNOPEN file extension | Microsoft Corporation | SharePoint Designer |
| SPDESIGNSITEMAP file extension | Microsoft Corporation | SharePoint Designer Site Map |
| SRF file extension | Microsoft | Microsoft Visual Studio Server Response Format |
| SRX file extension | N/A | SPARQL Query Results XML Format Result |
| SSAGE file extension | Microsoft Corporation | Inbound Internet Email Message |
| SSH file extension | Microsoft Corporation | Microsoft Internet Explorer Style Sheet |
| SSP file extension | Scalate | Scala Server Page |
| STL file extension | Microsoft | Certificate Trust List |
| STM file extension | N/A | HTML Server Side Include Format |
| STML file extension | N/A | HTML Server Side Include Format |
| STP file extension | Microsoft | Microsoft SharePoint Services Template |
| SUCK file extension | SiteSucker | SiteSucker Website Format |
| SVC file extension | Microsoft | Microsoft Visual Studio ASP.NET WCF Web Service Format |
| SVR file extension | N/A | Compressed Virtual World |
| SWF2 file extension | Adobe Systems Incorporated | Flash |
| SWFL file extension | Adobe Systems Incorporated | Shockwave Flash |
| SWZ file extension | Adobe Systems | Adobe Flash Player Signed RSL Format |
| TBB file extension | RITLabs SRL | The Bat! E-mail Hives |
| TNF file extension | Microsoft Corporation | Transport Neutral Encapsulation Format |
| TVPI file extension | Decisionmark | TitanTV Television Listing Format |
| TVVI file extension | Decisionmark | TitanTV Television Listing Format |
| UCF file extension | Cisco Systems | WebEx Universal Communications Format |
| UHTML file extension | UC Mobile | UC Browser Saved Webpage |
| UPL file extension | Star Finanz GmbH | StarMoney Agent Download |
| URL file extension | N/A | Internet Shortcut - URL - Uniform Resource Locator |
| URLS file extension | Headlight Software, Inc. | GetRight Internet Shortcuts List |
| URL_ file extension | N/A | Internet Shortcut - URL - Uniform Resource Locator |
| VBD file extension | Microsoft | Microsoft Visual Basic ActiveX Document Format |
| VBHTML file extension | Microsoft | ASP.NET Razor Web Page |
| VDW file extension | Microsoft | Microsoft Visio Web Drawing Format |
| VLP file extension | Valadeo | LiveSite Project |
| VNU file extension | CoffeeCup Software, Inc. | CoffeeCup Visual Site Designer Project |
| VRGE08CONTACT file extension | Microsoft Corporation | Microsoft Entourage 2008 Contact |
| VRGE08EVENT file extension | Microsoft Corporation | Microsoft Entourage 2008 Event |
| VRGE08GROUP file extension | Microsoft Corporation | Microsoft Entourage 2008 Group |
| VRGE08MESSAGE file extension | Microsoft Corporation | Microsoft Entourage 2008 Message |
| VRGE08NOTE file extension | Microsoft Corporation | Microsoft Entourage 2008 Note |
| VRML file extension | N/A | Virtual Reality Modeling Language Format |
| VSDISCO file extension | Microsoft | DISCO Dynamic Discovery Document |
| WBS file extension | MicroVision Development, Inc. | WebExpress Website |
| WBXML file extension | Open Mobile Alliance | WAP Binary XML Format |
| WDGT file extension | N/A | Opera Browser Widget |
| WEBARCHIVE file extension | Apple | Apple Safari Web Archive Format |
| WEBARCHIVEXML file extension | Android 3.1 Browser Saved Website Format | |
| WEBBOOKMARK file extension | Apple | Apple Safari Bookmark Format |
| WEBHISTORY file extension | Apple | Apple Safari History Item Format |
| WEBINTENTS file extension | N/A | Webintents |
| WEBLOC file extension | Apple | Apple Mac OS X Finder Internet URL |
| WEBPUBLISHHISTORY file extension | Alpha Software, Inc. | Alpha Five |
| WEBSITE file extension | Microsoft | Internet Explorer 9 Pinned Site Shortcut Format |
| WEBTEST file extension | Microsoft Corporation | Microsoft Visual Studio Web Test |
| WGP file extension | WebHat | Web Gallery Project Format |
| WGT file extension | Opera Software | Opera Widgets Format |
| WHTT file extension | Xavier Roche | WinHTTrack Project |
| WIDGET file extension | HybridServerPages Group | HybridJava Widget Format |
| WML file extension | N/A | Wireless Markup Language Document (WAP) |
| WOA file extension | Apple | WebObjects Script Format |
| WPP file extension | Serif | Serif WebPlus Format |
| WRF file extension | Cisco Systems | WebEx Recording Format |
| WSDL file extension | Microsoft | Microsoft Visual Studio Web Service Description Language Format |
| WTK file extension | Institute for Geotechnical Engineering IGT | WinTalk URL Address |
| WWT file extension | PC SOFT | WinDev Page Template |
| XBEL file extension | Python XML SIG | XBEL Bookmarks Format |
| XBL file extension | Mozilla | Extensible Binding Language Format |
| XFDL file extension | UWI | XFDL Format |
| XHTM file extension | N/A | Extensible HTML Format |
| XHTML file extension | N/A | Extensible HTML Format |
| XSS file extension | Oracle | XML Style Sheet |
| XTML file extension | Altairis, s. r. o. | XML4web Virtual HTML Document |
| XUL file extension | Mozilla | Firefox XML User Interface Language Format |
| XWS file extension | MAGIX | Xara Webstyle Format |
| YAWS file extension | N/A | Yaws Source |
| ZBD file extension | N/A | Zebedee Encrypted |
| ZED file extension | BitTorrent, Inc. | BitTorrent Metainfo |
| ZFO file extension | N/A | XSL-FO Online Form |
| ZHTML file extension | Winferno Software | Secure IE Zipped HTML Format |
| ZUL file extension | Potix | ZK User Interface Format |
| ZVZ file extension | N/A | Malware Format |
Web Developer acting on his own, author of Internet solutions facilitating working with new technologies for less advanced users. Internet maniac.
