Opera Mini

Opera Mini was derived from the Opera web browser for personal computers, which has been publicly available since 1996.[11] Opera Mini was originally intended for use on mobile phones not capable of running a conventional Web browser.[12] It was introduced on 10 August 2005, as a pilot project in cooperation with the Norwegian television station TV 2,[13] and only available to TV 2 customers. The beta version was made available in Sweden, Denmark, Norway, and Finland on 20 October 2005.[14] After the final version was launched in Germany on 10 November 2005,[15] and quietly released to all countries through the Opera Mini website in December, the browser was officially launched worldwide on 24 January 2006.[16] On 3 May 2006, Opera Mini 2.0 was released. It included new features such as the ability to download files, new custom skins, more search engine options on the built-in search bar, a speed dial option, new search engines, and improved navigation.[17] On 1 November 2006, Opera Mini 3 beta introduced secure browsing, RSS feeds, photo uploading and content folding.[18] Content folding works by folding long lists such as navigation bars into a single line that can be expanded as needed. A second beta was released on 22 November,[19] and on 28 November, the final version of Opera Mini 3 was released.[20]

On 7 November 2007, Opera Mini 4 was released. According to Johan Schön, technical lead of Opera Mini development, the entire code had been rewritten.[21] Opera Mini 4 includes the ability to view web pages similarly to a desktop based browser by introducing Overview and Zoom functions, and a landscape view setting. In Overview mode, the user can scroll a zoomed-out version of certain web pages.[22] Using a built-in pointer, the user can zoom into a portion of the page to provide a clearer view; this is similar to the functionality of Opera's Nintendo-based web browsers. This version also includes the ability to synchronise with Opera on a personal computer.[23][24] Prior to Opera Mini 4, the browser was offered in two editions: Opera Mini Advanced for high-memory MIDP 2 phones, and Opera Mini Basic for low-memory MIDP 1 phones.[25] Opera Mini 4 replaced Opera Mini Advanced.[26] Originally, Google was the default search engine on Opera Mini.[27] On 8 January 2007, Opera Software and Yahoo! announced a partnership to make Yahoo! search the default instead.[28] On 27 February 2008, Opera Software announced that Google would henceforth be the default search engine for Opera Mini and Opera Mobile. A version for the Android operating system was announced on 10 April 2008. Rather than port the code to Android, a wrapper was created to translate Java ME API calls to Android API calls.[29]

On 16 August 2009, Opera Software released Opera Mini 5.0 beta, which included tabbed browsing, a password manager, improved touch screen support, and a new interface, with a visual Speed Dial similar to the one introduced by Opera Software in their desktop browser.[30] The browser's use of compression and encrypted proxy-based technology to reduce traffic and speed page display has the side effect of allowing it to circumvent several approaches to Internet censorship. Since 20 November 2009, there have been reports from Chinese users that when they use Opera Mini, they are redirected to an error page leading them to download Opera Mini China version. This is almost certainly due to the Chinese government being concerned that users are using Opera Mini to bypass the Great Firewall of China. Opera agreed to route all of their traffic through government servers.[31][32] In 2009–10: A press release announcing that Indonesia's Smart Telecom had chosen Opera Mini for their devices said that Opera Mini was the world's most popular mobile browser, and that Russia and Indonesia were the largest users.[33] An iPhone version was approved for distribution by the Apple App Store on 13 April 2010.[34][35]

On 3 September 2014, Opera started taking registrations for the beta version of Opera Mini for Windows Phone.[36] The browser was released for Windows Phone on 9 September 2014, as a public beta,[37] the first Opera version for Microsoft's mobile platform since the discontinuation of Windows Mobile.

From 16 March 2015, Opera Mini's extreme compression mode uses an upgraded version of the Presto layout engine that is included in Opera 12.[46] Consequently, Opera Mini supports most of the web standards supported in Opera 12. Presto's development has continued for Opera Mini and further support was added for HTML5 input types, CSS Flexbox model, CSS rem units and ECMAScript 5.[46] However, unlike the desktop edition of Opera, frames are flattened because of client limitations, and dotted or dashed borders are displayed as solid borders due to bandwidth and memory issues.[47] As Opera Mini reformats web pages, it does not pass the Acid2 standards compliance test.[48][49] Opera Mini supports bi-directional text and can correctly display right-to-left scripts such as Arabic and Hebrew in addition to languages written left-to-right. However, it will not display right-to-left text if the font size is set to small or very small.[21] Indic and Chinese scripts are supported only if an appropriate font is installed on the device as the default system font.

For devices with screens 128 pixels wide or smaller, the default rendering mode is Small-Screen Rendering (SSR). In this mode, the page is reformatted into a single vertical column so that it only needs to be scrolled vertically.[22] Long lists and navigation bars are automatically collapsed (hiding most of the list or bar) by a feature known as "content folding". A plus (+) sign is displayed next to the collapsed content; when clicked, it toggles content folding.[50] Web developers can turn on SSR on the desktop edition of Opera to see how their websites will be displayed on mobile editions of Opera.[51] In SSR mode images are scaled down to no more than 70% of the screen size in either direction.[47]

Opera Mini can send content in bitmap image form if a font required is not available on the device, which is useful for indic scripts. Hindi, Bengali and a few other non-Latin character sets are supported.

When browsing the Web in Opera Mini mode, JavaScript is processed by the proxy server, and is merely rendered on the device. This limits interactivity. Scripts cannot be run in the background on the device. If a script is paused (on the server), the browser must communicate with the server to unpause it. JavaScript will only run for a couple of seconds on the Mini server before pausing, due to resource constraints.[52] On Opera Mini, before the page is sent to the mobile device, its onLoad events are fired and all scripts are allowed a maximum of two seconds to execute. The setInterval and setTimeout functions are disabled, so scripts designed to wait a certain amount of time before executing will not execute.[53] After the scripts have finished or the timeout is reached, all scripts are stopped and the page is compressed and sent to the mobile device. Once on the device, only a handful of events are allowed to trigger scripts:[53]

• onUnload: Fires when the user navigates away from a page[54]
• onSubmit: Fires when a form is submitted[54]
• onChange: Fires when the value of an input control is changed[54]
• onClick: Fires when an element is clicked[54]

When one of these events is triggered, it sends a request to the proxy server to process the event. The proxy server then executes the JavaScript and returns the revised page to the mobile device.[53] Pop-ups, if not blocked by the JavaScript restrictions, replace the web page being viewed.[55] Opera has published Web content authoring guidelines to assist authors.[52]

Opera Mini can run in Turbo and Uncompressed modes, in addition to Mini mode. In Turbo mode, the amount of data transferred is still much reduced by compression, but, unlike Mini mode, JavaScript is not intercepted by the server and works properly. Opera Mini can be configured to choose compression mode automatically.

Opera Mini encrypts the connection between the mobile device and the Opera proxy server for security. The encryption key is obtained on the first start by requesting random keys a certain number of times.[56] Opera Mini supports most advanced version of Transport Layer Security (TLS) protocol[57] it also supports modern secure ciphers such as AES-GCM and ECC. However, Opera Mini's Extreme mode does not offer true end-to-end security when visiting HTTPS encrypted websites only for data saving purpose.[58] With "Extreme/Mini mode" when visiting an encrypted web page, first the Opera Mini's servers decrypt the page, compress it for data saving then re-encrypt it themselves and finally forward it to the destination phone.[59] While browsing a secured site with "High/Turbo mode" or "Uncompressed mode" the connection is not intercepted by the Opera Mini server so that High and Uncompressed modes do not break end-to-end integrity.[60]

Opera Mini's address bar is capable of using several pre-configured search engines. The user can add more search engines.[61] The default search engines are Google and Wikipedia.

Opera Mini supports an ad blocker. When activated, Opera Mini servers try to filter out advertisement before rendering the page and sending it to the client phone.[63]

Opera Mini has an AI-powered news aggregator, serving personalised news,[64] night mode and private browsing. It can save bookmarks, download files, and web pages for offline reading. It supports streaming and remembers the user's browsing history.

If signed into an Opera Account, Saved Bookmarks, Speed Dials, Opened Tabs can be backed up and synchronized between different phones or with the Opera browser on computers, using the "Opera Sync" service, and can be accessed through web interface at Opera synchronization.

Total data consumed by Opera Mini users worldwide from 2006 to mid-2008 in TB

Opera Mini relies on data centers processing the Web page before sending it back to the phone in a compressed binary form. Opera Software operates data centers in the United States, Norway, China, Korea, Poland and Iceland.[66][67]

Several mobile network companies pre-install Opera Mini on their mobile phones, including Telenor, AT&T, Vodafone, T-Mobile, KDDI, Omnitel, Pannon GSM, Telefónica Móviles de España and TMN.

The following devices were supplied pre-installed with Opera Mini as of August 2007. Some listed devices only included Opera Mini when bought from certain network operators.[68]

• Motorola V980, E2, L7, i1[69]
• Nokia Nokia Asha series, 2610, 2700 classic, 2730 classic, 3110 classic, 3120 classic, 3500 classic, 3600, 3600 slide, 3710 fold, 3720 classic, 5000, 5070, 5130, 5230, 5310, 5500 Sport, 5610, 6080, 6085, 6103, 6131, 6233, 6288, 6300,[70] 6303 classic, 6600 slide, 7373, 8800 Arte, Nokia C2-01, Nokia C3, E65, N71, N73, N95, and 3310 (2017)
• HMD Nokia phones with a preinstalled browser and running s30+ all run on the Opera Mini Browser[71]
• Sony Ericsson K310i, K530i, K550, W200i, W205, W760i, W910i, Z530i, Z550i, Z780i
• Samsung X160, E570, E420, F480, X510, X650, E900, E250, U700, ZV60, D900i
• LG K880, KU250, KE970, and KU311
• SAGEM My411x and P9521
• BenQ-Siemens EL71 and EF81
• BenQ E71 fight
• Orange Rio (ZTE-G X991)

While not officially supported on ChromeOS, Vlad Filippov published a guide that teaches how to run Opera Mini inside the Chromium browser.[72]