||This article's Criticism or Controversy section may compromise the article's neutral point of view of the subject. (April 2017)|
|Initial release||January 2009|
|Type||Instant messaging and social media|
|Type of business||Subsidiary|
|Founded||February 24, 2009|
|Headquarters||Mountain View, California, United States|
WhatsApp Messenger is a freeware, cross-platform and end-to-end encrypted instant messaging application for smartphones. It uses the Internet to make voice calls, one to one video calls; send text messages, images, GIF, videos, documents, user location, audio files, phone contacts and voice notes to other users using standard cellular mobile numbers. It also incorporates a feature called Status, which allows users to upload photos and videos to a 24-hours-lifetime feed that, by default, are visible to all contacts; similar to Snapchat, Facebook and Instagram Stories.
WhatsApp Inc., based in Mountain View, California, was acquired by Facebook in February 2014 for approximately US$19.3 billion. By February 2016, WhatsApp had a user base of over one billion, making it the most popular messaging application at the time.
WhatsApp, was incorporated in 2009 by Brian Acton and Jan Koum, both former employees of Yahoo!. After Koum and Acton left Yahoo! in September 2007, the duo traveled to South America as a break from work. At one point they applied for jobs at Facebook but were rejected. For the rest of the following years Koum relied on his $400,000 savings from Yahoo!. In January 2009, after purchasing an iPhone and realizing that the App Store would soon create an industry of apps, Koum started visiting his friend Alex Fishman in West San Jose where the three would discuss "... having statuses next to individual names of the people", but this was not possible without an iPhone developer. Fishman found a Russian developer on RentACoder.com, Igor Solomennikov, and introduced him to Koum. Koum named the app "WhatsApp" to sound like "what's up". On February 24, 2009, he incorporated WhatsApp Inc. in California. However, because early versions of WhatsApp often crashed or got stuck at a particular point, Koum felt like giving up and looking for a new job, upon which Acton encouraged him to wait for a "few more months".
In June 2009, Apple launched push notifications, allowing users to be pinged when they were not using an app. Koum changed WhatsApp so that when a user's status is changed, everyone in the user's network would be notified. WhatsApp 2.0 was released with a messaging component and the number of active users suddenly increased to 250,000. Acton was still unemployed and managing another startup, and he decided to join the company. In October 2009, Acton persuaded five former friends in Yahoo! to invest $250,000 in seed funding, and Acton became a co-founder and was given a stake. He officially joined on November 1. After months at beta stage, the application eventually launched in November 2009 exclusively on the App Store for the iPhone. Koum then hired a friend who lived in Los Angeles, Chris Peiffer, to develop the BlackBerry version, which arrived two months later.
WhatsApp was switched from a free to paid service to avoid growing too fast, mainly because the primary cost was sending verification texts to users. In December 2009, the ability to send photos was added to WhatsApp for the iPhone. By early 2011, WhatsApp was one of the top 20 apps in Apple's U.S. App Store.
In April 2011, Sequoia Capital was the only venture investor in WhatsApp and paid approximately $8 million for more than 15 percent of the company, after months of negotiation with Sequoia partner Jim Goetz.
By February 2013, WhatsApp had about 200 million active users and 50 staff members. Sequoia invested another $50 million, and WhatsApp was valued at $1.5 billion.
In a December 2013 blog post, WhatsApp claimed that 400 million active users use the service each month. As of April 22, 2014, WhatsApp had over 500 million monthly active users, 700 million photos and 100 million videos were being shared daily, and the messaging system was handling more than 10 billion messages each day. On August 24, 2014, Koum announced on his Twitter account that WhatsApp had over 600 million active users worldwide. At that point WhatsApp was adding about 25 million new users every month, or 833,000 active users per day. With 65 million active users representing 10% of the total worldwide users, India has the largest number of consumers.
Facebook acquisition (2014–2015)
On February 19, 2014, months after a venture capital financing round at a $1.5 billion valuation, Facebook announced it was acquiring WhatsApp for US$19 billion, its largest acquisition to date. At the time, the acquisition was the largest purchase of a venture-backed company in history. Sequoia Capital received an approximate 50x return on its initial investment. Facebook, which was advised by Allen & Co, paid $4 billion in cash, $12 billion in Facebook shares, and an additional $3 billion in restricted stock units granted to WhatsApp's founders (advised by Morgan Stanley), Koum and Acton. Employee stock was scheduled to vest over four years subsequent to closing. The transaction was the largest purchase of a company backed by venture capitalists to date. Days after the announcement, WhatsApp users experienced a loss of service, leading to anger across social media.
The acquisition caused a considerable number of users to move, or try out other message services as well. Telegram claimed to have seen 8 million additional downloads of its app. Line claimed to have seen 2 million new users for its service.
At a keynote presentation at the Mobile World Congress in Barcelona in February 2014, Facebook CEO Mark Zuckerberg said that Facebook's acquisition of WhatsApp was closely related to the Internet.org vision. According to a TechCrunch article, Zuckerberg's vision for Internet.org was as follows: "The idea, he said, is to develop a group of basic internet services that would be free of charge to use – 'a 911 for the internet.' These could be a social networking service like Facebook, a messaging service, maybe search and other things like weather. Providing a bundle of these free of charge to users will work like a gateway drug of sorts – users who may be able to afford data services and phones these days just don’t see the point of why they would pay for those data services. This would give them some context for why they are important, and that will lead them to paying for more services like this – or so the hope goes."
On May 9, 2014, the government of Iran announced that it had proposed to block the access to WhatsApp service to Iranian residents. "The reason for this is the assumption of WhatsApp by the Facebook founder Mark Zuckerberg, who is an American Zionist," said Abdolsamad Khorramabadi, head of the country's Committee on Internet Crimes. Subsequently Iranian president Hassan Rouhani issued an order to the Ministry of ICT to stop filtering WhatsApp.
Just three days after announcing that WhatsApp had been purchased by Facebook, Koum said they were working to introduce voice calls in the coming months. He also advanced that new mobile phones would be sold in Germany with the WhatsApp brand, as their main goal was to be in all smartphones.
In August 2014, WhatsApp was the most globally popular messaging app, with more than 600 million active users. By early January 2015, WhatsApp had 700 million monthly active users with over 30 billion messages being sent every day. In April 2015, Forbes predicted that between 2012 and 2018, the telecommunications industry will lose a combined total of $386 billion because of OTT services like WhatsApp and Skype. That month, WhatsApp had over 800 million active users. By September 2015, the user base had grown to 900 million, and by February 2016 it had grown to one billion.
As of November 30, 2015, the Android client for WhatsApp started making links to another messenger called Telegram unclickable and uncopyable. This is an active block, as confirmed by multiple sources, rather than a bug, and the Android source code which recognises Telegram URLs has been identified. URLs with "telegram" as domain-name are targeted actively and explicitly – the word "telegram" appears in the code. This functioning risks being considered anti-competitive, and has not been explained by WhatsApp.
On January 18, 2016, WhatsApp's founder Jan Koum announced that the service would no longer charge their users a $1 annual subscription fee in an effort to remove a barrier faced by some users who do not have a credit card to pay for the service. He also explained that the app would not display any third party advertisement and instead would bring new features such as the ability to communicate with business organizations.
By June 2016, more than 100 million voice calls are made per day on WhatsApp according to a post on the company's blog.
On November 10 2016, WhatsApp has started rolling out two-step verification feature for users on Android beta. This feature will add more security to your account, officials said. After enabling this feature, users will also get an option to add their email address for further protection. Also in November 2016, Facebook ceased collecting WhatsApp data for advertising in Europe.
On February 24 2017, (WhatsApp's 8th birthday) WhatsApp launches new Status feature that offering similar to Snapchat.
On May 18, 2017, it was reported that the European Commission was fining Facebook €110 million for "misleading" it during the 2014 takeover of WhatsApp. The commissioned alleges that in 2014, when it acquired the messaging app, it "falsely claimed it was technically impossible to automatically combine user information from Facebook and WhatsApp." However, in the summer of 2016 WhatsApp had begun sharing user information with its parent company, allowing information such as phone numbers to be used for targeted Facebook advertisements. Facebook acknowledged the breach, but said the errors in their 2014 filings were "not intentional."
After months at beta stage, the application eventually launched in November 2009 exclusively on the App Store for the iPhone. In January 2010, support for BlackBerry smartphones was added, and subsequently for Symbian OS in May 2010 and for Android OS in August 2010. In August 2011 a beta for Nokia's non-smartphone OS Series 40 was added. A month later support for Windows Phone was added, followed by BlackBerry 10 in March 2013. In April 2015, support for Samsung's Tizen OS was added. An unofficial port has been released for the MeeGo-based Nokia N9 called Wazapp, as well as a port for the Maemo-based Nokia N900 called Yappari.
The oldest device capable of running WhatsApp is the Symbian-based Nokia N95 released in March 2007.
In 2014 an unofficial open source plug-in called whatsapp-purple was released for Pidgin, implementing its XMPP and making it possible to use WhatsApp on a Windows or Linux PC.[third-party source needed] WhatsApp responded by automatically blocking phone numbers that connected to WhatsApp using this plug-in.
On January 21, 2015, WhatsApp launched WhatsApp Web, a web client which can be used through a web browser by syncing with the mobile device's connection.
On February 26, 2016, WhatsApp announced they would cease support for BlackBerry (including BlackBerry 10), Series 40 and Symbian, as well as some older versions of Android, Windows Phone and iOS, by the end of 2016. This has since been extended to June 30, 2017. 
WhatsApp was officially made available for PCs through a web client, under the name WhatsApp Web, in late January 2015 through an announcement made by Koum on his Facebook page: "Our web client is simply an extension of your phone: the web browser mirrors conversations and messages from your mobile device—this means all of your messages still live on your phone". The WhatsApp user's handset must still be connected to the Internet for the browser application to function. All major desktop browsers are supported except for Microsoft Internet Explorer. WhatsApp Web's user interface is based on the default Android one.
As of January 21, 2015, the desktop version was only available to Android, BlackBerry and Windows Phone users. Later on, it also added support for iOS, Nokia Series 40, and Nokia S60 (Symbian).
An unofficial derivative called WhatsAppTime has been developed, which is a standard Win32 application for PCs and supports notifications through the Windows notification area. There are similar solutions for macOS, such as the open-source ChitChat and multiple wrappers available in the App Store.
Windows and Mac
On May 10, 2016, the messaging service was introduced for both Windows and macOS operating systems. Similar to the WhatsApp Web format, the app, which will be synced with a user's mobile device, is available for download on the website. It supports OS versions of Windows 8 and OS X 10.9 and higher.
WhatsApp uses a customized version of the open standard Extensible Messaging and Presence Protocol (XMPP). Upon installation, it creates a user account using one's phone number as the username (Jabber ID:
WhatsApp software automatically compares all the phone numbers from the device's address book with its central database of WhatsApp users to automatically add contacts to the user's WhatsApp contact list. Previously the Android and Nokia Series 40 versions used an MD5-hashed, reversed-version of the phone's IMEI as password, while the iOS version used the phone's Wi-Fi MAC address instead of IMEI. A 2012 update now generates a random password on the server side.
In January 2015, WhatsApp introduced a voice calling feature; this helped WhatsApp to attract a completely different segment of the user population. On November 14, 2016, Whatsapp added video calling feature for users across Android, iPhone, and Windows Phone devices.
WhatsApp follows a "store and forward" mechanism for exchanging messages between two users. When a user sends a message, it first travels to the WhatsApp server where it is stored. Then the server repeatedly requests the receiver acknowledge receipt of the message. As soon as the message is acknowledged, the server drops the message; it is no longer available in database of server. WhatsApp server keeps the message only for 30 days in its database when it is not delivered (when the receiver is not active on WhatsApp for 30 days).[self-published source?]
On November 18, 2014, Open Whisper Systems announced a partnership with WhatsApp to provide end-to-end encryption by incorporating the encryption protocol used in Signal into each WhatsApp client platform. Open Whisper Systems said that they had already incorporated the protocol into the latest WhatsApp client for Android, and that support for other clients, group/media messages, and key verification would be coming soon after. WhatsApp confirmed the partnership to reporters, but there was no announcement or documentation about the encryption feature on the official website, and further requests for comment were declined. In April 2015, German magazine Heise Security used ARP spoofing to confirm that the protocol had been implemented for Android-to-Android messages, and that WhatsApp messages from or to iPhones running iOS were still not end-to-end encrypted. They expressed the concern that regular WhatsApp users still could not tell the difference between end-to-end encrypted messages and regular messages. On April 5, 2016, WhatsApp and Open Whisper Systems announced that they had finished adding end-to-end encryption to "every form of communication" on WhatsApp, and that users could now verify each other's keys. Users were also given the option to enable a trust on first use mechanism in order to be notified if a correspondent's key changes. According to a white paper that was released along with the announcement, WhatsApp messages are encrypted with the Signal Protocol. WhatsApp calls are encrypted with SRTP, and all client-server communications are "layered within a separate encrypted channel". The Signal Protocol library used by WhatsApp is open-source and published under the GPLv3 license.
On May 20, 2011, an unconfirmed security researcher from the Netherlands under the pseudonym "WhatsappHack" published, to the Dutch websites Tweakers.net and GeenStijl, a method by which WhatsApp accounts could be hijacked. The researcher noticed a flaw in the authentication process, which allowed the researcher to hijack an account by trying to login with another phone number and intercepting the verification SMS text message that, under specific conditions, remained in the outbox of the Symbian phone after the WhatsApp client would attempt to send it to itself. On Android, the verification message could be obtained through reading the "radio" with a tool named "logcat". The researcher would then copy and send the intercepted verification message to the real number of the phone, using an SMS gateway to spoof the "sender" phone number to the number the researcher tried to maliciously login with. This method worked, and WhatsApp issued a patch within one day after publication of the articles, to both the Android and Symbian clients. WhatsApp did have a security mechanism, by design, which would disable the account on the phone of the original owner of the phone number, when they had a WhatsApp account.
In May 2011, another security hole was reported which left communication through WhatsApp susceptible to packet analysis. WhatsApp communications were not encrypted, and data was sent and received in plaintext, meaning messages could easily be read if packet traces were available.
In May 2012 security researchers noticed that new updates of WhatsApp no longer sent messages as plaintext, but the cryptographic method implemented was subsequently described as "broken". In August 2012 the WhatsApp support staff said that messages were encrypted in the "latest version" of the WhatsApp software for iOS and Android (but not BlackBerry, Windows Phone, and Symbian), without specifying the cryptographic method.
On January 6, 2012, an unknown hacker published a website that made it possible to change the status of an arbitrary WhatsApp user, as long as the phone number was known. To make it work, it only required a restart of the app. According to the hacker, it was only one of many security problems in WhatsApp. On January 9, WhatsApp reported that it had resolved the problem, although the only measure actually taken was to block the website's IP address. As a reaction, a Windows tool was made available for download providing the same functionality. This problem has since been resolved in the form of an IP address check on currently logged-in sessions.
German Tech site The H demonstrated how to use WhatsAPI to hijack any WhatsApp account on September 14, 2012. Shortly after, a legal threat to WhatsAPI's developers was alleged, characterized by The H as "an apparent reaction" to security reports, and WhatsAPI's source code was taken down for some days. The WhatsAPI team has since returned to active development.
On December 1, 2014, Indrajeet Bhuyan and Saurav Kar, both 17 years old, demonstrated the WhatsApp Message Handler Vulnerability, which allows anyone to remotely crash WhatsApp just by sending a specially crafted message of 2kb in size. To escape the problem, the user who receives the specially crafted message has to delete his/her whole conversation and start a fresh chat, because opening the message keeps on crashing WhatsApp unless the chat is deleted completely. In early 2015, after WhatsApp launched a web client that can be used from the browser, Bhuyan also found that it had two security issues that compromised user privacy: the WhatsApp Photo Privacy Bug and the WhatsApp Web Photo Sync Bug.
On March 2, 2016, WhatsApp introduced its document-sharing feature, initially allowing users to share PDF files with their contacts. However, WhatsApp's default state of automatically downloading attachments raised some concerns in the press about risk and security once support for document sharing expanded beyond PDF files.
On January 13, 2017, The Guardian newspaper reported that security researcher Tobias Boelter had found that WhatsApp's policy of forcing re-encryption of initially undelivered messages, without informing the recipient, constituted a serious loophole whereby WhatsApp could disclose, or be compelled to disclose, the content of these messages. WhatsApp and Open Whisper Systems officials disagreed with this assessment. A follow-up article by Boelter himself explains in greater detail what he considers to be the specific vulnerability.
In March 2017, U.K. Secretary of State Amber Rudd said encryption capabilities of messaging tools like WhatsApp are unacceptable, as news reported that Khalid Masood used the application several minutes before perpetrating the 2017 Westminster attack. Rudd publicly called for police and intelligence agencies to be given access to WhatsApp and other encrypted messaging services to prevent future terror attacks.
In April 2017, the perpetrator of the Stockholm attack reportedly used WhatsApp to exchange messages with an ISIS supporter shortly before and after the 2017 Stockholm attack. The messages involved discussing how to make an explosive device and a confession of the perpetration the attack.
A major privacy and security problem has been the subject of a joint Canadian-Dutch government investigation. The primary concern was that WhatsApp required users to upload their mobile phone's entire address book to WhatsApp servers so that WhatsApp could discover who, among the users' contacts, was available via WhatsApp. While this was a fast and convenient way to quickly find and connect the user with contacts who were also using WhatsApp, it meant that their address book was then mirrored on the WhatsApp servers, including contact information for contacts who were not using WhatsApp. This information, which consisted solely of phone numbers without any additional information such as the name of the contact, was stored in hashed, though not salted, form. Late 2015, the Dutch government released a press-statement claiming that WhatsApp had changed its hashing method, making it much harder to reverse, and thus now fully complies with all rules and regulations.
A user does not need to send a friend request to send messages to another user, due to the contact discovery mentioned above.
In November 2014, WhatsApp introduced a feature named Read Receipts which alerts senders when their messages are read by recipients. Within a week, WhatsApp introduced an update allowing users to disable this feature so that message recipients do not send acknowledgements.
In February 2015, a Dutch university student named Maikel Zweerink published an app that set out to prove that anyone could track a WhatsApp user's status and also keep an eye of their changing profile pictures, privacy settings or status messages regardless of their privacy settings.
Security and privacy
On March 31, 2013 the Saudi Arabian Communications and Information Technology Commission (CITC) issued a statement regarding possible measures against WhatsApp, among other applications, unless the service providers took serious steps to comply with monitoring and privacy regulations.[needs update]
In February 2014, the public authority for data privacy of the German state of Schleswig-Holstein advised against using WhatsApp, as the service lacked privacy protection such as end-to-end client side encryption technology. WhatsApp started implementing end-to-end encryption in late 2014 and finished in April 2016.
From April 5, 2016, end-to-end encryption for all users' communications, including file transfers and voice calls, is supported for users of the latest client, encryption being enabled by default. It uses Curve25519 for key exchange, HKDF for generation of session keys (AES-256 in CBC mode for encryption and HMAC-SHA256 for integrity verification) and SHA512 for generating the two 30 digit finger prints of both users' identity keys so they can verify each other as needed. Even the company would be unable to decrypt users' communications. Amnesty International and security professionals praised the move; the US Federal Bureau of Investigation criticised it as threatening the work of law enforcement. Telegram, another messaging service, is reported by the BBC to be used by "Islamic State" extremists.
WhatsApp is not the only messaging service that provides end-to-end encryption; among others, Threema, Wickr, Signal, Silent Phone, and Line also provide such encryption by default. iMessage and Viber provide it under special circumstances. Telegram provides end-to-end encryption as an opt-in feature, but does not support end-to-end encrypted group messaging.
As of April 5, 2016[update], WhatsApp has a score of 6 out of 7 points on the Electronic Frontier Foundation's "Secure Messaging Scorecard". It has received points for having communications encrypted in transit, having communications encrypted with keys the provider doesn't have access to, allowing users to verify contacts' identities, having past messages secure if the encryption keys are stolen, having completed a recent independent security audit, and having the security designs properly documented. It is missing a point because the code is not open to independent review.
Brazilian court orders
On December 17, 2015, mobile providers in Brazil were ordered to block WhatsApp for 48 hours. The ban was ordered for the service's failure to cooperate with criminal court orders in July and August 2015. The following morning, however, a judge from the appeals court ordered that the ban be lifted for being an unreasonable response, recommending that the company be fined instead. Following the ban, but prior to its reversal, Facebook CEO Mark Zuckerberg responded by stating that he was "stunned that our efforts to protect people's data would result in such an extreme decision by a single judge to punish every person in Brazil who uses WhatsApp. We hope the Brazilian courts quickly reverse course." The competing service Telegram reported that 1.5 million Brazilians had downloaded its app while the WhatsApp ban was in place.
On March 1, 2016, Diego Dzodan, Facebook's vice-president for Latin America was arrested in Brazil for not cooperating with an investigation in which WhatsApp conversations were requested. On March 2, 2016, at dawn the next day, Dzodan was released because the Court of Appeal held that the arrest was disproportionate and unreasonable.
On May 2, 2016, mobile providers in Brazil were ordered to block WhatsApp for 72 hours for the service's second failure to cooperate with criminal court orders. Once again, the block was lifted following an appeal, after nearly 24 hours.
In response to the Facebook acquisition in 2014, Slate columnist Matthew Yglesias questioned whether the company's business model of charging users $1 a year was viable in the United States in the long term. It had prospered by exploiting a "loophole" in mobile phone carriers' pricing. "Mobile phone operators aren't really selling consumers some voice service, some data service, and some SMS service", he explained. "They are selling access to the network. The different pricing schemes they come up with are just different ways of trying to maximize the value they extract from consumers." As part of that, carriers sold SMS separately. That made it easy for WhatsApp to find a way to replicate SMS using data, and then sell that to mobile customers for $1 a year. "But if WhatsApp gets big enough, then carrier strategy is going to change", he predicted. "You stop selling separate SMS plans and just have a take-it-or-leave-it overall package. And then suddenly WhatsApp isn't doing anything." The situation may have been different in countries other than the United States.
On January 18, 2016, WhatsApp's founder Jan Koum announced that the service would no longer charge their users a $1 annual subscription fee in an effort to remove a barrier faced by some users who do not have a credit card to pay for the service. He also explained that the app would not display any third party advertisement and instead would bring new features such as the ability to communicate with business organizations.
WhatsApp competes with a number of Asian-based messaging services (that as of 2014, were services like WeChat (468 million active users), Viber (209 million active users) and LINE (170 million active users)), WhatsApp handled ten billion messages per day in August 2012, growing from two billion in April 2012, and one billion the previous October. On June 13, 2013, WhatsApp announced that they had reached their new daily record by processing 27 billion messages. According to the Financial Times, WhatsApp "has done to SMS on mobile phones what Skype did to international calling on landlines."
In April 2014, WhatsApp crossed half-a-billion user mark.
In May 2014, WhatsApp crossed 50 million monthly active users in India, which is also its largest country by the number of monthly active users.
In October 2014, WhatsApp crossed 70 million monthly active users in India, which is 10% of its total user base (700 MM).
In February 2017, WhatsApp crossed 200 million monthly active users in India.
As of February 2017, WhatsApp has over 1.2 billion users globally.
In May 2016, some WhatsApp users were reported to have been tricked into downloading a third-party application called WhatsApp Gold. The application was part of a scam that infected the users' phones with malware. Another application called "GB Whatsapp" is also considered as a related scam. A message that promises to allow access to their WhatsApp friends' conversations, or their contact lists, has become the most popular hit against anyone who uses the application in Brazil. Since December, 2016, more than 1.5 million people have clicked and lost money
- WhatsApp Inc. (4 May 2017). "WhatsApp Messenger". App Store. Apple. Retrieved 4 May 2017.
- WhatsApp Inc. (14 April 2017). "WhatsApp Messenger". APKMirror. Android Police. Retrieved 15 April 2017.
- WhatsApp Inc. "WhatsApp Messenger". Windows Store. Microsoft. Retrieved 4 April 2017.
- WhatsApp Inc. "WhatsApp for Nokia S60". whatsapp.com. WhatsApp Inc. Retrieved 4 April 2017.
- WhatsApp Inc. (12 December 2016). "WhatsApp Messenger". BlackBerry World. BlackBerry. Retrieved 4 April 2017.
- "WhatsApp Messenger APKs - APKMirror". APKMirror.
- "WhatsApp Beta – Windows Apps on Microsoft Store". Microsoft Store.
- Ainsley O'Connell. "Inside Erlang, The Rare Programming Language Behind WhatsApp's Success". fastcolabs.com. Retrieved February 21, 2014.
- Metz, Cade (15 September 2015). "Why WhatsApp Only Needs 50 Engineers for Its 900M Users". Wired. Condé Nast. Retrieved 2 August 2016.
- Metz, Cade (5 April 2016). "Forget Apple vs. the FBI: WhatsApp Just Switched on Encryption for a Billion People". Wired (magazine). Condé Nast. Retrieved 13 May 2016.
- Voice calling, March 12, 2015
- "WhatsApp Voice Calling". April 4, 2015.
- Albergotti, Reed; MacMillan, Douglas; Rusli, Evelyn M. (February 20, 2014). "Facebook's $18 Billion Deal Sets High Bar". The Wall Street Journal. pp. A1, A6.
- "Facebook to Acquire WhatsApp" (Press release). February 19, 2014.
- Statt, Nick (February 1, 2016). "WhatsApp has grown to 1 billion users". The Verge. Vox Media. Retrieved April 6, 2016.
- Metz, Cade (April 5, 2016). "Forget Apple vs. the FBI: WhatsApp Just Switched on Encryption for a Billion People". Wired. Condé Nast. Retrieved April 5, 2016.
- Leo Sun (September 11, 2015). "Facebook Inc.'s WhatsApp Hits 900 Million Users: What Now?". The Motley Fool.
- Parmy Olsen (February 2, 2014). "Exclusive: The Rags-To-Riches Tale Of How Jan Koum Built WhatsApp Into Facebook's New $19 Billion Baby". Forbes. Retrieved January 14, 2015.
- Levy, Ari (19 February 2014). "Sequoia Said to Reap $3.5 Billion in Deal". Bloomberg.com. Retrieved 16 June 2016.
- McBride, Sarah (21 February 2014). "With WhatsApp deal, Sequoia Capital burnishes reputation". Reuters.com. Retrieved 16 June 2016.
- Wauters, Robin. "Sequoia Invests $8 Million In Messaging App Maker WhatsApp". TechCrunch.com. Retrieved 16 June 2016.
- Jan Koum (December 19, 2013). "400 Million Stories". WhatsApp Blog. WhatsApp. Retrieved January 17, 2014.
- Amit Chowdhry, "WhatsApp Hits 500 Million Users", Forbes, retrieved May 14, 2014
- Parmy Olsen (August 25, 2014). "WhatsApp Hits 600 Million Active Users, Founder Says". Forbes. Retrieved October 2, 2014.
- Christian de Looper (September 6, 2014). "WhatsApp to reach 3 billion users, Zuckerberg to invest billions". Daily Digest News. Retrieved September 7, 2014.
- Jayadevan PK (October 3, 2014). "Google planning to launch own mobile messaging app similar to WhatsApp". The Economic Times. Retrieved October 3, 2014.
- "WhatsApp Was Valued At ~$1.5B In Final Round Before Sale". Techcrunch. Retrieved February 22, 2014.
- Neal, Ryan W. (20 February 2014). "WhatsApp Investors Make Billions From Facebook Acquisition: Sequoia Capital Sees 50x Return on $1.3 Billion Investment". IBTimes.com. Retrieved 16 June 2016.
- "WhatsApp's Founder Goes From Food Stamps to Billionaire". Bloomberg News. Retrieved February 20, 2014.
- Dassanayake, Dion. "Twitter outrage as users claim WhatsApp has gone down days after Facebook purchase". Retrieved February 22, 2014.
- "Telegram saw 8m downloads after whatsapp got acquired Status". Retrieved February 27, 2014.
- "Line saw 2m new users after the outage of Whatsapp". Retrieved February 27, 2014.
- Lunden, Ingrid (February 24, 2014). "WhatsApp Is Actually Worth More Than $19B, Says Facebook's Zuckerberg, And It Was Internet.org That Sealed The Deal". TechCrunch. Retrieved February 24, 2014.
- Fitzsimmons, Michelle (February 24, 2014). "Mark Zuckerberg: WhatsApp is worth more than $19 billion". Techradar. Retrieved February 24, 2014.
- "President Hassan Rouhani issued order to 'hold WhatsApp service filteration'". BBC Persian. Retrieved May 27, 2014.
- Daftari, Lisa (May 4, 2014). "Iran bans WhatsApp because of link to 'American Zionist' Mark Zuckerberg". Fox News. Retrieved May 13, 2014.
- WhatsApp permitirá llamadas de voz, February 24, 2014, retrieved July 2, 2014
- Eugene Kim (January 7, 2015). "WhatsApp's Insane Growth Continues: 100 Million New Users in 4 Months". Business Insider. Retrieved January 13, 2015.
- Parmy Olsen (April 7, 2015). "Facebook's Phone Company: WhatsApp Goes To The Next Level With Its Voice Calling Service". Forbes. Retrieved April 18, 2015.
- Deepa Seetharaman (April 17, 2015). "WhatsApp Hits 800 Million Users — 1 Billion by Year-End?". The Wall Street Journal. (Dow Jones & Company). Retrieved April 18, 2015.
- Nate Ralph (April 18, 2015). "WhatsApp touts 800M monthly active users". CNET. Retrieved April 20, 2015.
- Guynn, Jessica (September 4, 2015). "Facebook's WhatsApp hits 900 million users, aims for 1 billion". USA Today.
- Natasha Lomas (December 1, 2015). "WhatsApp Is Blocking Links To Rival App Telegram On Android". TechCrunch. Retrieved December 7, 2015.
- Russell Brandom (November 30, 2015). "WhatsApp is blocking links to a competing messenger app". The Verge. Retrieved December 7, 2015.
- Martim Lobao (December 1, 2015). "[Update: Smoking Gun] WhatsApp Is Blocking Telegram Links In Its Android App". Android Police. Retrieved December 7, 2015.
- Ina Fried (January 18, 2016). "Facebook's Whatsapp is Now Free". Re Code. Vox Media, Inc. Retrieved January 18, 2016.
- "Whatsapp to Drop Subscription Fee". Wall Street Journal. Dow Jones & Company, Inc. January 18, 2016. Retrieved January 18, 2016.
- "Finally! Whatsapp removes $1 annual subscription fee". Phonearena.com. Phone Arena. January 18, 2016.
- Sarah Perez (June 24, 2016). "WhatsApp hits 100 million calls per day". TechCrunch. Retrieved June 24, 2016.
- "WhatsApp brings Two-step verification for Android 'beta' users: How to enable". November 11, 2016. Retrieved November 11, 2016.
- Madhumita, Murgia (May 18, 2017). "Facebook fined €110m by European Commission over WhatsApp deal". Financial Times. United Kingdom. Retrieved May 18, 2017.
- "WhatsApp Status: What is This New Snapchat-Like Feature?". February 24, 2017.
- "WhatsApp messenger for BlackBerry – Free Download". GetSpool – Jailbreak Tweaks, iOS News.
- Ash (April 9, 2015). "[Application] NEW Native WhatsApp clients hits the Tizen Store, Goodbye ACL WhatsApp Messenger". Tizen Experts.
- Cosmin Vasile (November 8, 2012). "Download Wazapp 0.9.12 for Nokia N9". softpedia.
- Mike Bowen. "Yappari v0.0.28. is Whatsapp on my Nokia N900.". My Nokia N900.
- "Whatsapp update adds support for Android Wear smartwatches". theinquirer.net.
- "WhatsApp for Pidgin". gosell.it.
- "WhatsApp Web". WhatsApp Blog. WhatsApp. January 21, 2015.
- "WhatsApp support for mobile devices". WhatsApp Blog. WhatsApp. 26 February 2016. Retrieved 16 July 2016.
- "WhatsApp support for mobile devices". WhatsApp Blog. WhatsApp.
- Kashmira Gander (January 21, 2015). "WhatsApp web: messaging client now available on internet browsers". The Independent. Retrieved January 23, 2015.
- Tweedie, Steven. "WhatsApp Is Now Accessible On The Web, But iPhone Users Are Out Of Luck". Business Insider. Business Insider. Retrieved February 2, 2015.
- "WhatsappTime Desktop Version With Superb Features". TricksWay.com.
- stonesam92. "Chit Chat A Mac app wrapper around WhatsApp's web client". GitHub.
- OSX Daily. "WhatsApp for Mac". OSXDaily.
- macupdate. "ChitChat for Mac". macupdate.
- "Introducing WhatsApp's desktop app", WhatsApp Blog, 10 May 2016, retrieved 11 May 2016
- Swanner, Nate (11 May 2016), "WhatsApp now has an official desktop app for Windows and Mac", The Next Web, retrieved 11 May 2016
- Shakal (March 22, 2011). "WhatsApp? Nicht ohne Risiken" [WhatsApp? Not without risks] (Google Translate) (World Wide Web log) (in German). DE. Retrieved January 29, 2013..
- Team Venomous (venomous0x). "Interface to WhatsApp Messenger" (blog). GitHub. Retrieved January 26, 2013.
- Amodio, Ezio (September 11, 2012). "Whatsapp – iOS password generation". IT. Retrieved January 29, 2013.
- Granger, Sam (September 5, 2012). "WhatsApp is using IMEI numbers as passwords". Retrieved January 29, 2013.
- "Wassapp login issues" (blog). Lowlevel Studios. December 11, 2012. Retrieved January 29, 2013.
Wassapp is a PC application developed to be a non-official client for WhatsApp Messenger
- Emenike, Kelechi (September 16, 2013). "Download WhatsApp on non-compatible Dual-SIM Phones" (blog). NG: ECHO. Retrieved September 29, 2013.
- "Why WhatsApp Will Remain" (blog). Retrieved March 17, 2015.
- "Whatsapp Video Calling" (blog). Retrieved Nov 18, 2016.
- "Whatsapp Video Calling" (News). Retrieved Nov 18, 2016.
- Team Venomous (venomous0x) (November 28, 2012) [May 29, 2012]. "WhatsAPI / README.md" (blog). GitHub. Retrieved January 29, 2013.
- Gaurav Rathee (June 25, 2015) [June 25, 2015]. "How WhatsApp Works" (blog). Retrieved June 25, 2015.
- Jon Evans (November 18, 2014). "WhatsApp Partners With Open WhisperSystems To End-To-End Encrypt Billions Of Messages A Day". TechCrunch. Retrieved November 19, 2014.
- "Open Whisper Systems partners with WhatsApp to provide end-to-end encryption". Open Whisper Systems. November 18, 2014. Retrieved November 18, 2014.
- "Facebook's messaging service WhatsApp gets a security boost". Forbes. November 18, 2014. Retrieved November 21, 2014.
- "Keeping Tabs on WhatsApp's Encryption". Heise Security. April 30, 2015. Retrieved April 30, 2015.
- Lomas, Natasha (April 5, 2016). "WhatsApp completes end-to-end encryption rollout". TechCrunch. AOL Inc. Retrieved April 5, 2016.
- Budington, Bill (April 7, 2016). "WhatsApp Rolls Out End-To-End Encryption to its Over One Billion Users". Deeplinks Blog. Electronic Frontier Foundation. Retrieved April 21, 2016.
- "WhatsApp Encryption Overview – Technical white paper" (PDF). WhatsApp Inc. April 4, 2016. Retrieved April 5, 2016.
- Open Whisper Systems. "libsignal-protocol-java". GitHub. Retrieved April 6, 2016.
- de Vries, Wilbert (May 21, 2011). "Fout in verificatiecheck Whatsapp maakt meelezen berichten mogelijk" (in Dutch). Tweakers. Retrieved August 24, 2016.
- Mutsaerts (May 20, 2011). "WhatsApp. Nu NOG lekker!" (in Dutch). Geenstijl. Retrieved August 24, 2016.
- McCarty, Brad (May 23, 2011). "Signup goof leaves WhatsApp users open to account hijacking". The Next Web. Retrieved January 29, 2013.
- Brookehoven, Corey (May 19, 2011). "Whatsapp leaks usernames, telephone numbers and messages". Your daily Mac. Archived from the original on May 23, 2011. Retrieved July 18, 2011.
- "Whatsapp ya cifra los mensajes" [What’s app already encrypts messages]. Mi equipo está loco (in Spanish). ES: IT Pro. May 11, 2012. Retrieved May 31, 2012.
- BB, David (May 8, 2012). "Twitter" (status). Retrieved May 31, 2012.
- Sp0rk bomb (May 10, 2012). "Twitter". Retrieved May 31, 2012.
- "WhatsApp is broken, really broken". File perms. September 12, 2012. Archived from the original on January 8, 2015. Retrieved July 2, 2015.
- djwm (May 13, 2012). "Sniffer tool displays other people's WhatsApp messages". H (online ed.). Heinz Heise. Retrieved January 29, 2013.
- "Are my messages secure?". WhatsApp (FAQ). Zendesk. August 15, 2012. Retrieved January 29, 2013.
- Schellevis, Joost (January 12, 2012). "WhatsApp status van anderen is nog steeds te wĳzigen" (in Dutch). Tweakers. Retrieved January 12, 2012.
- rvdm (January 12, 2012). "How What's app net works". Wire trip. Retrieved April 7, 2013.
- fab (September 14, 2012). "WhatsApp accounts almost completely unprotected". The H (online ed.). Heinz Heise. Retrieved January 26, 2013.
- crve (September 25, 2012). "WhatsApp threatens legal action against API developers". The H (online ed.). Heinz Heise. Retrieved January 26, 2013.
- wnstnsmth (September 30, 2012). "WhatsAPI sources back online". The H (online ed.). Heinz Heise. Retrieved January 26, 2013.
- "Crash Your Friends' WhatsApp Remotely with Just a Message". TheHackerNews. December 1, 2014. Retrieved December 1, 2014.
- "Multiple Vulneribilities found in Whatsapp Web". Hackatrick. January 29, 2015. Retrieved January 29, 2015.
- "17-Year-Old Found Bugs in WhatsApp Web and Mobile App". TheHackerNews. January 29, 2015. Retrieved January 29, 2015.
- "WhatsApp adds support for document sharing, but only PDFs at launch". TechCrunch. March 2, 2016. Retrieved March 2, 2016.
- "Your mobile could be at risk if you don't deactivate the new function on WhatsApp". Softonic. March 7, 2016. Retrieved March 7, 2016.
- Manisha, Ganguly (13 January 2017). "WhatsApp vulnerability allows snooping on encrypted messages". The Guardian. Retrieved 21 February 2017.
- Dan, Goodin (13 January 2017). "Reported "backdoor" in WhatsApp is in fact a feature, defenders say". Ars Technica. Retrieved 21 February 2017.
WhatsApp does not give governments a "backdoor" into its systems and would fight any government request to create a backdoor. The design decision referenced in the Guardian story prevents millions of messages from being lost, and WhatsApp offers people security notifications to alert them to potential security risks. WhatsApp published a technical white paper on its encryption design and has been transparent about the government requests it receives, publishing data about those requests in the Facebook Government Requests Report.
- "There is no WhatsApp 'backdoor'". OWS Blog. January 13, 2017. Retrieved January 15, 2017.
- "WhatsApp vulnerability explained: by the man who discovered it". The Guardian. 16 January 2017. Retrieved 17 January 2017.
- Perez, Evan; Prokupecz, Shimon (December 17, 2015). "First on CNN: Paris attackers likely used encrypted apps, officials say". Retrieved March 27, 2017.
- Sparrow, Andrew (March 26, 2017). "WhatsApp must be accessible to authorities, says Amber Rudd". The Guardian. Retrieved March 27, 2017.
- Osborne, Samuel (April 10 2017). "Stockholm suspect Rakhmat Akilov 'exchanged Whatsapp messages with Isis supporter before and after attack'". Independent. Retrieved April 10, 2017.. Check date values in:
- Wisniewski, Chester (January 29, 2013). "WhatsApp's privacy investigated by joint Canadian-Dutch probe". Naked security. Sophos. Retrieved January 29, 2013.
- "Investigation into the personal information handling practices of WhatsApp Inc.". Findings under the Personal Information Protection and Electronic Documents Act (PIPEDA). Report of Findings. Privacy Commissioner of Canada. January 15, 2013. 2013-001. Retrieved January 29, 2013.
- gh, h (January 28, 2013). "WhatsApp could face prosecution on poor privacy". IDG. CXO Media. Retrieved January 29, 2013.
Dutch and Canadian privacy commissioners conducted a yearlong investigation into the popular mobile app
- "Legal Info". WhatsApp. July 7, 2012. Retrieved January 29, 2013.
- "Dutch DPA: WhatsApp non-users better protected". November 3, 2015.
- "Whatsapp now lets you disable Read notifications". November 15, 2014.
- tech2 News Staff (February 13, 2015). "WhatsApp security flaw allows anyone to track you regardless of your privacy settings". Firstpost. Retrieved April 23, 2015.
- Jan Koum (August 25, 2016). "Looking ahead for WhatsApp". WhatsApp. Retrieved August 25, 2016.
- James Vincent (August 25, 2016). "WhatsApp to start sharing user data with Facebook". The Verge. Retrieved August 25, 2016.
- Lomas, Natasha (26 August 2016). "How to opt out of sharing your WhatsApp info with Facebook". TechCrunch. AOL Inc. Retrieved 4 September 2016.
- "CITC warns Skype, Viber, WhatsApp". Saudi Gazette. Jeddah. March 31, 2013.
- ULD empfiehlt nach dem WhatsApp-Facebook-Deal: „Wechseln“ (german)
- "Whatsapp adds end-to-end encryption". BBC News. April 6, 2016. Retrieved April 6, 2016.
- Lee, Micah (2 March 2015). "You Should Really Consider Installing Signal, an Encrypted Messaging App for iPhone". The Intercept. First Look Media. Retrieved 12 January 2016.
Apple’s iMessage ... employs strong encryption, but only when communicating between two Apple devices and only when there is a proper data connection. Otherwise, iMessage falls back on insecure SMS messaging.
- "Requirements for enhanced security features". Viber Security FAQ. Viber. n.d. Retrieved 16 July 2016.
Note that Viber for Windows Phone 8 will not support the new security features. It will continue to secure calls and messages through standard encryption methods.
- "Secure Messaging Scorecard. Which apps and tools actually keep your messages safe?". Electronic Frontier Foundation. April 5, 2016. Retrieved April 6, 2016.
- "Brazilian Judge Lifts Ban on Facebook's WhatsApp". The Wall Street Journal. Retrieved December 17, 2015.
- "WhatsApp blocked in Brazil for 48 hours by court". The Guardian. Retrieved December 17, 2015.
- "PF prende executivo do Facebook por empresa não liberar dados do WhatsApp" (in Portuguese). Folha de São Paulo. March 1, 2016. Retrieved March 1, 2016.
- "'Felizes', diz Facebook sobre soltura de vice-presidente preso em SP". March 2, 2016.
- "Brazilian Judge Puts Temporary Ban on WhatsApp". Wall Street Journal. Retrieved 2 May 2016.
- "WhatsApp Ordered Blocked Again in Brazil Over Data Dispute". Bloomberg. Retrieved 2 May 2016.
- "Brazilian appellate judge rescinds WhatsApp block". Ars Technica. Retrieved 4 May 2016.
- Yglesias, Matthew (February 19, 2014). "What's the WhatsApp Endgame?". Slate. Retrieved February 22, 2014.
- Corbin, David (November 5, 2014). "Surprise! Viber surpasses Line in monthly active users".
- Horwitz, Josh (October 9, 2014). "Line finally reveals it has 170 million monthly active users".
- Olanof, Drew (August 23, 2012). "WhatsApp hits new record with 10 billion total messages in one day". The Next Web. Retrieved January 29, 2013.
- Sushma, Parab (April 4, 2012). "WhatsApp founder to operators: 'We're no SMS-killer, we get people hooked on data'". The Next Web. Retrieved January 29, 2013.
- Olanoff, Drew (October 31, 2011). "WhatsApp users now send over one billion messages a day". TheNextWeb. Retrieved January 29, 2013.
- WhatsApp, 27 Billion msgs handled in just 24 hours! (µblog), Tweeter,
New daily record: 10B+ msgs sent (inbound) and 17B+ msgs received (outbound) by our users
- Bradshaw, Tim (November 14, 2011). "WhatsApp users get the message". The Financial Times. London. Retrieved January 29, 2013.
- "WhatsApp crosses half-a-billion user mark; strong growth in India and Brazil". The Indian Express. April 23, 2014.
- Rajat Agrawal. "WhatsApp crosses 50 million monthly active users in India, ties up with Airtel for special data plans". Retrieved May 11, 2014.
- PTI News. "WhatsApp user-base crosses 70 million in India". Retrieved November 3, 2014.
- "WhatsApp user-base crosses 200 million in India". Retrieved March 2, 2017.
- Statt, Nick (2016-02-01). "WhatsApp has grown to 1 billion users". The Verge. Retrieved 2016-05-23.
- Bolton, Doug (24 May 2016). "WhatsApp Gold: Scammers trick mobile phone users into downloading malware". The Independent. Independent Print Limited. Retrieved 8 August 2016.
- Novo golpe de Whatsapp atinge 1,5 milhão de vítimas em 3 meses by Eduardo F. Filho (2017)