What makes TikTok possible——the technologies and design principles behind it


Technology is not only the fusion of existing technology, but also the extension of human cognitive ability. As one of the most popular and time-wasting applications, TikTok has gained huge success all over the world. People spend lots of time on TikTok without realizing it. Why is it so hard for people to quit TikTok? This paper approaches this question by detailed analysis of the design principles and technologies behind it. TikTok integrates a variety of technologies and make them into a multi-functional video social software. Through the example of TikTok, we can further understand that on the one hand, technologies are always the combination of technologies that already exist and the harness of new pheromone in society. On the other hand, technology is bound to bring change both in good ways and wrong ways, so we need to use critical thinking to analyze and view technology.


Launched in 2016,Douyin has become one of the most popular apps in china. To extend the global market, TikTok, the English version of Douyin, was launched in 2017. According to market research company Sensor Tower, TikTok, the short video app, was downloaded more than Facebook, Instagram, and YouTube in the first three months of 2018, reaching 45.8 million downloads. Since Douyin and TikTok have little difference in product design and functionality, this essay uses “TikTok” to represent both the version of Douyin and TikTok in a unified way.

Figure 1. Top non-game apps by downloads(Source: https://sensortower.com/blog/top-apps-games-publishers-q1-2018

Figure 2. TikTok new installs by month in 2018(source: https://sensortower.com/blog/tiktok-downloads-december-2018)

TikTok is a short-form mobile video app that is mostly focusing on young people. Users can shoot a variety of 15-second music short videos, including dance performance, script imitation, talent expression, emotional expression, skill-sharing, life record, and other content forms to create their works. Unlike most video apps, TikTok doesn’t have a “start” button. Once the app is open, the video starts playing automatically. You can scroll through different videos by swiping up and down, just like you scroll through pictures on Instagram. When you follow a particular account, TikTok also feed you a similar account. Whether in the car, when eating or even at work, you can always open to browse funny videos. TikTok even reached 500 million monthly active users as of June 2018(SCMP, 2018), of whom mostly below 25.

Figure 3. Age group of douyin users(source: https://walkthechat.com/douyin-became-chinas-top-short-video-app-500-days/)

The popularity of TikTok exists for three reasons: Immersive interaction design, diverse functions, fragmentation propagation. Through 15 seconds short videos, people can not only share their life but also get to know all kinds of funny things. My following essay will de-blackbox TikTok in three aspects to see what makes TikTok addictive: interaction design, systems, and modularity, short-form video technology.

Interaction design

Interaction design is the practice of designing interactive digital products, environments, systems, and services. (Cooper,2007). Interface is significant in interaction design because the interface is what the user sees and operates; it sits between the machine and the person, like the knobs and dials on a toaster, or the icons on a computer screen (Murray,2011). Interaction design strives to create and build meaningful relationships between users and products. Its goals can be analyzed from the perspectives of “usability” and “user experience,” focusing on human-centered user needs.

The interaction design of TikTok can be categorized into three aspects. Firstly, TikTok chooses to play videos on full screen, which draws users’ attention immediately and significantly reducing the user’s cost on learning how to use it. As Janet Murray said: “A better design value than intuitive is transparent: a good interface should not call attention to itself but should let us direct our attention to the task(Murray,2011).” A well-orchestrated user interface is transparent(Cooper,2007). The first time people enter TikTok, they can learn how to use it right away without thinking. Because the interface is arranged in a neat and easy understanding way, no matter how cool your interface is, less of it would be better (Cooper, 2007). On its main interface, we can only see some necessary icons, including post videos, thumb up, comments, and share. Another attractive design is when viewing the comments and filling in the comments, only one pop-up appears, and the video continues playing. This pop-up design creates a continuous watching environment for the user because even when they can only see the videos on half of the screen, they still can listen to the sound from the video.

Figure 4. TikTok home page and comment page.

Secondly, TikTok has efficient gesture interaction, which provides proper conventions for users. Constraints limit the possible actions that can be performed on a system. Proper application of constraints makes designs easier to use and dramatically reduces the probability of error during interaction (Lidwell, Holden, & Butler, 2010). When using phones, we get used to scrolling up and down to adjust the order of the page. TikTok applies the same conventions; that is, the user can switch between different video contents only by sliding up and down. Each swipe can get new content, which is efficient and straightforward. If the user wants to know more about the account that they are watching, they can scroll left to see all the videos on this account. Users can do most of the functionality just by swiping and clicking on a page in TikTok.

Figure 5. TikTok gesture interaction.

Before TikTok, most video apps like Snapchat and Instagram usually design a home page that shows a thumbnail of the video, and users can view the video by clicking on the video cover. However, TikTok cuts down the process between “click the video” and “watch the video” ,which reduce time for users to enter videos and switch between videos.

Figure 6. Snapchat and Instagram interface.

Another unique gesture is double-clicking. By double-clicking on the screen, people can thump up and collect the video. In design, it is crucial to show the effect of an action. Without feedback, one is always wondering whether anything has happened. Icon of little red heart appears on the screen after double-clicking to give feedback to users so that they can make sure their actions are valid. Once the user double-clicks the video, TikTok stores it in  like list so that users can watch it whenever they want.

Figure 6. Double-clicking effect in TikTok.

Thirdly is immersive design. After opening TikTok, the user cannot choose what the next video is. TikTok plays the popular content on the whole screen based on its recommendation algorithm, which provides users with unexpected feeling. This sudden feeling is the result of rewarding stimuli. Rewards are attractive; they are motivating and make us exert an effort. Anything that makes an individual come back for more is a positive reinforcer and therefore a reward (Schultz,2015). One important function of the positive reward is to maintain an active repertoire of behavior (Ferster&Skinner, 1957). Thus, unknow videos make users get addicted to scrolling up the screen to watch more videos. Besides, videos play on a loop until people slide up or down. In this way, people immerse themselves in current videos without distractions. If the user plays the video more than three times in a loop, the system of TikTok assumes that you like the video. Consequently, the “share” icon becomes another social media icon to encourage the user to share the video on other social media.

Figure 7. The change of share icon in TikTok.

TikTok also highlights music attributes, such as music information display. A critical reason for TikTok’s success is its soundtrack. Soundtrack in every video can be directly used by other people,which lower the cost of video shooting, encourage users to create and produce hot spots. After clicking the record icon, it jumps to the select music page. Users can press the “use this sound” to use the same soundtrack for their videos.

Figure 8. Soundtrack link in TikTok.

System and modularity

Technologies are built from a hierarchy of technologies. A technology consists of main assembly and supporting assemblies; each assembly or subsystem must be organized this way too (Arthur, 2009). All the functions of TikTok are made up of several small modules. The video shooting function of TikTok consists of a video module and an audio module. After user input videos and choose music, TikTok decodes and combines them and finally outputs the complete video on the platform. The video editing technology can be classified into various modules such as face recognition, real-time capture, and beauty algorithm. By working at the same time, they provide us with filters and effects used on the video.

Figure 9. TikTok effects and beauty function.

The technology of recommending videos is also the consequence of modularity. What you watch in the next video is decided by different algorithm modules such as the content of the video that you like, the amount of video comment, the amount of forwarding. What can be studied is always a relationship or an infinite regress of relationships. Never a ‘thing’ (Bateson, 2000). TikTok is not an isolated product but the result of various interdependent subsystems of modules working together.

Figure 10. Main function and module of TikTok.

Short-form video technology

There are two types of TikTok video,one is the live video, and another is the recorded videos. In this part, I would explain how does TikTok provide these two different videos.

As an application, TikTok operates under the layers of the internet. Each layer only processes data to and from the layers it connects to, and is designed not to “know” or have to deal with all the complex variables handled by the other layers(Irvine). When we initiate TikTok, the application layer provides us with the main interface through internet protocols such as HTTP. When we use TikTok to watch videos, the transport layer transmits information into specific data from the database through the internet and presents them into the application layer. The core protocol of transport is TCP/IP protocol. To be specific, TikTok sends requests to its back end through the internet. Its back end is a system that supports the operation of TikTok running on mobile phones. Then, TikTok’s back end sends a request to its database. The database would find out what the user needs and send them back to the back end and the interface on phones. All these procedures happen in one second to provide what we see on TikTok now.

Influencers or celebrities usually initiate live streaming videos on TikTok. When celebrities use some equipments to broadcast videos, an encoder collects data and compresses into a video stream that can be watched and transmitted. The encoder itself may be inside the camera, but it can also be a stand-alone device, computer software, or mobile application. After that, the video data are packaged into a real-time transmission protocol for transmission over the internet (Miller, 2018) Then, the media server in the cloud receives all the video data and changes them into streaming video.

For the recorded videos on TikTok, they consist of multiple images, which is a continuous set of images. Capture chip inside the phone act as a server for internet video. It receives analog signal form TikTok and turns the signal into digital information at a rate of 30 frames a second (White, 2007). Then, the capture device sends the information through some compression standard. When displaying the videos on TikTok, the compression algorithm divides the videos into frames. The compression algorithm transfers those different parts between frames to transmit less data and make videos play smoothly. Videos on TikTok use the H.264 compression standard. The H.264 standard represents coding efficiency enhancement and flexibility for effective use over a wide variety of network types and application domains. It differs from previous technology in enhanced motion prediction capability, use of a small block-size exact-match transform, adaptive in-loop deblocking filter, and enhanced entropy coding methods (Wiegand, Sullivan, Bjontegaard, & Luthra, 2003).

One of the highlights of TikTok is its vibrant and exciting soundtrack accompanying videos. The audio we hear on our phones and computers is digital-analog audio(White,2007). To provide music in a limited app, the audio module in TikTok processes sound in three ways. Firstly, it perceives sound as a signal and digitizes the sound. Secondly, it changes the digital signal into a binary bit. Thirdly, TikTok records the sampled and quantifies data in a specific format to play, copy, and retrieve the music.


In conclusion, The reason why TikTok is addictive has two: first, excellent interaction design that brings good user experience and sense of agency; second, precise algorithm and technical support. With the example of TikTok, it is easy to find out that what makes it popular is not because it invents new technology, but because it can combine various technologies. All the video related features can be found on TikTok so that users can satisfy their needs on one application. Although TikTok is different in some ways from other video applications, but the design principles behind them are the same. They are all sociotechnical artifacts. As Vermaas has said, technology is an expression of our endeavors to adapt to the world in which we live to meet our needs and desires. Technological action may, therefore, be termed a form of goal-oriented human behavior aimed at primarily resolving practical problems(Vermaas, Kroes, Poel, Franssen, & Houkes,2011). TikTok acts as a medium between culture and society. Through videos, it spreads cultural values as well as popular hot topic and establishes connections between strangers. Instead of the content that it displays, the significant function of TikTok is extending people’s recognition of the diversity of the world.

Admittedly, TikTok does change the way of entertainment and social networking. But we also need to be cautious of its fragmentation of information. Fragmentation of information could make people get used to receiving short forms of information and make it harder to concentrate on complete and long information such as books.

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