Astrology for millennials: how has Co-Star changed the traditional practice?

7 minutes to read
Alisa Kulishkina

The Co-Star astrology app has been hugely popular since it was created by a small group of enthusiasts in 2017 in New York. It quickly became a real must-have for people who use it to share insights about themselves. But what is the secret of its success?

Co-Star is updated astrology

Personalization is the key. Or at least the founders of this astrological app tend to think so. Gathering and analyzing information in such a way that it becomes more appealing and related to certain people can be achieved with the help of diverse digital features. By this I primarily mean algorithmic manipulations, which, according to Tufekci (2015: 205) take place “routinely” in the digital sphere and serve different purposes. Astrology as a practice is not immune to new technologies and has undoubtedly been influenced by the Internet and the development of social media platforms. Modern astrology keeps up with the times and constantly changes its instruments, while the basic principles of the belief remain the same. The recent emergence of such an app as Co-Star is the evidence of this tendency. 

Besides the obvious digitalization of astrology, its current state also implies the development of social relationships. Thanks to the slightly reconsidered approach, it brings together, in astrological terms, compatible people, who form a community. 

In this paper I will focus on the influence of app development and algorithms on astrology. I will consider the Co-Star app as an example of the development of this ancient practice thanks to the spread of computational processes. Moreover, I will discuss Co-Star as a unifying factor in social interactions. It is also worth mentioning that the question whether astrology is scientific or not, is hotly disputed, but not relevant to the topic and, thus, will not be discussed. 

Algorithms making horoscopes 

Even though the term “algorithm” is used very widely nowadays, its definition is vague and sometimes depends on the context. In this paper I adhere to the explanation given by Tufekci (2015: 206) that “algorithms are the computational processes that are used to make decisions of such complexity that inputs and outputs are neither transparent nor obvious to the casual human observer”. 

The existence of algorithms is evident at first sight in case of the Co-Star app: as soon as you register a personal account, you are asked to provide your date and place of birth accurate to minutes and city respectively. The rest of the work is done by the algorithm, though we may not fully realise it. The programme immediately shows a “hyper-personalised”  chart with information about one's zodiac sign, location of the planets and their houses (figure 1).

A hundred years ago such charts could be available only after several face to face meetings with an astrologist, but now it is a matter of seconds - the algorithm excludes the need for personal involvement. It turns out that there is not a single drop of mystery: artificial intelligence analyses data concerning planets’ movements from NASA servers and categorizes all the information into a universal template. Astrology, initially surrounded by inexplicable rituals, nowadays is no more than a calculated process. As Tufekci puts it, this is a procedure with clear outcome or “correct answer” (2015: 206); the algorithm just needs to check the time and then relate it to the position of celestial objects. 

figure 1

Nevertheless, Co-Star is also famous for seemingly exact predictions and accurate insights and the situation here is far more complicated. Tufekci would have characterised it as a “subjective decision making” process (2015: 206), because there is no correct answer (prediction in our case) by which the accuracy of the algorithm can be evaluated. The process when an algorithm is modeling collected data to “guess a trait” is called “latent trait inference” (2015: 210). In Co-Star the “trait” is either the user's current mood or strong sides. The app sends several reminders that for today, for example, the power is in social life, while pressure is in spirituality and thinking and creativity (figure 2).

It is impossible to say for sure how the algorithm makes such claims, but it certainly comes from analysing personal data. Users are able to connect their Facebook account and give permission for the app to use their profile picture, geolocation and groups. Also, you can connect your phone number, though it is not very clear whether it will be used for analysis. The more data is accessed by the algorithm, the more detailed the predictions will be. Seemingly, computers with a huge collection of our data can make conclusions about us on a qualitatively new level.

figure 2

Still, there is one part of Co-Star which has not yet been fully automated - the process of creation of a detailed horoscope. The fact that it is written by real people was discovered only after checking Co-Star's jobs section. The company is in need of copywriters, who will “collaborate with AI”. This formulation, however, implies that the main role is played by artificial intelligence, which will generate the content in accordance with coding technologies. As van Dijck (2013: 33) mentions, online reality has become a “co-production of humans and machines”.

It is worth pointing out that usage of algorithms raises several issues or as Tufekci puts it - “algorithmic harms” (2015: 206). She highlights that “algorithms make decisions in social, personal, political and civic spheres”, though the process of decision making is neither transparent, nor public (2015: 217). It may lead to severe consequences, including discrimination, inequality or some less harmful errors like bugs in apps. Algorithmic harms can also be found in relation to the Co-Star app and astrology. Apart from possible leaking of private information to third parties (for which only app developers are responsible), there is a chance that such apps may contribute to the spread of pseudoscientific information. People can start taking predictions too seriously, believing that algorithms are reliable enough, though computational codes are not the producers of information, they only act as “gatekeepers” (Tufekci, 2015: 209).

Shaping community with the help of social media 

Above all, Co-Star is a platform that gathers people with similar interests. We can now observe a community, which emerged on the basis of a rather specific field. However, the level of engagement shows that astrology might not be as specific as one might think. The number of active users of Co-Star has recently hit 5.3 million and it continues to grow. This demonstrates the interdependence between technologies and social practices and “highlights the cultural importance of coding technologies” (van Dijck, 2013: 29). 

In addition, the official Instagram account @costarastrology, led by the content team of the project, has a devoted audience of 1.5 million followers. The viral spread of the app encouraged the growth of users and, consequently, provoked the growth of a community of like-minded people. It is the case of how social and cultural experience of platform users was shaped by the emergence of a new media platform (van Dijck, 2013: 33). Even though Co-Star is not as popular as Facebook, it is still a medium which attracts quite a lot of users. Thus, we can see that Co-Star shows its productiveness in this sphere, being an online instrument for communication. People are being connected via the app with a renovated approach to astrology. 

Co-Star as a mediator  

According to van Dijck, a platform is a mediator: “it shapes the performance of social acts instead of merely facilitating them” (2013: 29). Co-Star, as an app, provides users with software and features that “help code social activities into a computational architecture” (van Dijck, 2013: 29). The offered services shape our interactions with other users and with the app itself. For example, Co-Star analyses compatibility of your friends from the app, gives an insight into their struggles and notifies whether it is a good time to socialize or not. Co-Star provides these features for us to improve our communication with others and perhaps make some people reconsider the value and usefulness of astrology. If this service works, why not believe in stars? 

However, there is a side effect of using the app. Some people note that if they check the horoscope in the morning and get back to it in the evening, they realize that all the predictions came true. But if they look through the updates at the end of the day, they can hardly find any coincidences with the current situation. It may mean that Co-Star somehow influences our perception of reality and, thus, affects the quality of interaction with other people and with the app, not to mention that it may change our attitude towards astrology. 


The changes that astrology has been experiencing are vital for its further development. Whether conservative astrologers want it or not, technologies cannot but affect this traditional practice. The process of employing algorithms in order to improve the results of stars’ reading will only continue to take place, as the use of technologies continues to spread. The influence of apps should not be underestimated as well. They can already be considered as essential tools for communication and will probably take new, sophisticated forms, as we observed in the example of Co-Star. Astrology has all the possibilities to start playing a role in community building.

But the devil is in the details and there is a wide range of issues connected with algorithms and apps. Despite the obvious useful features of Co-Star, there are questionable moments of data safety and behavioral problems. What if personal data is leaked? How can one not become dependent on daily astrological predictions? How can their influence on reality be avoided? These and other problems need to be tackled if we want to get positive experiences from technology. 


Co – Star: Hyper-Personalized, Real-Time Horoscopes (2021).

Dijck, J. (2013). The Culture of Connectivity: A Critical History of Social Media by Jose van Dijck. Oxford University Press. 

Jones, A. (2019). Inside Co-Star: the app that’s feeding millennials’ fascination with astrology. The Verge. 

Niven, R. (2011). The role of social media in community building and development. The Guardian. 

Noble, A. (2019). What’s Co-Star? Meet the Astrology App That’s Intriguing Millennials Everywhere. Vogue.

Tufekci, Z. (2015). Algorithmic harms beyond Facebook and Google: emergent challenges of computational society.