Co–Star: My Test of the Astrology App That Sends Me Insults

Hoping for a little encouragement from the stars? Co–Star would sometimes rather send an insult straight to your phone. The astrology app combines personal readings with friendship compatibility checks and quips that range from funny to absurd. I gave it a try: What’s behind the hype, which messages make you scratch your head—and which features are actually useful in everyday life?

Co–Star: From insider tip to universal approval

When I told the editorial team about my supposedly new app discovery, the reaction was rather one-sided: five heads turned toward me, and the moment I said Co–Star, everyone enthusiastically agreed. In this room full of millennials, I hadn’t unearthed some hidden gem—I was simply late to the party.

I first heard about the app from a friend on vacation. Her pitch sounded tempting: Instead of a generic horoscope for my star sign, I’d get daily readings based on my personal birth chart. There was also a feature for comparing friendships astrologically. My curiosity was piqued. But would the app still hold my interest after the initial thrill of discovery wore off?

What the app does with your birth chart

Co–Star is algorithm-based and uses your so-called birth chart as its foundation. This is an astrological map of the planets’ positions at the time of your birth. The app says it uses data from NASA to create one. From that, it generates personalized horoscopes designed to stand apart from generic star-sign readings.

Co-founder Banu Guler describes the idea as bringing astrology and spirituality into the digital age. The visuals fit the concept: black and white, a minimalist design, plus images of statues and beetles. There’s no colorful, sparkling starry sky here. The interface feels understated—a striking contrast to some of the completely out-there messages.

You can also find your birth chart as a table with brief explanations. It gives you an overview of the planets and the personality traits associated with them. It’s a clear way to get an introduction, but don’t expect an in-depth exploration of every individual placement.

A friendship check with plenty to talk about

What really drew my friend in, though, was the social feature. You can add other users by name or phone number and then see how astrologically compatible you are. For my relationship, it was mostly amusing: Seeing our differences laid out like that made us laugh rather than argue.

A friend who was already having doubts about her relationship didn’t enjoy the comparison as much. That’s exactly why I wouldn’t use these assessments as a yardstick for a relationship. If a result makes you uneasy, talk to the person involved rather than treating an app’s reading as a verdict on your connection.

The novelty also wears off. Once you’ve clicked through the profiles of your friends, the big reveal is over. The app does offer daily takes on how the others are supposedly feeling and whether you should seek closeness or keep your distance. Still, I rarely look at them.

From thoughtful to completely absurd: tips for interacting

Co–Star also suggests things you could do with a particular person or keep in mind when dealing with them. Some advice sounds perfectly sensible: Pay attention to the signals the other person is sending. Other suggestions are much stranger, like showering someone with sincere compliments.

Then there are ideas that veer all the way into the absurd: We’re supposed to dress up as mimes and make meaningless gestures at each other. Excuse me? Moments like these make the app entertaining, but not necessarily helpful. My practical approach: take what’s useful and file the rest away as bizarre conversation fodder. These astrological stage directions certainly can’t replace real human connection.

Push notifications: cheeky, cryptic, and sometimes pretty mean

Co–Star has made a name for itself with its short daily prompts and push notifications, which also circulate as memes. Under “Your day at a glance,” there’s a sentence meant to get you thinking. In my case, though, it often just made me furrow my brow in confusion. Sometimes I laughed; often, all I could think was: What am I supposed to do with this?

For example, some users have received messages that essentially told them there was no point in being sad. Another message flat-out declared that trying to be understood was futile. That’s not gentle encouragement; it’s a pretty harsh tone. If you’re looking for reassurance, this might not make you feel seen.

To me, that’s the app’s most striking tension: It wants to feel personal, but it doesn’t always strike the right tone. A short sentence might be funny, completely off the mark, or simply incomprehensible. You don’t have to take it personally just because it appears on your screen.

Do’s and don’ts: three bullet points, plenty of questions

I find the lists under the daily horoscope even more puzzling. Three bullet points each are supposed to show me what to do and what to avoid. But sometimes there’s a world of difference between a piece of advice and a single English word. These examples left me especially baffled:

• “Test Drive”: a test drive—but of what?
• “Cellar Doors”: cellar doors. What am I supposed to do with those?
• “Theme Songs”: theme songs as the day’s agenda?
• “Sea legs”: getting your sea legs—without any helpful context.
• “Permanent Marker” under the don’ts: a specific prohibition or a metaphor?
• “Identity Theft,” also under the don’ts: an extraordinarily odd warning.

Below that, “Peaking tomorrow at …” tells me when my best time is supposed to be. I just can’t figure out what I’m meant to do with that information. I usually forget the time almost as soon as I’ve read it.

Why I still keep checking the app

Fortunately, Co–Star isn’t all cryptic one-liners. I find the longer daily horoscopes much more pleasant. They sound friendlier, provide more context, and occasionally offer thoughts that help me get through a bad day. When certain astrological alignments are in play, the app adds further explanations and tips.

Whether by chance or not, sometimes the readings fit my mood surprisingly well. That makes them a small prompt for everyday life—not a prediction I’m expected to follow.

My real favorites are the “Ice Breaker” prompts. They offer short statements about me, as well as takes on my friends. One particularly delightfully weird question was about the voice in my head: Mine said “Existence is a prison,” while a friend’s said “Elevator music.” Existential dread meets elevator music! It’s exactly these kinds of contrasts that make us laugh and take screenshots.

Different houses? Check your settings

When I compared the app with a birth chart I’d already had calculated, I noticed that two planets had been assigned to different houses. The key is in the settings: Under “Settings” and “House Systems,” you can choose between “Porphyry,” “Placidus,” and “Whole Sign.”

Co–Star uses Porphyry by default. Many other birth chart calculators use Placidus. So if your results differ, first check whether you’re using the same house system. Different placements don’t automatically mean you’ve found a calculation error.

My verdict: entertaining, yes; life director, no

For me, Co–Star is neither a reliable relationship adviser nor a daily must-check. The free, algorithm-based app entertains me with absurd ideas and occasionally offers a comforting thought. Its cryptic messages, on the other hand, are often useless.

If you want to explore your horoscope for fun and have a laugh with friends, you might enjoy it. If you’re looking for a detailed, personalized exploration of astrology, you may be disappointed. I’m keeping the friendly readings and funny screenshots—the supposed cosmic commands can stay behind.