The words "Just So You Know" written in sand on a beach.

If someone has ever told you something you didn’t really ask to know, they probably also told you “JSYK.” Here’s what that internet initialism means and when to use it.

“Just So You Know”

JSYK stands for “just so you know.” It is used to share a piece of information or comment with someone who didn’t request it. It can be used to start a conversation, or it can come up in the middle of a discussion with someone. It bears a lot of similarities to the popular FYI or “for your information.”

While the initialism can be written in both uppercase “JSYK” and lowercase “jsyk,” the lowercase version is much more popular online in messages and social media.

One thing to note is that sharing something with “JSYK” may be considered rude, depending on what you say and its context. For example, while you might consider it helpful, providing sudden criticism can be considered unwarranted by the person you’re talking to.

The Origin of JSYK

JSYK can be traced back to the earliest days of message boards and internet chats in the 1990s and the 2000s. The first definition of the acronym on Urban Dictionary is from 2005, and humorously calls it an “internet lazy phrase intended to save keystrokes.” Considering the number of terms that were shortened during the period, this interpretation seems very likely.

The acronym has become widely used in the last decade in conjunction with the adoption of direct messaging apps such as WhatsApp, Viber, and Apple iMessage. JSYK is a popular term that is often used between friends, family, and acquaintances. In real-life conversations, however, the full phrase “just so you know” is more common.

Giving Unsolicited Information

A person typing on a smartphone.

JSYK is mostly used to give someone information that they didn’t explicitly ask for, but that you think would be useful for them to know. For example, if someone’s about to drive off to grab food downtown, it might be useful for you to say, “JSYK, the traffic tonight is really heavy.” While they don’t need to know that, the information will help them determine their route and options.

Sometimes JSYK can start a conversation on its own. When using the acronym to begin a cold message, you should follow it immediately with the significant info you want to share.

Another use of JSYK is sharing details about your life with someone else. If you got a promotion recently, you might message them “JSYK, I just got promoted.” Reactions to this use of the acronym vary. This can be an annoying use of the acronym for the other user, as they may or may not actually care about what you’re sharing.


JSYK bears a lot of resemblance to another, more famous acronym, FYI, which means “for your information.” These acronyms aim to provide someone with information that you think they might need, but that they didn’t necessarily ask for.

The biggest difference between the two is that FYI tends to be more professional, while JSYK tends to be more casual and personal. FYI is commonly used in professional and journalistic settings and often prefaces company emails, reports, or fun facts. It has also been part of the English language for over 100 years and is frequently spoken aloud in its acronym form.

On the other hand, JSYK tends to appear more in casual conversations between friends and acquaintances who are sharing personal tidbits about themselves or updates about their lives. The acronym is rarely spoken out loud compared to the full phrase “just so you know,” which makes it a term more exclusive to the internet.

How to Use JSYK

If you’re texting or messaging someone, you can use JSYK to share all kinds of information with other people. Examples include helpful tips, recent updates about mutual friends, and important current events.

Here are a few ways to use JSYK:

  • “jsyk, I think we’re out of milk.”
  • “It’s raining outside, jsyk.”
  • “JSYK, I think Julien is about to propose next month.”
  • “Paprika is supposed to be really good for this recipe, jysk.”

If you want to learn about other online slang terms, check out our articles on TBH, BRB, and TIL. You’ll be texting like a digital native before you know it.

RELATED: What Does "TBH" Mean, and How Do You Use It?

Profile Photo for Vann Vicente Vann Vicente
Vann Vicente has been a technology writer for four years, with a focus on explainers geared towards average consumers. He also works as a digital marketer for a regional e-commerce website. He's invested in internet culture, social media, and how people interact with the web.
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