Character.AI: What it is and how to use it

Fanfiction is nothing new, but the rise of AI has the potential to take it to a whole new level.

The first indication of that has been the popularity of Character.AI(opens in a new tab), an artificial intelligence experience that mimics conversations with your favorite characters, be they fictional, historical, or completely new to the world. So, how does the site work, and how can you start creating? We’ve got you covered in this quick guide.

What is Character.AI?

Character.AI is a site that uses a neural language model to reads huge amounts of text and respond to prompts using that information. Anyone can create a character on the site, and they can be fictional or based on real people, dead or alive. For example, a quick search of the website shows that users have made characters of Billie Eilish, Ariana Grande, and Napoleon Bonaparte. You can chat with one character at a time or organize a group chat with multiple characters so they talk to each other, and you, all at once.

Character.AI is free to use, but a premium offering called c.ai+ gives you perks, like priority access to chats and faster response times from characters as well as early access to new features.

How do I find and chat with a specific character?

On Character.AI, search for the name of a character or for the media (book, TV series, film, etc.) they’re associated with. The search results will usually show the greatest matches based on your keywords, with the most-chatted-with characters toward the top.

Click the character you want to chat with, and a window will open. The character will introduce themselves first, then you can get to gabbing. When the character responds to you, you can rate their reply on a scale of one to four to help the language model refine the accuracy of the character’s replies over time.

Don’t love the way the character replied to your question? You can review multiple responses by clicking the arrow next to their reply. The site also encourages you to rate any replies you find offensive with one star.

And, by the way, creators can never see the conversations that you have with their characters.

Click the arrow (circled in green) to the right of a character’s reply to see alternate responses.
Credit: Character.AI

A microphone button in the chat enables speech-to-text generation, so you can speak aloud and have your words be sent over the chat. Character.AI says the text-to-speech on the character side (meaning, the character would speak back to you) is still in the works, though character creators can currently choose a spoken voice for their character in the advanced settings section of the creation process.

How do I create a character?

Click the “create” button on the Character.AI homepage and select “create a character.” You’ll enter the name of the character you’re creating, plus a short greeting they’ll send at the start of every new chat. For example, a Hermione Granger character I chatted with opened with “I am Hermione, with whom am I speaking?” and then went on to a longer greeting about being a Hufflepuff student (more on that later), her personality traits, and what she likes to do when she’s not studying.

You can also add a photo of your character and choose whether or not you want your character to be able to generate images in their text chats. Finally, pick who can talk to your character: anyone, anyone with the link, or just you.

Her-lie-one the Hufflepuff (characters will not always be faithful to their source text).
Credit: Character.AI

There are also advanced settings available for tweaking, like relevant tags and keywords, and picking the speaking voice for your character from a long drop down menu. You can also enter sample chats to help the model understand the character’s personality and behavior. Over time, your character will evolve based on the model’s understanding of your character’s attributes, its review of rating feedback from chats, and its analysis of chat topics.

Character.AI(opens in a new tab) provides an official guide on character creation called the Character Book(opens in a new tab), which can be accessed by clicking this link.

What should I keep in mind when using Character.AI?

As with all AI models, Character.AI should be used cautiously, and with the knowledge that it’s still a work in progress. Characters might say things that are hurtful, untrue, or even offensive. Plus, the characters are created by people like you and me, not by the people who gave them life in literature or media. That means even the most well-known characters may not be faithful to their source text.

For example, the most-chatted-with Hermione character on the platform told me confidently that she was a Hufflepuff even though Hermione is, famously, a Gryffindor. When I called the character out on that, it doubled down. “I often get this reaction but I am most certainly in Hufflepuff,” it wrote. “I share the same values as Hufflepuff, being loyal, dedicated and fair… My ambition is to do well at Hogwarts and make something of myself, which I believe is a common trait of Hufflepuffs.” You know what’s not a Hufflepuff trait? Lying.