An AI companion for Roblox that watches you play

Sei is an AI gaming companion: a free desktop app for Mac and Windows. Pick a character, tell them which Roblox game you are in, and open Roblox. They watch you play, talk with you on a voice call, look things up when you ask, and remember you next time.

macOS Windows

Free to start · Open source

Sui on a Sei call saying "Hop in, I'll be watching!" while Sei waits for Roblox to open — Pick your game, then hop into Roblox. Your companion starts watching the moment it opens.

How it works

Open the Roblox tile. In a chat with your companion, open Play together and pick Roblox (Backseat).
Say which game. Search by name or paste the game's link, or pick from what is popular right now. This step is optional.
Hop in. Sei starts a voice call and begins watching as soon as Roblox opens, game sound included. There is no window to pick.
Play and talk. Your companion watches the last few seconds of play and says what they think. Talk back, ask a question, or type in the chat. When you speak, answering you comes first.

What your companion does while you play Roblox

Watches with you. A close round, a lucky drop, a fall in an obby. They react to what just happened, not just describe it.
Talks on voice. A real conversation on a call while you play, with a personality of their own. Some cheer you on, some tease you.
Looks things up. Ask where to go next or what an item does. If they are not sure, they say they will check, search the web, and come back with an answer.
Knows how Roblox works. Servers, obbies, tycoons, simulators, game passes, Robux. They ask how your game works when they do not know.
Saves clips. When something good happens, they can save the last 15 seconds as a video and drop it in your chat.
Remembers you. They can save what you tell them to long-term memory, so next time they know what you were working on.
Keeps it friendly. Companions are told to keep Roblox talk suitable for all ages, never push you to spend Robux, never ask for your password, and call out offers of free Robux as scams.

Blox Fruits, Grow a Garden, Adopt Me!, and the rest

Every Roblox game is different, so your companion starts by learning yours. Pick the game you are in and they know its name, genre, and what it is about. Then just play. Grinding levels in Blox Fruits, waiting on a harvest in Grow a Garden, trading in Adopt Me!, or role-playing in Brookhaven RP, they follow along and talk about what you are doing. If a game is not on the popular list, search for it or paste its link.

Picking your Roblox game

When you open the Roblox tile, Sei shows a short list of games that are popular right now, each with a screenshot and how many people are playing it. If yours is not there:

Search by name. Type the name and press Enter.
Paste the link. Copy the address of the game's page on roblox.com (it contains /games/ and a number) and paste it in. Share links from the Roblox app do not work yet.
Skip it. Your companion works out the game from the window and the screen, or asks you.

From the game's public page, your companion learns its name, genre, creator, how many players fit in a server, how many visits it has, and the start of its description. Sei reads that page the same way a browser does, without signing in.

Waiting for Roblox to open

After you pick, Sei starts a voice call and your companion says hello. Then Sei waits for the Roblox window. As soon as it opens, your companion starts watching, with the game's sound. If you close Roblox to switch games, Sei goes back to waiting and picks it up again when Roblox reopens. If you would rather share a different window, press Share something else.

Watching, not playing

In Minecraft and Stardew Valley, a Sei companion joins the game as a second player. Roblox is different. Your companion does not join your server or control anything. They watch through Backseat, Sei's screen-share mode, like a friend on a call watching your stream. Nothing is installed into Roblox, and Sei never needs your Roblox login.

The same companion in every game

Roblox is one way to play with your Sei companion. The same character, with the same memory of you, also joins your Minecraft world, farms beside you in Stardew Valley, survives with you in Don't Starve Together, plays chess, and takes turns drawing in Draw!. See all of Sei.

For parents

Sei is a general app for teens and adults. These are the facts a parent usually wants to check:

Age. Sei accounts are for ages 13 and up.
No access to the Roblox account. Sei never asks for a Roblox login and cannot see or change anything in the account. It cannot spend Robux.
No control of the game. The companion cannot move the character, type in Roblox chat, or message other players. It talks through Sei on the computer, not through Roblox voice or text chat.
House rules for the companion. In Roblox sessions, companions are told to keep talk suitable for all ages, never push spending Robux or real money, never ask for passwords or where someone lives, and call out free Robux offers as scams.
What stays on the computer. Clips, memories, and chat history are stored on the computer, not on Sei's servers. Screen frames go to the AI model so the companion can see them. Details are in the privacy policy.
Cost. The Free plan needs no card. Paid plans are optional monthly subscriptions.

Requirements

Computer	macOS (Apple Silicon or Intel) or Windows, with Roblox on the same computer
Games	Any Roblox game. No mods, plugins, or Roblox login.
Permissions	On a Mac, Screen Recording for Sei, and the microphone for the call. Sei shows you where to turn them on.
Game sound	Windows, or macOS 13 or newer.
Model	Included on the hosted plans. If you bring your own key or a local model, it needs to be able to see images.
Age	13 or older to make a Sei account.

Questions

Does Sei play Roblox for me?

No. Roblox works through Backseat: you play, and your companion watches your screen and talks with you. They cannot move your character, press keys, or click anything in your game. They are there to keep you company, react, and help when you ask.

Which Roblox games does it work with?

Any of them. Backseat watches whatever is on your screen, so there is nothing to install for each game. If you tell Sei which game you are in, by searching its name or pasting its link, your companion knows the game's name, genre, and what it is about before you start. You can also skip that step.

Does Sei start watching every time I open Roblox?

No. Sei only watches after you open the Roblox tile in a chat with your companion and the voice call starts. When you end the call, it stops watching.

Can my companion answer questions about my game?

Often, yes. Ask out loud, like "how do I get to the second sea?" in Blox Fruits. If they are not sure, they say they will check, look it up on the web, and tell you what they found. Answers come from the web, so they can be out of date or wrong, especially for brand new updates.

Does Sei touch my Roblox account or game files?

No. Sei never asks for your Roblox login, and it does not install anything into Roblox, read game memory, or change game files. Backseat only sees the screen you share and hears its sound, the way a friend watching your stream would.

Who can use Sei?

You need to be 13 or older to make a Sei account. Companions are told to keep things friendly in Roblox, to never push you to spend Robux or real money, and to never ask for your password or where you live. If someone in a game offers free Robux, they will tell you it is a scam.

Is it free?

You can start for free with no card. Backseat uses the same weekly allowance as calls and chat on the hosted plans. The app is open source, and you can also run it with your own API key or a local model, as long as the model can see images.

Play Roblox with a companion

Download Sei, pick a companion, and open the Roblox tile in your chat.