Frequently asked questions

Vivarium is a long-form AI roleplay and world-simulation app that runs in your browser. You play a character of your own inside a world that keeps its own records: places, items, time, and what every character knows, wants and thinks of you.

The AI narrates and gives every character a voice. The application decides what actually happens. The principle is one line: The AI controls expression. The application controls reality.

In a chat, one model does everything. It remembers what it can, decides what happens and writes the reply, and over a long story it forgets, drifts and agrees with you.

In Vivarium the world is stored as records, not as text the AI is trusted to re-read. Your action is resolved against those records and the dice are rolled before any prose exists. The narrator is then told what happened and writes it. Nothing it writes becomes true on its own. The devblog post How a turn works walks through one turn, and the features page lists everything that follows from it.

Not yet. Vivarium is in development and nothing is launched. The target for a first playable release is the first quarter of 2027. That is a target, not a promise, and if it moves it moves on the roadmap first.

There is no waiting list. To follow along, subscribe to the devblog by RSS.

One developer, Jeffrey Torres, who builds it to solve the problem he runs into every time he sits down to play. The About page has the longer version.

The one you choose, or one Vivarium provides. On the free plan, and on the subscription with your own key, you connect your own account with an AI provider that offers an OpenAI-compatible interface, and you pick the model that narrates each story. You pay your provider directly for what you use.

On the subscription with the model included, Vivarium provides a tested model. You need no provider account and no key.

Your key is encrypted the moment it is stored and is never shown again, to anyone. It is decrypted only inside the application at the moment a call to your provider is made. It is never written to a log, a usage record or an error message.

A turn that carries a decision makes up to three model calls: one to work out what your action means, one to narrate, and one to check that the narration does not contradict the outcome. A turn that is only talk makes fewer.

That is more than a single-call chat, and on your own key you pay for it, so it is stated plainly. The application records the token usage of every call so you can see what a story spends. On the subscription with the model included, turns come out of the monthly allowance instead.

Not every model. Vivarium needs strict structured answers as well as good prose, and some models cannot give them. Before a model runs a game, a readiness check tells you whether it can. It runs on your own key, tells you the rough token cost before it starts, and never runs silently. Its results build a shared list of models known to work, and nobody who ran a check is named in it.

A model that writes good prose but cannot give structured answers is marked Narration only. It can still run a story, and you are told plainly what that costs: your actions are not interpreted into decisions, and the narration is not checked against the outcome.

There will be a free plan and one subscription. No price is set, so none is given here.

The free plan is the whole game at the table: the play screen, decisions and checks, honest dice, consequences, travel, time and the living world that catches up when you skip it, and taking a turn back. You play the starter worlds, write your own characters in full, convert the character cards you already have, and download what you wrote. On the free plan you bring your own provider key.

The parts that cost money to run, and the worlds that take the longest to write. Both ways to subscribe include all of it:

Premium worlds. Every premium world in the catalogue is included, and more are added over time.

World authoring. Create and edit your own worlds: places, people, items and lore. Clone a catalogue world and change your copy privately.

Deep memory. On the free plan a story keeps a bounded amount of memory in play. Subscribed, memory is deep and permanent. Nothing is deleted on the free plan. Older memories are kept and return to play when you subscribe.

More stories at once. The free plan allows a small number of active stories.

The subscription comes two ways, and they differ only in who provides the model. Everything else is the same.

With your own key. You connect your AI provider, as on the free plan, and your provider bills you for what your stories use.

With the model included. Vivarium provides the model. There is no provider account and no key to set up. A monthly allowance comes with it, and a meter shows how much is left. When the allowance runs out, play continues on a lighter model until the month resets. There is no hard stop and nothing extra to pay for. If the model's provider is down, a second provider steps in, and every turn names the model that wrote it.

You can switch between the two in the app. Neither price is set yet.

No. Nothing in Vivarium is bought one piece at a time. No world is sold on its own, no character card is sold, and there is no shop. The subscription is the only thing anyone pays Vivarium for.

On the subscription with the model included, yes. Your stories' model calls come out of a monthly allowance, and play continues on a lighter model once it is spent. With your own key, on the free plan or the subscription, your provider bills you for the model calls your stories make.

One small exception is planned for the subscription with your own key. When the narrator writes lines for your character, a cleanup call removes them. For subscribers Vivarium pays for that call itself, tells you so, and lets you switch any single story back to your own key.

Nothing is deleted. A lapse changes what you can do, never what you have.

What stays fully yours: the worlds you wrote, your clones of starter worlds, your characters and the stories set in them. They stay in your library, stay playable within the free plan, and stay downloadable. Editing worlds is part of the subscription, so editing returns when you resubscribe.

What pauses: stories set in premium worlds, and your clones of premium worlds. A paused story stays readable. You can open it and read everything so far, but you cannot take a turn. When you resubscribe it resumes exactly where it was.

Pausing happens only when the subscription has actually ended, after the payment processor has finished its normal retries. A first failed payment pauses nothing. The cancel screen shows the date the subscription ends, lists every story and clone that will pause, and says that nothing is deleted.

One catalogue of worlds written for Vivarium, which you can browse, search and preview. Five starter worlds are planned for launch and are open to everyone: a fantasy adventure, a mystery in one town, a science-fiction ship or station, a survival world after a collapse, and a historical port town with no magic. The port town is a free slice of Edrath, a much larger world that sits in the catalogue as a premium world. A starter world is complete but focused: fewer places, a smaller cast, and its hooks placed in scenes you walk into.

Larger worlds carry a Premium mark and come with the subscription. They are full worlds, with factions, routines and events in depth. Everyone can see them in the catalogue, and a subscriber can play every one of them. On the free plan a premium world can be seen but not opened or started.

Separately, each world is labelled General or Mature so you know what you are walking into. That label is a filter and it locks nothing. The two marks are independent: a premium world can be General and a starter world can be Mature.

Yes, with the subscription. You author places and how they connect, people, items, a lore book, the skills a check can be rolled against, and the living world: factions with goals, routines with wages, world events, groups and merchants. Each story runs on its own copy of the world, so editing a world never changes a story under way.

Subscribers can clone a catalogue world and change the copy privately. The copy is frozen against its source, so an update to the original never reaches it. A clone of a premium world stays marked as premium, and it pauses with your other premium stories if the subscription ends.

Subscribers can also turn a story's world, as it stands, into a world of their own and start a new story from it.

Not in the first release. Everything you make stays in your own account. Hosting what strangers upload brings moderation, authorship disputes and legal duties that one developer cannot carry honestly. Sharing will be looked at again after launch. The reasons are set out in The road to launch.

Yes, on every plan. Someone who spends fifty hours on a world should never be unable to get it back out. You can download the worlds and characters you wrote as files that carry no secrets. Restoring a file to the account it came from is planned before launch.

Catalogue worlds, and clones of them, cannot be downloaded by anyone on any plan. They are not your writing to take out, however much of the copy you changed.

That is planned for launch. A card, as a JSON or PNG file, or a lore book is converted rather than imported. The file is read as text, your own model proposes a Vivarium character from it, the application validates the proposal strictly, and you review it before anything is saved. Values the model had to guess are marked as guesses. The card's instruction fields are shown to you and then dropped, because nothing a file says gets to instruct the narrator.

Converting a card is open on every plan. It runs on your own key and there is nothing to pay Vivarium for it. A lore book converts into a world, so it is part of world authoring and comes with the subscription.

That is planned for launch, for any character you wrote. The download is a JSON character card produced directly from the stored fields, with no model call, so the same character always gives the same file. A character's secrets are left out unless you choose to include them.

The trip is lossy in both directions. Skills, conditions, relationships, beliefs, memories and every underlying number have no place on a card, and they stay behind. Characters from catalogue worlds and their clones cannot be downloaded.

No. Time belongs to you. The world does not run on a real clock, and coming back after a month finds it exactly as you left it. The world moves when you move time: rest an hour, wait out the night or skip a week, and the application works out who went where and what changed. You then get a digest of what your character could plausibly have learned.

This is the same on every plan. Over a skip, characters age, needs rise, a promise breaks when its deadline passes, and the wider world is worked out: schedules, factions, events and rumours.

Yes. What a character does is decided from their goals, fears, values and how they feel about you, with dice bounded by their personality. They can refuse, bargain, lie, hold something back or walk away. Refusal is a normal result, not an error.

Yes. Insult someone, threaten them, help them, rescue them or apologise, and the application records the moment. It moves how that character feels about you, and how everyone who saw it feels, by a size set by the story's stakes. A note under the reply says who will remember.

A flash of anger or fear fades with time. The deed does not, and waiting forgives nothing. A second apology counts for less than the first, and no repair outweighs the harm it answers.

A promise you make is kept as an open thread. Keep it and the person you made it to remembers. Break it and they remember that too. If the promise has a deadline, letting the deadline pass breaks it, on every plan.

The people who saw it know. If they belong to a faction, or live where it happened, your standing with that faction or place moves, and the cause is written down in words.

With the subscription, word also travels to people who were not there, sometimes exaggerated, and reaches you as news when you move time forward. Enough deeds of one kind earn your character an epithet, used only by characters who know those deeds.

Yes, two ways. Earn it back through deeds their members see, or pay amends to a member. Paying raises your standing one step, at most once a day of world time, and never past neutral.

No. The outcome is rolled and recorded before the narrator is called. The narrator is told what happened and never sees the roll or the odds. For outcomes that bind, such as a failure or a refusal, a separate check reads the prose, and narration that contradicts the result is rejected before it reaches the story.

Yes. Every change a turn makes is written down with its cause and with what is needed to reverse it. Retracting a turn puts the items, the injuries and the opinions back where they were. You can also stop, regenerate or edit recent turns.

Facts, scene summaries, memories held by each character, and threads left unresolved, all stored as records. Each character speaks only from what that character knows, so a character can be wrong, keep a secret or repeat a rumour. You can open the memory inspector, read what the world remembers, and correct it.

Connect an embedding model and the application also finds memories close in meaning, not only in wording. The inspector says why each one came up.

No. Nothing one player makes is visible to another player. There is no public catalogue of player content, and every story, world and character belongs to the account that made it.

Vivarium is for adults, and sign-up will ask you to declare that you are 18 or over. Vivarium puts no content filter on your private play. Your own AI provider's rules apply to what its model will write. When a provider declines to write a scene, Vivarium tells you so plainly and never stores the refusal as part of your story.

There is one hard limit: sexual content involving minors is never allowed. Nothing Vivarium itself publishes in the catalogue is sexually explicit.

Account deletion is planned before launch. It erases your data, with a grace period in case you change your mind, and signing in during that period cancels the deletion. You can download what you wrote first.

Write to hello@vivariumonline.com.