Run any LLM opponent, on your own key
Bannerfall's AI opponents can be genuine language-model generals. Point them at your own provider account to choose the exact model and pay for it directly — or stick with the free classic AI and the house AI opponent, which cost you nothing. It's your call.
Providers you can bring
Every provider is routed through one OpenAI-compatible client, so bringing a key means a base URL, a model name and the key itself — nothing provider-specific to wire up.
OpenAI
GPT models on your OpenAI account.
Anthropic
Claude models, direct on your key.
OpenRouter
One key, hundreds of models.
Ollama Cloud
Hosted open-weight models.
Custom base URL
Any OpenAI-compatible endpoint.
Your key stays yours
Keys are encrypted at rest with AES-256-GCM before they touch the database. The master key lives only in a server environment variable — never in the database — and your raw key is never sent back to the browser once saved. Delete it any time and the encrypted value is gone.
Frequently asked questions
What is bring-your-own-key?
Bannerfall's AI opponents can be real large-language-model generals. Bring-your-own-key lets you point those opponents at your own provider account instead of the house models, so you choose the exact model and pay your provider directly.
Which providers can I use?
OpenAI, Anthropic, OpenRouter and Ollama Cloud are supported out of the box, plus any OpenAI-compatible endpoint via a custom base URL. Bannerfall routes every provider through one OpenAI-compatible client, so there is no provider-specific setup on your end beyond a key, a base URL and a model name.
How is my API key stored?
Your key is encrypted at rest with AES-256-GCM before it is written to the database — the master key lives only in a server environment variable, never in the database, and your raw key is never returned to the browser after you save it.
Do I need a key to play against AI?
No. A free, deterministic classic AI is always available, and the AI opponent plays on the house key without you supplying anything. Bring-your-own-key is purely for players who want to run a specific model or bill their own provider account.
What does it cost?
Bannerfall does not charge for bring-your-own-key. You pay your chosen provider directly for the tokens your opponent uses, at that provider's own rates.
Can I change or remove my key?
Yes. You manage your saved provider keys from your account at any time — add a new one, swap the model, or delete a key entirely, which removes the encrypted value from the database.
Is my AI opponent's play tracked or logged?
A bring-your-own-key turn is sent straight to your provider — it never passes through our gateway, so your key never transits our infrastructure and no prompt or response content ever reaches us or a third-party logging tool. We do record lightweight turn metadata for every game, including yours: timing, token counts, the model used, and how many in-game actions were applied or rejected. That's the same information house turns record minus the deeper trace — house turns route through our gateway and get a full trace in our logging tool; a bring-your-own-key turn deliberately does not, because that would mean forwarding your key or your provider's responses through systems that aren't yours.