SillyTavern API: Connect FreeTheAI (Custom OpenAI)
SillyTavern talks to FreeTheAI through its Chat Completion API with the Custom (OpenAI-compatible) source. It lists every model your key can use.
Steps
Open API Connections
Click the plug icon in the top bar.
Choose the source
Set API to Chat Completion and Chat Completion Source to Custom (OpenAI-compatible).
Enter the endpoint and key
Paste the base URL into Custom Endpoint (Base URL). SillyTavern adds /chat/completions itself, so do not add it. Paste your key into Custom API Key.
Pick a model and connect
Type a model ID into Enter a Model ID, or pick one from Available Models after connecting. Press Connect.
Set Prompt Post-Processing
On the same screen, set Prompt Post-Processing to Semi-strict. With None, some models answer "Bad Request" because the chat can reach them without a message from you.
How this guide was checked: Checked against SillyTavern's source (release branch, API connection panel) on 2026-09-29.
Tips
- Your key is hidden after you press Connect. Keep a copy somewhere safe.
- If replies stop early, raise Max Response Length in the sampler panel.
- Save the connection as a Connection Profile to switch models quickly.
Troubleshooting
SillyTavern connects but no models appear. What now?
Type the model ID by hand in Enter a Model ID, for example glm-5.3. Also check that your account follows a provider of that model.
Should the base URL end in /v1?
Yes. Use https://api.freetheai.org/v1. SillyTavern appends /chat/completions.
SillyTavern says "API returned an error: Bad Request". How do I fix it?
Set Prompt Post-Processing to Semi-strict in API Connections and try again. Some models need at least one message from you in every request, and that setting makes sure there is one.
Common errors
- 401: the key is wrong or incomplete. Paste the whole key.
- 403: follow a provider of the model, or confirm your email.
- 404: the model ID or URL is wrong.
- 429: daily limit reached, or too many requests at once.