Environment Variable Reference
Copy .env.example to .env at the repo root and fill in the values below.
For production, set these as system environment variables or via your deployment platform's secrets manager — not as a .env file.
Required
| Variable | Example | Description |
|---|---|---|
STT_API_KEY | dg-... | Deepgram API key (STT) |
TTS_API_KEY | dg-... | Deepgram API key (TTS — same key) |
LLM_API_KEY | sk-or-... | OpenRouter API key |
STT
| Variable | Default | Description |
|---|---|---|
STT_PROVIDER | deepgram | STT provider name |
TTS
| Variable | Default | Description |
|---|---|---|
TTS_PROVIDER | deepgram | TTS provider name |
TTS_VOICE | aura-2-thalia-en | Deepgram voice ID |
LLM
| Variable | Default | Description |
|---|---|---|
LLM_PROVIDER | openrouter | LLM provider name |
LLM_BASE_URL | https://openrouter.ai/api/v1 | OpenAI-compatible base URL |
LLM_MODEL | openai/gpt-4o-mini | Model slug |
TURN / ICE
| Variable | Default | Description |
|---|---|---|
TURN_PROVIDER | static | cloudflare or static |
TURN_KEY_ID | — | Cloudflare TURN key ID |
TURN_API_TOKEN | — | Cloudflare TURN API token |
TURN_TTL_SECONDS | 3600 | Credential TTL |
TURN_SERVER | — | Static TURN URI e.g. turn:host:3478 |
TURN_USERNAME | — | Static TURN username |
TURN_PASSWORD | — | Static TURN password |
Server
| Variable | Default | Description |
|---|---|---|
HOST | 0.0.0.0 | Bind address |
PORT | 8000 | Listen port |
System Prompt
| Variable | Default | Description |
|---|---|---|
SYSTEM_PROMPT | — | Inline system prompt string |
SYSTEM_PROMPT_FILE | — | Path to a .txt file containing the system prompt |
When mode=flow, the YAML settings.base_system_prompt takes precedence over these variables.
Minimum Production Set
STT_PROVIDER=deepgram
STT_API_KEY=dg-...
TTS_PROVIDER=deepgram
TTS_API_KEY=dg-...
TTS_VOICE=aura-2-thalia-en
LLM_PROVIDER=openrouter
LLM_API_KEY=sk-or-...
LLM_BASE_URL=https://openrouter.ai/api/v1
LLM_MODEL=openai/gpt-4o-mini
TURN_PROVIDER=cloudflare
TURN_KEY_ID=...
TURN_API_TOKEN=...
HOST=0.0.0.0
PORT=8000
Getting API Keys
- Deepgram — console.deepgram.com
- OpenRouter — openrouter.ai/keys
- Cloudflare TURN — Cloudflare Dashboard → Calls → TURN credentials