ComfyUI Node
arkennemasis fal · xAI Grok Voice · $0.00083/s
Build real-time voice applications powered by Grok. Send recorded audio and get a voice and text response. Pricing (from fal, 2026-09-29): $0.00083 per second (fal's billing unit). Model page: https://fal.ai/models/xai/grok-voice Key: FAL_KEY in the .env next to run_nvidia_gpu.bat. Results are saved in output/fal/xai_grok-voice/.
arkennemasis fal · xAI Grok Voice · $0.00083/s
- audio
- audio
- audio_path
- text
- duration
- info
◄prompt►
◄voice(not set)►
◄tools{"x_search": {"enabled": false}, "web_search": {"enabled": false}, "mcp_servers": []}►
◄max_cost_usd20.0►
◄reuse_identical_runtrue►
◄extra_json►
◄max_concurrent1►
Categoryarkennemasis/fal/Audio/xAI
Inputs (8)
| Name | Type | Default | Description |
|---|---|---|---|
| audio | AUDIO | URL of the audio containing the user's speech. The Grok agent listens to it and replies with speech. Most common audio formats are supported; the audio is converted to 16-bit 24 kHz mono PCM before being sent to Grok. Maximum duration 10 minutes, maximum file size 50 MB. | |
| prompt | STRING | Optional system instructions describing the agent's persona and conversation context. Uses Grok's default persona when omitted. Empty leaves it out. | |
| voice | COMBO | (not set) | Built-in xAI voice for the agent's reply. Uses Grok's default voice when omitted. '(not set)' leaves it to the model. |
| tools | STRING | {"x_search": {"enabled": false}, "web_search": {"enabled": false}, "mcp_servers": []} | Typed xAI tools supported by this app's convenience configuration. Every tool is disabled in the default configuration: the searches must be switched on via their ``enabled`` flags and ``mcp_servers`` starts empty. ``file_search`` / collections are intentionally absent and unsupported due to Zero Data Retention (ZDR) requirements. Caller-side function tools are likewise absent from the typed configuration — they requ |
| max_cost_usdopt | FLOAT | 20.00–100000 | Safety cap. If the estimated cost of this run is above this many US dollars the node stops BEFORE sending anything to fal. 0 = no cap. |
| reuse_identical_runopt | BOOLEAN | true | If these exact inputs (the settings AND the same pictures/clips/audio) were already paid for and the files are still in output/fal, return them instead of paying again - also after a ComfyUI restart. Turn off for a fresh take with the same settings. |
| extra_jsonopt | STRING | Advanced: a JSON object merged into the request last, for any fal field this node has no box for. Example: {"seed": 7}. Leave empty normally. | |
| max_concurrentopt | INT | 11–32 | How many paid fal calls may run at the same time in one run, across every fal node. 1 (default) = one after another. This node starts its paid part only while fewer than this many fal calls are running. Once any fal node fails, the ones still waiting are not started, so nothing more is billed. |
Outputs (5)
| Name | Type | Description |
|---|---|---|
| audio | AUDIO | — |
| audio_path | STRING | — |
| text | STRING | — |
| duration | FLOAT | — |
| info | STRING | JSON: request id, cost estimate, saved files and fal's full answer. |