n8n-nodes-slng is a community node for n8n. It brings two nodes to your workflows: SLNG, which runs text-to-speech, speech-to-text, and outbound voice-agent calls, and SLNG Trigger, which lets a voice agent call a workflow as a tool mid-call. Both share one credential and reach every model on the SLNG platform.
Install
In your n8n instance, go to Settings → Community Nodes, click Install, and enter the package name:This is a community node, so it needs a self-hosted n8n instance. n8n Cloud does not support unverified community nodes.
Credentials
Create an SLNG key in the dashboard, then add a SLNG API credential in n8n and paste it. The key is sent as a Bearer token and validated againstGET https://api.slng.ai/v1/me. The same credential covers both the Voice API (api.slng.ai) and the Agents API (api.agents.slng.ai).
Actions
The SLNG node runs one operation per execution:| Resource | Operation | What it does |
|---|---|---|
| Text to Speech | Generate | Converts text into spoken audio, returned as a binary file on the item. |
| Speech to Text | Transcribe | Transcribes an audio file from a binary field into text. |
| Agent | Dispatch Call | Places an outbound phone call from a SLNG voice agent. Checks the agent has outbound telephony configured before dispatching. |
Trigger
The SLNG Trigger node registers a webhook tool on an existing agent when you activate the workflow, and removes it when you deactivate. When the agent calls the tool during a call, the workflow runs.- Tool type — LLM tool (contextual): the agent decides when to call it, and you define the parameters it sends with a field builder (name, type, description, required). System tool: fires automatically on a call lifecycle event (call start, first user message, call end, tool succeeded or failed).
- Authentication — HMAC (SLNG signs the body with
X-Signature-256) or Bearer. Leave the secret empty to auto-generate one on activation; the node registers it with SLNG and validates incoming requests. - Respond — Using Last Node (default) returns the workflow’s final output to the agent. Immediately acknowledges the call and runs the workflow in the background. To shape the JSON the agent receives, keep Using Last Node and have the final node emit the object you want.
n8n blocks expression access to
$json.arguments, so the trigger exposes the agent’s tool arguments as toolArguments. Reference them downstream with {{$json.toolArguments}} or {{$json.toolArguments.fieldName}}.Next steps
Agent skills
Let a coding agent build your SLNG integration instead.
Voice agents
Build and configure the agents you dispatch and trigger from n8n.
GitHub repo
Setup guide, version history, and ready-made workflow templates.