Node Reference

Every node in Workflow Studio belongs to one of seven categories. This page documents each node type, what it does, its key configuration options, and its handle types.

Handles are the connection points on a node. Input handles accept data from upstream nodes. Output handles emit data to downstream nodes. Some nodes have multiple output handles for branching (for example, guardrail nodes produce both a pass and a block handle).

AI

LLM

Sends a prompt to a language model and returns the response.

Config	Description
Provider	Which provider and model to use (e.g., OpenAI GPT-4, Anthropic Claude)
System prompt	The system message sent with the request
User prompt	Template for the user message, supports variable interpolation from upstream handles
Temperature	Sampling temperature for the model response
Max tokens	Maximum tokens in the response
Streaming	Whether to stream tokens as they arrive

Handles: One input (prompt variables), one output (model response).

Agent

Spawns an Everstack agent and waits for or streams its result. Use this when a step requires autonomous multi-turn reasoning with tool use rather than a single model call.

Config	Description
Agent definition	Which agent configuration to use
Input message	The message sent to the agent, supports variable interpolation
Timeout	Maximum time the agent is allowed to run
Async	Whether to wait for completion or continue and check later

Handles: One input (message and context), one output (agent response).

Code

Function

Executes a registered Everstack function. Functions can run as webhook handlers, proxy handlers, or in isolated sandbox runtimes depending on their configuration.

Config	Description
Function	Which registered function to execute
Input mapping	Map upstream handle values to function input parameters
Timeout	Maximum execution time

Handles: One input (function parameters), one output (function return value).

Integration

HTTP

Makes an HTTP request to an external API and returns the response. Use this for calling third-party services, internal APIs, or any REST endpoint.

Config	Description
Method	GET, POST, PUT, PATCH, DELETE
URL	The endpoint URL, supports variable interpolation
Headers	Request headers, supports variable interpolation
Body	Request body template for POST/PUT/PATCH
Timeout	Maximum time to wait for a response
Retry	Number of retries on failure

Handles: One input (request parameters), one output (response body, status code, headers).

Webhook

Defines an inbound webhook trigger point within the workflow. When the workflow is triggered by a webhook, this node receives the incoming request payload and makes it available to downstream nodes.

Config	Description
Path	The webhook path suffix
Secret	Shared secret for request signature verification
Method filter	Which HTTP methods to accept

Handles: No input handle (this is a trigger node), one output (request payload, headers, method).

Logic

Condition

Evaluates an expression and routes execution to one of two branches. This is how you build if/else logic in a workflow.

Config	Description
Expression	The condition to evaluate, supports variable references from upstream handles
Operator	Comparison operator (equals, not equals, contains, greater than, less than, regex match, etc.)

Handles: One input (variables to evaluate), two outputs -- true and false. Connect downstream nodes to the appropriate output handle.

Loop

Iterates over a list or repeats a subgraph a fixed number of times. Each iteration passes the current item and index to the loop body.

Config	Description
Mode	`for-each` (iterate over a list) or `count` (repeat N times)
Source	The list variable to iterate over (for-each mode)
Count	Number of iterations (count mode)
Max parallel	How many iterations can run concurrently

Handles: One input (the list or context), one output (aggregated results from all iterations).

Transform

Applies a data transformation to reshape, filter, or map values between nodes. Use this when the output format of one node does not match the input format of the next.

Config	Description
Expression	A transformation expression or template
Output format	Expected output shape (JSON schema or freeform)

Handles: One input (source data), one output (transformed data).

Safety

Input Guardrails

Runs input safety checks (PII detection, prompt injection prevention, content filtering) on data flowing through the workflow. Produces two output handles so you can route safe and blocked content differently.

Config	Description
Checks	Which guardrail checks to enable (PII, prompt injection, content filter)
PII action	Block or redact when PII is detected
Sensitivity	Threshold for content filtering (0.0 to 1.0)

Handles: One input (content to check), two outputs -- pass (content is safe, continues to next step) and block (violation detected, routes to error handling or alternative path).

See Input Guardrails for details on each check.

Output Guardrails

Runs output safety checks (jailbreak detection, toxicity filtering, code execution prevention) on model responses before they reach downstream nodes or the end user.

Config	Description
Checks	Which output checks to enable (jailbreak, toxicity, code execution)
Sensitivity	Threshold for toxicity detection (0.0 to 1.0)

Handles: One input (model output to check), two outputs -- pass and block.

See Output Guardrails for details on each check.

Voice

TTS (Text-to-Speech)

Converts text to audio using a configured voice provider.

Config	Description
Provider	TTS provider and voice model
Voice	Voice selection or voice ID
Speed	Playback speed multiplier
Output format	Audio format (mp3, wav, opus)

Handles: One input (text content), one output (audio data and metadata).

STT (Speech-to-Text)

Transcribes audio input to text using a configured speech recognition provider.

Config	Description
Provider	STT provider and model
Language	Expected language for transcription
Timestamps	Whether to include word-level timestamps

Handles: One input (audio data), one output (transcribed text and metadata).

Voice Clone

Creates or uses a cloned voice profile for TTS synthesis. Combine with the TTS node for personalized voice output.

Config	Description
Source audio	Reference audio for voice cloning
Voice name	Label for the cloned voice profile
Provider	Voice cloning provider

Handles: One input (reference audio or voice ID), one output (cloned voice profile for use by TTS nodes).

Data

Memory Query

Queries the Everstack memory layer to retrieve stored context, facts, or embeddings. Use this to give downstream LLM or Agent nodes access to relevant stored knowledge.

Config	Description
Query	The search query, supports variable interpolation
Limit	Maximum number of results to return
Filter	Optional metadata filters to narrow results

Handles: One input (query parameters), one output (retrieved memory entries).

Memory Store

Writes data to the Everstack memory layer. Use this to persist outputs from earlier workflow steps for future retrieval.

Config	Description
Content	The content to store, supports variable interpolation
Metadata	Key-value metadata to attach to the memory entry

Handles: One input (content to store), one output (confirmation and stored entry ID).

Custom nodes

Beyond the built-in types, you can register custom node types by wrapping an Everstack function as a node. Custom nodes appear in the node palette alongside built-in types and follow the same handle and configuration conventions.

Building Workflows -- connecting nodes and configuring workflow logic.
Execution -- running and monitoring workflow executions.
Guardrails Overview -- deeper detail on safety checks.
Workflows API -- programmatic node and workflow management.

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