Flow Studio — Visual Workflow Builder

Studio & Canvas

Studio How-To

First-run orientation — workspace layout, toolbar, saving, publishing, version management.

Canvas Navigation

Pan, zoom, minimap, canvas controls, selection, keyboard shortcuts, snap-to-grid.

Node Palette

Browsing node categories, search, drag-to-canvas, node preview cards, favorites.

Connecting Nodes

Port types, drawing edges, conditional routing ports, port validation, disconnecting.

How To Execute

Run, test, and debug modes — input payload, trigger execution, watch results in real time.

SignalR Execution

Real-time execution streaming via SignalR — connection lifecycle, event types, reconnect.

Observer Panel

Live execution view — node status indicators, active node highlight, timeline visualization.

Execution Status Tab

Per-execution run history, status badges, duration, trigger type, restart/cancel actions.

Node List Tab

Flat list of all canvas nodes — filter by type, jump to node, bulk select, rename.

Logs Tab

Structured execution logs per node — log levels, filtering, search, correlation to execution id.

Node Inspector Tab

Selected node deep-dive — input data, output data, duration, errors, retry trace.

Node System

Node Templates

Saving node configs as templates, template library, applying templates to new nodes.

Bring Your Own Nodes

IExecutionNode contract, node metadata, registration, palette visibility, custom icons.

Backend Executor

ProcessEngine executor — how the backend runs nodes, context propagation, error handling.

Expression Engines

$json/$context expressions, JavaScript eval, JSONata, expression engine selection.

GuardRail Engines

Node-level GuardRail policies — engine types, evaluation order, block vs warn behavior.

Events & Access

Node Event Subscriptions

Subscribing to node lifecycle events — onStart, onComplete, onError, onSuspend handlers.

Event Bus & Events

Internal event bus — publishing custom events, cross-node communication, event schema.

Workflow Access

Role-based workflow permissions — view, edit, execute, publish access levels, team sharing.

Multi-Party Approval

Approval node with multiple actors — quorum rules, sequential vs parallel, timeout, delegate.

HIL — Human-in-the-Loop

HIL Overview

Human-in-the-Loop concepts — suspension model, WorkDesk inbox, actor assignment, resume.

HIL Suspension & Resume

Suspension lifecycle — SuspendExecution/ResumeExecution API, HIL token, callback patterns.

HIL Timeout

Timeout policies — escalation rules, auto-approve/reject, reminder notifications, SLA tracking.

Stores & State

Workflow Store

Zustand workflow store — nodes, edges, execution state, selection, canvas viewport state.

Designer Mode Store

Designer-mode Zustand slice — panel visibility, active tab, dirty flag, autosave state.

Observer Stores

Real-time execution Zustand stores — live node status, message queue, execution clock.

Undo/Redo History

History stack implementation — command pattern, snapshot diffing, max depth, merge strategy.

Node Observability

Per-node metrics — execution count, avg duration, error rate, P95 latency panels.

Log Streaming

Live log streaming to the Logs Tab via SignalR — buffering, flush intervals, level filtering.

Pinned Data

Node output pinning — pinned data panel, comparing across executions, test fixture reuse.

Execution Memory

Execution context store — per-execution variable bag, scoped reads, cross-node data access.

Variable Scoping

Scope hierarchy — global, workflow, loop, node local — read/write rules and shadowing.

Node Outputs

Output schema, named outputs, default output port, conditional output routing expressions.

Sub-Workflows

Calling nested workflows — input/output mapping, inline vs referenced, error propagation.

Node Capabilities

Capabilities Overview

14 capability types, INodeCapability interface, capability registration, ProcessSecurity grants.

Webhooks

Node capability for inbound webhooks — URL generation, payload routing, HMAC verification.

Business Services

Calling registered business services from nodes — service discovery, input/output contracts.

Forms

Atlas Forms capability — launching forms from nodes, response collection, pre-fill binding.

Widgets

App Studio widget capability — triggering widget actions from workflow nodes.

Messaging

Sending emails, SMS, push notifications, and EdgeStream messages from capability nodes.

Identity

Identity capability — user lookup, role checks, group membership, Passport SSO integration.

Entities

Entity CRUD capability — read, create, update, delete business entities from workflow nodes.

Datasources

DataOcean capability — querying SQL and app data sources with parameterized expressions.

Rules

Business rules capability — evaluating rule sets from nodes, rule input/output binding.

Processes

Launching child processes from capability nodes — fire-and-forget vs wait-for-completion.

DIDComm

Decentralized identifier messaging capability — DID resolution, signed messages, verifiable credentials.

MCP

Model Context Protocol capability — exposing node as MCP tool, agent-callable workflow triggers.

Workflow vs Server Nodes

Choosing between canvas-level workflow nodes and backend server-side execution nodes.