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Core Concepts

Understanding these core concepts will help you get the most out of FlowStack.

Flows (Automations)​

A flow is an automation — a series of steps that execute in sequence when triggered. Flows are the fundamental building block of FlowStack.

Every flow has:

  • A trigger — The event that starts the flow (schedule, webhook, app event, or manual)
  • One or more actions — The steps the flow performs (send email, update database, call API, etc.)
  • A status — Active (running automatically) or Inactive (paused)

Engines​

FlowStack provides two automation engines, each optimized for different use cases:

Flow Builder (ActivePieces Engine)​

  • Clean, intuitive visual interface
  • 687+ pre-built pieces (integrations)
  • Best for: straightforward automations, quick prototyping, non-technical users
  • Strengths: deep OAuth support, simple branching, built-in testing

Workflow Builder (n8n Engine)​

  • Advanced visual editor with data transformation
  • 880+ node types including 130+ AI/LangChain nodes
  • Best for: complex multi-branch workflows, data processing, AI pipelines
  • Strengths: Code node (JavaScript/Python), advanced expressions, sub-workflows

You choose the engine when creating each automation. Both engines share the same dashboard, connections list, and monitoring tools.

Runs (Executions)​

A run is a single execution of a flow. Every time a flow is triggered, it creates a run.

Each run records:

  • Status — Succeeded, Failed, or Running
  • Duration — How long the execution took
  • Trigger type — What started it (schedule, webhook, manual, etc.)
  • Step-by-step output — The input and output of every action in the flow
  • Timestamps — When it started and finished

View runs from Dashboard → Automations → View Runs or from inside the builder's Runs tab.

Connections​

A connection is an authenticated link between FlowStack and an external service. Connections are created once and reused across multiple flows.

FlowStack supports three connection methods:

  • OAuth 2.0 — One-click popup authorization (Google, Slack, GitHub, etc.)
  • API Key — Paste your API key from the service's settings
  • Basic Auth — Username and password

Connections are encrypted at rest (AES-256) and in transit (TLS 1.3). Tokens are automatically refreshed when they expire.

Pieces & Nodes​

  • Pieces (Flow Builder) — Pre-built integration modules. Each piece provides triggers and actions for a specific app (e.g., the Gmail piece has triggers like "New Email" and actions like "Send Email").
  • Nodes (Workflow Builder) — Equivalent concept in the n8n engine. Nodes can be triggers, actions, or utility operations (IF, Switch, Merge, Code, etc.).

Projects​

A project is an isolated workspace within your FlowStack account. Projects provide:

  • Separate flow lists and run histories
  • Independent connection pools
  • Per-project API keys
  • Team member access control

On Free and Pro plans, you have one project. Team and Enterprise plans support multiple projects.

Triggers​

Triggers determine when a flow runs:

TriggerDescription
ScheduleCron-based (every minute, hourly, daily, custom cron expression)
WebhookHTTP endpoint that starts the flow when called
App EventFires when something happens in a connected app (new row, new message, etc.)
ManualRun on-demand from the dashboard or API

Actions​

Actions are the steps your flow performs after it's triggered. Examples:

  • Send an email via Gmail
  • Post a message to Slack
  • Create a row in Google Sheets
  • Call an HTTP endpoint
  • Run custom JavaScript or Python code
  • Query a FlowStack Table
  • Branch based on conditions