Core concepts

Nodes and triggers#

A node is one step in a workflow. It receives data, does one thing with it, and passes the result on. n8n ships with hundreds of nodes for specific services, plus general-purpose ones: HTTP Request for any REST API, Code for JavaScript or Python, and the flow-logic nodes covered in Flow logic.

A trigger node is the first node in a workflow and decides when it runs. The common triggers are:

• Schedule — run on an interval or a cron expression.
• Webhook — run when an HTTP request arrives, which turns the workflow into an API endpoint.
• App triggers — run when something happens in a connected service, such as a new row or a new message.
• Manual — run when you press Execute Workflow in the editor. Useful while building; not for production.

A workflow without a trigger node can only run manually.

Items and executions#

Data moves between nodes as items — a list of JSON objects. When a node receives five items, it usually runs its operation five times, once per item, and passes five results forward. This is why you rarely need an explicit loop: iteration is the default.

An execution is one run of a workflow from start to finish. Executions are what your plan is measured in, and what you inspect when something goes wrong: each one is stored with the data that passed through every node, so you can open a failed run and see the exact payload that broke it.

How long executions are kept depends on your plan — from 7 days on Starter to unlimited on Enterprise.

Credentials#

A credential holds the secret for a service — an API key, an OAuth token, a database password. Credentials are stored encrypted and separately from workflows, which has two consequences worth knowing:

• One credential can be reused by many workflows and many nodes.
• You can share a workflow, including exporting its JSON, without leaking the secret inside it.

On paid tiers, credentials can be shared with specific projects rather than the whole instance. See Security and credentials.

Expressions#

An expression pulls a value from earlier in the workflow instead of hardcoding it. Anywhere a field accepts a fixed value, it also accepts an expression, written in double curly braces:

{{ $json.email }}
{{ $json.first_name + ' ' + $json.last_name }}
{{ $now.minus(7, 'days').toISO() }}

The variables you reach for most often:

When an expression grows past a line or two, move the logic into a Code node — it is easier to read and easier to debug.

Related#

• Build your first workflow — see all four concepts in one tutorial
• Work with data — expressions and data reshaping in depth
• Glossary — every term in one place