n8n: nodes, expressions, CLI and settings in one place

01What you'll learn

This is a reference, not a step-by-step lesson — so section 03 is laid out as "task → answer" cards. You will find:

• The core concepts: workflow, node, item, execution, credentials, expression.
• Which nodes exist — triggers, actions, flow, AI and utility — and which are off by default in 2.x.
• How to write expressions and what to use in the Code node (JavaScript and native Python).
• How to install with Docker, how to manage it (logs, restart, updates) and which CLI commands are current.
• Which environment variables matter, and how to turn on queue mode.
• A short "symptom → cause → fix" table and where to read further.

02Before you start

What you need

• Docker with docker compose v2 for the install 🔒 local. On Windows the docs recommend WSL, with the project inside the WSL file system.
• For a local model: Ollama 🔒 local. For services such as Gmail — an account with the provider 🌐 global.
• Versions change almost every week. As of 01.10.2026 the docs list stable 2.41.4 and beta 2.42.1. For production use the stable one.

03Steps

For a reference the "steps" are cards by task. Take the one you need.

1. Core concepts

   Concept	What it is
   Workflow	A diagram of connected nodes that runs on a trigger or manually. Saved as JSON and can be exported/imported (see card 6).
   Node	The building block: receives items, processes them and passes them on.
   Item	A unit of data — one JSON object in the array a node passes on.
   Execution	One run of a workflow. Stored in the database; visible in the Executions tab. By default both successful and failed runs are saved, and old ones are deleted after 336 hours (card 9).
   Credentials	Encrypted access data. Encrypted with N8N_ENCRYPTION_KEY; one credential can serve many workflows.
   Expression	A dynamic value in a field, written in {{ }} with JavaScript. In an empty field press = to switch to expression mode.
   Sub-workflow	A workflow called from another through the Execute Sub-workflow node; it starts with an Execute Sub-workflow Trigger.
   Publishing	In 2.x the old "active/inactive" toggle is replaced by Publish / Unpublish. Production webhook URLs are registered when you publish.

2. Nodes: what to use for what

   Names follow the current docs. Marker: [off] — disabled by default in 2.x (turn on through NODES_EXCLUDE).

   Group	Node	What for
   Triggers	Webhook	HTTP request from an external system; has a test and a production URL
   	Schedule Trigger	On a schedule (cron or interval); the time zone is GENERIC_TIMEZONE
   	Email Trigger (IMAP)	New email in a mailbox
   	Gmail Trigger	New message in Gmail
   	Chat Trigger	Built-in chat — for AI agents
   	Execute Sub-workflow Trigger	Called from another workflow
   	Manual Trigger	Manual start for building and checking
   	Error Trigger · Local File Trigger [off]	Catches errors from another workflow · watches changes in the file system
   Actions	HTTP Request	Calls a REST API
   	Send Email	Sends mail through SMTP
   	Gmail	Reads and sends through Gmail
   	Read/Write File From Disk	File access on the machine running n8n
   	Postgres · Redis	Queries to PostgreSQL · work with Redis
   	SSH	Commands on a remote machine
   	Execute Command [off]	Commands on the machine running n8n (in Docker — inside the container)
   Flow	If · Switch	Branch by condition · by value
   	Merge	Merges streams
   	Loop Over Items (Split in Batches)	Processes items in batches; has loop and done outputs
   	Wait	A pause
   	Execute Sub-workflow	Calls another workflow
   	Respond to Webhook	Returns a response to the webhook caller
   	Stop and Error	Stops with your own error message (sent to the Error Trigger)
   AI	AI Agent	An agent with a model and tools; requires at least one tool (tool sub-node)
   	Basic LLM Chain	One LLM call: prompt → answer
   	Text Classifier · Sentiment Analysis · Information Extractor	Classifies · scores tone · pulls structured data out of text
   	Summarization Chain	Summarises long text
   	Ollama Chat Model	A local model through Ollama 🔒 local
   	Embeddings Ollama	Vector embeddings locally 🔒 local
   	Simple Memory	Short-term agent memory (formerly "Window Buffer Memory")
   	Qdrant Vector Store · Simple Vector Store	Vector store (external · in memory)
   	MCP Client Tool	Gives the agent tools from an MCP server
   Utility	Code	JavaScript or Python (card 5)
   	Edit Fields (Set)	Adds, renames, reorders fields without code
   	Filter · Sort · Limit	Filter by condition · sort · first N
   	Remove Duplicates	Removes repeated items
   	Aggregate · Summarize	Collects items into one · groups and calculates (sum, count)
   	HTML · Markdown	Extracts data from HTML with CSS selectors · converts HTML ↔ Markdown
   	Crypto	Hash and signature
   	Date & Time	Formats and calculates dates
   	Edit Image	Image processing

   💡

   You often do not need a loop

   Most nodes already process every item in the list. Loop Over Items is for cases where you need batches or a pause between requests (for example because of API limits). If you build a loop with reset, always add an end condition — otherwise the execution loops forever.

3. Expressions: reference

   Expression	Meaning
   {{ $json.field }}	A field of the current item
   {{ $json["field name"] }}	A field with a space in its name
   {{ $json.user.email }} · {{ $json.tags[0] }}	Nested field · first element of an array
   {{ $input.first().json.id }}	The first input item (also .last(), .all())
   {{ $input.all().length }}	Number of input items
   {{ $('Node Name').item.json.x }}	Data from a specific node for the matching item
   {{ $('Node Name').all() }}	All items that node output (also .first(), .last())
   {{ $prevNode.name }}	The name of the node the data came from
   {{ $workflow.name }} · {{ $execution.id }}	Workflow name · execution ID
   {{ $now }} · {{ $today }}	Now (Luxon DateTime, in the workflow time zone) · midnight today
   {{ $if(condition, if_true, if_false) }} · {{ $ifEmpty(value, fallback) }}	Short conditionals
   {{ $vars.name }} · {{ $fromAI('key') }}	Custom variable · a value the model fills in (in agent tools)

   expressionscopy

   // dates (Luxon)
   {{ $now.toFormat('dd.MM.yyyy') }}
   {{ $now.plus({ days: 7 }).toISO() }}
   {{ DateTime.fromISO($json.createdAt).toFormat('dd.MM.yyyy') }}
   
   // condition
   {{ $json.amount > 1000 ? 'VIP' : 'Standard' }}
   
   // text and numbers
   {{ $json.email.split('@')[0] }}
   {{ [$json.firstName, $json.lastName].join(' ') }}
   {{ Math.round($json.price * 1.2) }}
   
   // JSON for a request body
   {{ JSON.stringify($json) }}
   
   // fallback value
   {{ $json.name ?? 'Unknown' }}

   💡

   Expressions and the Code node are not the same thing

   Some helpers ($if(), $jmespath() and others) work only in the expression editor, not in the Code node. Methods tagged "Custom n8n functionality" in the reference may be missing there — use native Luxon (toFormat) and plain JavaScript. Note: plus()/minus() in expressions accept (number, unit) or an object, while native Luxon accepts only an object.

4. Data flow: Webhook, response and errors

   Webhook → process → respond. In the Webhook node set Respond to "Using 'Respond to Webhook' node", then place Respond to Webhook after the nodes whose data you return. It runs once, with the first item.

   Webhook → If (validation) → Code / Edit Fields → Postgres (write) → Respond to Webhook

   • The test URL works while you listen for an event (Listen for test event) and shows the data in the editor. Path: /webhook-test/<path>.
   • The production URL is registered when you publish the workflow; runs show up in Executions. Path: /webhook/<path>.
   • The largest request body is 16 MiB by default (N8N_PAYLOAD_SIZE_MAX).
   • An HTML response is wrapped in an <iframe> automatically (since 1.103.0) — scripts that reach for the top-level window will not work.

   Errors. Build a separate workflow that starts with an Error Trigger (for example "Error Handler"). In the main workflow: Options → Settings → Error workflow and pick it. The Error Trigger cannot be tested with a manual run — it fires only when an automatically started workflow fails. Stop and Error sends a custom message to it.

   Schedule → fetch → notify: Schedule Trigger → HTTP Request → Filter (new only) → Loop Over Items → Send Email. AI pipeline: Webhook or Email Trigger → Edit Fields (prepare the prompt) → AI Agent (with a model and a tool) → write.

5. The Code node: JavaScript and native Python

   Two modes: Run Once for All Items (the default — the code runs once for everything) and Run Once for Each Item. Inside, there is no file or HTTP access — use Read/Write File From Disk and HTTP Request.

   JavaScript · all itemscopy

   const out = [];
   for (const item of $input.all()) {
     out.push({
       json: {
         fullName: item.json.firstName + ' ' + item.json.lastName,
         processedAt: new Date().toISOString(),
       },
     });
   }
   return out;
   
   // filtering
   // return $input.all().filter(i => i.json.status === 'active');
   
   // everything in one item
   // return [{ json: { all: $input.all().map(i => i.json) } }];

   Python (native) · all itemscopy

   result = []
   for item in _items:
       data = item["json"]
       result.append({"json": {
           "id": data["id"],
           "total": data["price"] * data["qty"],
       }})
   return result

   🐍

   Python in 2.x: what changed

   The old Pyodide-based Python is removed. Native Python runs only on task runners in external mode (the separate n8nio/runners image), uses _items (all) and _item (one at a time), field access is only ["json"]["field"] (not item.json.field), and the other n8n built-in variables are not available. Modules beyond the standard library must be included in the runners image.
   ⚠️

   Environment variables from the Code node ⚠️

   The 2.0 notes say access to environment variables from the Code node is blocked by default (N8N_BLOCK_ENV_ACCESS_IN_NODE), but the variables table still shows a default of false. Do not rely on either: for secrets use credentials, not environment variables. $evaluateExpression() no longer works in the Code node — write the logic directly in JavaScript, or evaluate the expression in Edit Fields before the Code node.

6. Installing and managing with Docker

   Fastest (fresh install; read the script before running it; needs Docker with compose v2):

   bashcopy

   curl -fsSL https://get.n8n.io | sh

   Manually, for trying it out only (data lives in the n8n_data volume; the editor is at http://localhost:5678):

   bashcopy

   docker volume create n8n_data
   
   docker run -it --rm --name n8n -p 5678:5678 \
     -e GENERIC_TIMEZONE="<TIMEZONE>" \
     -e TZ="<TIMEZONE>" \
     -e N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS=true \
     -v n8n_data:/home/node/.n8n \
     docker.n8n.io/n8nio/n8n

   The first time, n8n asks you to create an owner account — that is how you log in (basic auth with N8N_BASIC_AUTH_* does not appear in the docs). N8N_RUNNERS_ENABLED is no longer needed from 2.0.

   A compose file template with PostgreSQL ⚠️ (assembled from the variables in the docs; not run by us — the official examples are in the n8n-io/n8n-hosting repository):

   compose.ymlcopy

   services:
     n8n:
       image: docker.n8n.io/n8nio/n8n:<VERSION>
       restart: unless-stopped
       ports:
         - "5678:5678"
       environment:
         - GENERIC_TIMEZONE=<TIMEZONE>
         - TZ=<TIMEZONE>
         - N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS=true
         - N8N_ENCRYPTION_KEY=<SECRET>
         - N8N_HOST=<YOUR-DOMAIN>
         - N8N_PROTOCOL=https
         - N8N_WEBHOOK_URL=https://<YOUR-DOMAIN>/
         - DB_TYPE=postgresdb
         - DB_POSTGRESDB_HOST=<DB-HOST>
         - DB_POSTGRESDB_DATABASE=<DATABASE>
         - DB_POSTGRESDB_USER=<USER>
         - DB_POSTGRESDB_PASSWORD=<SECRET>
       volumes:
         - n8n_data:/home/node/.n8n
   volumes:
     n8n_data:

   Even with PostgreSQL keep the /home/node/.n8n volume — keys, logs and other important files are there. Without N8N_ENCRYPTION_KEY n8n generates a key itself on first start; if you set one, keep it somewhere safe — without it saved credentials cannot be read.

   bash · managingcopy

   docker ps
   docker logs -f --tail=100 n8n
   docker restart n8n
   docker stats n8n
   
   # update (compose)
   docker compose pull
   docker compose down
   docker compose up -d
   
   # update (docker run): pull the image, stop and remove the old container, start again
   docker pull docker.n8n.io/n8nio/n8n

7. CLI and REST API

   The Server CLI runs on the same machine as n8n and touches the database directly. In Docker: docker exec -u node -it <container> n8n <command>.

   bash · Server CLIcopy

   n8n execute --id <ID>
   
   # publishing (replaces update:workflow since 2.0)
   n8n publish:workflow --id=<ID>
   n8n unpublish:workflow --id=<ID>
   
   # backup of workflows and credentials
   n8n export:workflow --backup --output=backups/latest/
   n8n export:credentials --backup --output=backups/latest/
   
   # restore
   n8n import:workflow --separate --input=backups/latest/
   n8n import:credentials --separate --input=backups/latest/
   
   # security check
   n8n audit

   • publish:workflow / unpublish:workflow touch the database — if n8n is running, the change takes effect after a restart. There is no --all for publishing (on purpose), but there is one for unpublish.
   • update:workflow is deprecated since 2.0. We could not find n8n list:workflow in the current docs — do not rely on it.
   • export:credentials --decrypted writes secrets as plain text — use it only for a deliberate transfer and then delete the file securely.
   • Imported workflows stay inactive by default (--activeState=false).
   • --backup covers workflows and credentials only; a full instance backup has more parts — see "Back up and restore" in the docs.

   REST API (from another machine): a key from Settings → n8n API, sent in the X-N8N-API-KEY header. The API is not available during the n8n Cloud free trial.

   bash · REST and healthcopy

   curl 'https://<YOUR-N8N>/api/v1/workflows?active=true' \
     -H 'accept: application/json' \
     -H 'X-N8N-API-KEY: <API-KEY>'
   
   # call a production webhook
   curl -X POST 'https://<YOUR-N8N>/webhook/<PATH>' \
     -H 'Content-Type: application/json' \
     -d '{"key": "value"}'
   
   # liveness check
   curl -sf 'https://<YOUR-N8N>/healthz'

8. Keyboard shortcuts (per the docs)

   Group	Shortcuts
   Workflow	Ctrl/Cmd+S save · Ctrl/Cmd+Z undo · Ctrl/Cmd+Shift+Z redo · Ctrl/Cmd+Enter execute · Ctrl/Cmd+Alt+N new · Ctrl/Cmd+O open
   Canvas	Space+drag or middle button — pan · +/- zoom · 0 reset zoom · 1 fit the workflow · Ctrl/Cmd+wheel zoom
   Nodes	N node panel · Ctrl/Cmd+A all · Ctrl/Cmd+C/X/V · F2 rename · P pin data · D deactivate · Delete delete · Shift+S sticky note
   Other	Ctrl/Cmd+K command bar · Escape closes the node panel

   Running the "whole workflow" and "this node only" are separate buttons in the editor; pinning data freezes a node's output while you build.

9. Environment variables and queue mode

   Variable	Meaning
   N8N_HOST · N8N_PORT · N8N_PROTOCOL	The host name, port (5678) and protocol (http/https) used to reach n8n
   N8N_WEBHOOK_URL	Base URL of webhooks behind a reverse proxy; must be reachable from outside. WEBHOOK_URL is a deprecated alias (since 2.35.0)
   N8N_EDITOR_BASE_URL · N8N_PROXY_HOPS	Public editor URL (for emails and SSO) · how many reverse proxies sit in front
   GENERIC_TIMEZONE · TZ	n8n's time zone (default America/New_York!) — matters for schedules · container clock
   N8N_ENCRYPTION_KEY	Key that encrypts credentials; generated automatically by default. Keep it; in queue mode it is the same everywhere
   DB_TYPE	postgresdb for production · SQLite by default. MySQL/MariaDB are not supported since 2.0
   N8N_LOG_LEVEL	info (default) · warn · error · debug
   EXECUTIONS_DATA_PRUNE · EXECUTIONS_DATA_MAX_AGE	Clean up old executions (on by default) · age in hours (default 336 = 14 days)
   EXECUTIONS_DATA_SAVE_ON_SUCCESS / _ON_ERROR	all or none; everything is saved by default
   N8N_METRICS	true turns on the /metrics endpoint (off by default)
   N8N_PAYLOAD_SIZE_MAX	Largest request body in MiB (16)
   N8N_DISABLE_UI	true disables the editor
   NODES_EXCLUDE	Which nodes are disabled; Execute Command and Local File Trigger are there by default
   N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS	true sets 0600 permissions on the settings file

   Queue mode (many workers): the main instance receives triggers and webhooks and puts executions in a queue in Redis; workers pick them up and run them.

   1. Redis (QUEUE_BULL_REDIS_HOST, QUEUE_BULL_REDIS_PORT, default 6379) and PostgreSQL — SQLite with queue mode is not recommended.
   2. EXECUTIONS_MODE=queue on the main instance and on every worker; the same N8N_ENCRYPTION_KEY everywhere.
   3. Worker: n8n worker (--concurrency=N, default 10; 5 or more recommended). Optional: separate webhook processes with n8n webhook.
   4. Binary data in the file system is not supported in queue mode — use external storage (S3).
   🛡️

   Network protection — a general rule

   Run n8n behind a reverse proxy with HTTPS; only the editor entrance and webhooks should be visible from outside — not the database, Redis or workers. Addresses and ports of a specific installation do not belong on pages like this one.

10. Quick diagnostics: symptom → cause → fix

    Symptom	Likely cause	Fix
    The production webhook does not respond	The workflow is not published (only the test URL works)	Publish it; use /webhook/…, not /webhook-test/…
    The webhook shows a wrong address behind a proxy	n8n does not know its external address	Set N8N_WEBHOOK_URL (and N8N_PROXY_HOPS)
    The schedule fires at the wrong hour	The zone is the default America/New_York	Set GENERIC_TIMEZONE (and TZ)
    After a move, credentials cannot be read	A different N8N_ENCRYPTION_KEY	Restore the old key; in queue mode — the same on all instances
    No Execute Command or Local File Trigger node	Disabled by default since 2.0	Change NODES_EXCLUDE — only if you understand the risk
    Python in the Code node does not start or complains about item.json	Native Python needs task runners in external mode and bracket access	Run the n8nio/runners image; use _items and item["json"]
    $evaluateExpression() in Code returns null	Not supported with task runners	Write the logic in JavaScript or evaluate the expression in Edit Fields before Code
    The error workflow does not fire in a manual test	The Error Trigger runs only from an automatic execution	Test through a trigger or a published workflow
    CLI publishing has no effect	n8n is running while the CLI writes to the database	Restart n8n
    A webhook request is rejected for size	Over 16 MiB	Raise N8N_PAYLOAD_SIZE_MAX (with more memory and CPU)
    The database keeps growing	All executions are saved	Keep EXECUTIONS_DATA_PRUNE on and lower EXECUTIONS_DATA_MAX_AGE

04Check

Checklist

• You know you are on the 2.x line: publish instead of activate, native Python, login with an owner account.
• N8N_ENCRYPTION_KEY is stored somewhere safe and is the same on all workers.
• GENERIC_TIMEZONE is set before you rely on schedules.
• Production webhooks work only after publishing; test ones are for building.
• Before queue mode you have PostgreSQL and Redis.
• Secrets are in credentials — not in fields, expressions or pages.

Quiz

05What's next

06Sources

1. n8n: one-line setup · install with Docker · with Docker Compose — image, volume, versions, n8n 3.0.
2. Server CLI and REST API authentication — publish:workflow, export/import, X-N8N-API-KEY.
3. What changes in 2.0 — publishing, native Python, disabled nodes, task runners.
4. Environment variables — the Deployment, Endpoints, Executions, Queue mode, Security and Timezone sections.
5. Queue mode — Redis, workers, the encryption key.
6. Expression reference and the Code node.
7. AI Agent · Webhook · Respond to Webhook · Error Trigger.
8. Keyboard shortcuts.
9. GitHub: n8n-io/n8n — quick start and the compose definition.