GuideIntermediate
JavaScript in the n8n Code Node
Learn to write JavaScript inside n8n's Code node with confidence: read and transform items, reference data from other nodes, call external APIs with the right pattern, debug with the replay engine, and decide with judgment when code beats the visual canvas. This guide doesn't teach JavaScript as a general-purpose language — it teaches the subset you actually use inside the Code node, starting from zero if you've never programmed before. It closes with a production-grade workflow: ingesting data through a paginated API, transforming it with `map`/`filter`/`reduce`, defensive code, idempotency, and enrichment with an LLM — documented and ready to defend in an interview or portfolio.
- 48
- lessons
- 6
- modules
- English · Spanish
- available in
- Yes
- certificate
- Free
- access
Outcomes
What you'll be able to do
- Recognize when n8n's visual canvas falls short and you need to code, and what a Code node script must return
- Master the essential JavaScript for manipulating data: values, objects, arrays, `map`/`filter`/`reduce`, strings, functions, and control flow
- Understand n8n's item model: reading input with `$input`, the current item with `$json`, and referencing other nodes
- Tell expressions (one-line code) apart from the Code node, including dates with Luxon and queries with JMESPath
- Apply the correct pattern for calling APIs from a Code node workflow: Code → HTTP Request → Code, without exposing credentials in code
- Handle pagination, rate limits, and response parsing, including preparing prompts and parsing an LLM's output
- Debug with n8n's replay engine, read and throw your own errors, and write defensive code with null and type checks
- Design idempotent, documented input/output contracts ready for production
Before you start
What you need to bring
It's for you if...
- People who already use n8n with visual nodes and simple expressions and need to make the jump to coding inside the Code node
- Automation builders who want to stop being "workflow assemblers" and become the owner of a system that defines its own data model
- n8n freelancers or consultants who need to defend code-driven workflows to a client or in a technical interview
- Anyone with no prior programming experience who wants to learn applied JavaScript, not a general-purpose language course
Requirements and materials
- n8n fundamentals and data-handling guides completed (or equivalent mastery of the canvas, items, and expressions at the visual level)
- No prior programming experience required: the JavaScript you need is taught from scratch in Module 2
- A self-hosted Community n8n instance ($0) is recommended to practice the Code node and the debugging engine
Content
The syllabus, module by module
Open any of them to see its lessons.
- 1. Introduction: the role really does require code
- 2. The no-code myth and when you have to program
- 3. Anatomy of the Code node in n8n 2.0
- 4. JavaScript or Python in the Code node
- 5. Run once for all items or run once per item
- 6. What your code must return
- 7. Anatomy of a Code node script
- 8. Mini-project: your first Code node
- 1. Introduction: the Code node doesn't call APIs, and that's fine
- 2. Why the Code node can't call APIs
- 3. The Code → HTTP Request → Code pattern
- 4. Credentials never live in the code
- 5. Pagination and rate limits
- 6. Parsing and shaping responses
- 7. Preparing prompts and parsing LLM output
- 8. Mini-project: enriching orders via API
Common questions
What people usually ask
No limit. It's a free guide: come in whenever you like, as often as you like.
No. Modules run from easier to harder, but you can jump to the one you need. Progress is saved per lesson.
Whatever is needed is listed under “What you need to bring”, above. If nothing is listed there, you can start from zero.
In the Club's WhatsApp group, and every two weeks there's a live with an instructor where questions get worked through.
Yes. It's issued automatically once you finish every lesson, with a verifiable code you can share on LinkedIn.
Start whenever you like
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