N8n Development

n8n Development Skill

This skill provides comprehensive guidance for developing, testing, and maintaining n8n webhook workflows integrated with Python services. It includes patterns for building composable workflows, template development, test-driven development practices, and complete development workflows.

When to Use This Skill

Apply this skill when:

• Building new n8n webhook workflows
• Integrating n8n workflows with Python services
• Writing tests for workflow integrations
• Creating reusable workflow templates
• Debugging workflow execution issues
• Setting up development environments for n8n projects
• Following best practices for async patterns and error handling

Core Development Principles

Test-Driven Development

1. Start with a failing test to define expected behavior
2. Implement minimal code to make the test pass
3. Refactor while keeping tests green
4. Run tests with uv run pytest

Workflow Development Process

1. Design the webhook contract (request/response schema)
2. Implement in n8n with error handling
3. Export JSON to nathan/workflows/[category]/
4. Add to registry (workflow_registry.yaml)
5. Write integration tests in tests/workflows/[category]/
6. Document with usage examples

Template Development

1. Define variables using ${VAR_NAME} syntax
2. Add validation via schema in template frontmatter
3. Test rendering using CLI
4. Document with usage examples in comments

Essential Commands

# Core development
uv sync                                    # Install dependencies
uv run pytest                              # Run tests
uv run pytest --cov=nathan --cov-report=term-missing  # With coverage
uvx ruff check .                           # Lint
uvx ruff format .                          # Format

# n8n development
docker compose -f docker-compose.n8n.yml up -d  # Run n8n locally
uv run python -m nathan.scripts.n8n_workflow_registry --help  # Registry CLI
uv run python -m nathan.templating --help  # Template CLI

Testing Guidelines

Test structure should mirror source in tests/ directory with descriptive naming (test_trigger_workflow_with_valid_parameters). Use pytest fixtures for shared setup and mock external dependencies. Target 80%+ test coverage.

Validation and Schemas

Use Pydantic models for API requests/responses and SQLModel for database models. Implement input validation at boundaries (API endpoints, CLI arguments) with clear, actionable error messages.

Async Patterns

Use httpx for all HTTP calls with proper timeout handling. Always use try/except for HTTP calls and async with context managers for HTTP clients. Use asyncio.gather() for parallel operations.

Reference Documents

Load these reference files when needed for specific tasks:

• Common Patterns: Load references/common_patterns.md for workflow registry, template rendering, and error handling code examples
• Code Review: Load references/review_checklist.md before submitting code for review
• CLI Commands: Load references/cli_commands.md for n8n command-line operations (export, import, execute workflows)
• REST API: Load references/rest_api.md for n8n REST API endpoints and Python client examples
• Workflow JSON: Load references/workflow_json_structure.md for understanding and building n8n workflow JSON files

Commit Guidelines

Follow conventional commits format:

• feat: for new features
• fix: for bug fixes
• docs: for documentation changes
• test: for test additions/changes
• refactor: for code refactoring

Make atomic commits (one logical change per commit), test before committing, and include documentation updates with code changes.