Inertia Rails Best Practices

A comprehensive guide to building high-quality Inertia.js applications with Ruby on Rails. This skill provides 50+ rules across 8 categories, prioritized by impact on application quality, performance, and maintainability.

When to Use This Skill

• Writing new Inertia Rails controllers or pages
• Reviewing existing Inertia Rails code
• Refactoring Rails applications to use Inertia
• Optimizing performance of Inertia applications
• Implementing authentication/authorization patterns
• Building forms with validation
• Setting up testing for Inertia responses

Categories Overview

#	Category	Priority	Impact
1	Server-Side Setup & Configuration	CRITICAL	Foundation for all Inertia functionality
2	Props & Data Management	CRITICAL	2-5× performance improvement, security
3	Forms & Validation	HIGH	User experience, data integrity
4	Navigation & Routing	HIGH	SPA experience, performance
5	Performance Optimization	MEDIUM-HIGH	30-70% faster page loads
6	Security	MEDIUM-HIGH	Protection against common vulnerabilities
7	Testing	MEDIUM	Code quality, maintainability
8	Advanced Patterns	MEDIUM	Scalability, complex use cases

Quick Reference

Server-Side Setup & Configuration (CRITICAL)

ID	Rule	Context
setup-01	Use the Rails generator for initial setup	New projects
setup-02	Configure asset versioning for cache busting	All projects
setup-03	Set up proper layout inheritance	Multi-layout apps
setup-04	Configure flash keys appropriately	Flash messaging
setup-05	Use environment variables for configuration	Deployment
setup-06	Set up default render behavior thoughtfully	Convention over configuration

Props & Data Management (CRITICAL)

ID	Rule	Context
props-01	Return only necessary data in props	All responses
props-02	Use shared data for global props	Auth, settings
props-03	Leverage lazy evaluation with lambdas	Expensive operations
props-04	Use deferred props for non-critical data	Performance
props-05	Implement partial reloads correctly	Data refreshing
props-06	Never expose sensitive data in props	Security
props-07	Use proper serialization with as_json	Data formatting
props-08	Implement deep merge when appropriate	Nested data
props-09	Use once props for stable data	Navigation performance

Forms & Validation (HIGH)

ID	Rule	Context
forms-01	Use useForm helper for complex forms	Programmatic control
forms-02	Use Form component for simple forms	Declarative forms
forms-03	Handle validation errors properly	User feedback
forms-04	Implement error bags for multiple forms	Multi-form pages
forms-05	Use redirect pattern after form submission	PRG pattern
forms-06	Handle file uploads correctly	Multipart forms
forms-07	Preserve form state on validation errors	User experience
forms-08	Use dotted notation for nested data	Complex forms

Navigation & Routing (HIGH)

ID	Rule	Context
nav-01	Use Link component for internal navigation	SPA behavior
nav-02	Use inertia_location for external redirects	External URLs
nav-03	Implement preserve-scroll appropriately	Scroll position
nav-04	Use preserve-state for component state	Form preservation
nav-05	Configure proper HTTP methods on links	RESTful actions
nav-06	Use the inertia route helper for static pages	Simple routes
nav-07	Handle 303 redirects correctly	POST/PUT/PATCH/DELETE

Performance Optimization (MEDIUM-HIGH)

ID	Rule	Context
perf-01	Implement code splitting with dynamic imports	Bundle size
perf-02	Use prefetching for likely navigation	Perceived performance
perf-03	Configure stale-while-revalidate caching	Data freshness
perf-04	Use polling only when necessary	Real-time updates
perf-05	Implement infinite scrolling with merge props	Large datasets
perf-06	Optimize progress indicators	User feedback
perf-07	Use async visits for non-blocking operations	Background tasks

Security (MEDIUM-HIGH)

ID	Rule	Context
sec-01	Implement authentication server-side	Auth patterns
sec-02	Pass authorization results as props	Permission checks
sec-03	Use history encryption for sensitive data	Browser history
sec-04	Rely on Rails CSRF protection	Form security
sec-05	Validate and sanitize all input server-side	Data validation
sec-06	Use strong parameters in controllers	Mass assignment

Testing (MEDIUM)

ID	Rule	Context
test-01	Use RSpec matchers for Inertia responses	RSpec testing
test-02	Use Minitest assertions for Inertia	Minitest testing
test-03	Test partial reloads and deferred props	Advanced features
test-04	Implement end-to-end tests with Capybara	Integration testing
test-05	Test flash messages after redirects	Flash testing
test-06	Verify component rendering	Response validation

Advanced Patterns (MEDIUM)

ID	Rule	Context
adv-01	Implement persistent layouts	State preservation
adv-02	Use custom component path resolvers	Non-standard paths
adv-03	Configure prop transformers	Data transformation
adv-04	Handle SSR appropriately	SEO requirements
adv-05	Implement view transitions	Modern animations
adv-06	Use scroll regions for complex layouts	Scroll management
adv-07	Handle events system effectively	Lifecycle hooks

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For detailed explanations, code examples, and implementation guidance for each rule, see AGENTS.md.