Django Development Best Practices

Django Development Best Practices

Comprehensive performance and development optimization guide for Django applications, containing 60+ rules across 9 categories, prioritized by impact to guide automated development and code generation.

When to Apply

Reference these guidelines when:

• Building new Django applications or features
• Writing models, views, templates, or forms
• Implementing authentication and security
• Optimizing database queries and performance
• Setting up testing and deployment
• Reviewing Django code for best practices
• Customizing admin interfaces and URL configurations
• Implementing caching strategies and middleware
• Working with static files and media uploads
• Understanding Django signals and advanced patterns

Rule Categories by Priority

Quick Reference

1. Security & Authentication (CRITICAL)

• security-csrf-protection: Always enable CSRF protection for forms
• security-sql-injection: Use parameterized queries and ORM methods
• security-xss-prevention: Escape user input in templates
• security-https-only: Force HTTPS in production
• security-password-hashing: Use Django's password hashing
• security-session-security: Secure session configuration
• signing-cryptography: Secure data signing for integrity and tamper prevention

2. Database & Models (CRITICAL)

• db-migration-safety: Never modify migrations manually
• db-indexes-strategy: Add indexes for frequently queried fields
• db-foreign-key-protection: Use on_delete appropriately
• db-n-plus-one-queries: Use select_related and prefetch_related
• db-constraints-validation: Use model and database constraints
• db-transaction-management: Wrap related operations in transactions

3. Views & URLs (HIGH)

• views-function-vs-class: Choose appropriate view type
• views-http-methods: Handle HTTP methods correctly
• views-error-handling: Implement proper error responses
• views-pagination: Use Django's pagination for large datasets
• views-caching-strategy: Implement appropriate caching layers
• views-api-serialization: Use proper serialization for APIs
• exceptions-error-handling: Proper exception handling and error views
• http-request-response: Handling HttpRequest and HttpResponse objects

4. Forms (HIGH)

• forms-modelform-usage: Prefer ModelForm for model-backed forms
• forms-validation-logic: Implement custom validation methods
• forms-security-cleaning: Always clean and validate form data
• forms-error-display: Provide clear error messages to users
• forms-file-handling: Handle file uploads securely
• forms-formsets-usage: Use formsets for multiple related forms
• validators: Built-in and custom validators for data validation

5. Templates (MEDIUM-HIGH)

• templates-inheritance-pattern: Use template inheritance for DRY templates
• templates-context-data: Keep templates simple, logic in views
• templates-filters-security: Use safe filters carefully
• templates-static-files: Manage static files properly
• templates-internationalization: Implement i18n support
• templates-performance: Minimize template rendering overhead

6. Authentication & Authorization (MEDIUM-HIGH)

• auth-user-management: Implement secure user authentication
• auth-permissions-groups: Use Django's permission system
• auth-custom-user-model: Extend user model when needed
• auth-session-security: Secure session handling
• auth-password-security: Password management best practices
• auth-social-auth: Third-party authentication integration

7. URLs & Admin (MEDIUM-HIGH)

• urls-configuration-patterns: Organize URL patterns effectively
• urls-reverse-urls: Use reverse() for URL generation
• urls-namespaces: Implement URL namespaces and app names
• admin-customization: Customize Django admin interface
• admin-actions-filters: Add custom admin actions and filters
• admin-security: Secure admin interface access

6. Testing (MEDIUM-HIGH)

• testing-unit-vs-integration: Write appropriate test types
• testing-fixtures-usage: Use fixtures for test data
• testing-mocking-strategy: Mock external dependencies
• testing-coverage-goals: Maintain high test coverage
• testing-django-testcase: Use Django's TestCase subclasses
• testing-factory-pattern: Use factories for complex test data

7. Performance (MEDIUM)

• perf-query-optimization: Optimize database queries
• perf-caching-strategy: Implement multiple caching layers
• perf-static-file-optimization: Optimize static file serving
• perf-database-indexing: Use appropriate database indexes
• perf-middleware-optimization: Order middleware efficiently
• perf-async-support: Use async views where appropriate
• async-views-tasks: Asynchronous operations and background tasks
• files-media-handling: File uploads and storage management

8. Deployment (MEDIUM)

• deploy-environment-separation: Separate development and production
• deploy-secret-management: Securely manage secrets and keys
• deploy-static-files-serving: Configure static file serving
• deploy-database-configuration: Optimize database settings
• deploy-monitoring-setup: Implement logging and monitoring
• deploy-backup-strategy: Implement data backup procedures
• settings-management: Django settings configuration and environment variables

9. Advanced Patterns (LOW)

• advanced-signals-usage: Use signals appropriately
• advanced-middleware-custom: Implement custom middleware
• advanced-model-managers: Create custom model managers
• advanced-generic-views: Extend generic views properly
• advanced-admin-customization: Customize admin interface
• advanced-internationalization: Implement advanced i18n features
• middleware-basics: Middleware concepts and custom middleware creation
• unicode-text-handling: Encoding and text processing for international apps

How to Use

Read individual rule files for detailed explanations and code examples:

rules/security-csrf-protection.md
rules/db-migration-safety.md
rules/views-function-vs-class.md
rules/auth-user-management.md
rules/admin-customization.md
rules/caching-strategy.md

Each rule file contains:

• Impact level and category
• Problem description
• Solution with code examples
• Common mistakes to avoid
• When to apply the rule

Reference Documentation

Detailed guides for complex topics:

references/workflows.md          # Development workflow patterns
references/middleware-signals.md  # Middleware and signals implementation
references/deployment-static.md   # Static files, media, and deployment

Full Compiled Document

For the complete Django best practices guide with all rules expanded: AGENTS.md