commercetools Merchant Center Customization Development
Progressive loading — only load what you need:
- Building a Custom Application? Load
references/custom-applications.md
- Building a Custom View? Load
references/custom-views.md
- Working with data fetching or external API proxying? Load
references/ui-data-fetching.md
- Working with forms, routing, or UI Kit components? Load
references/ui-forms-components.md
- Deploying or testing? Load
references/deployment.md
CRITICAL Priority -- Architectural Decisions
| Pattern | File | Impact |
|---|
| Custom Application vs Custom View | references/custom-applications.md | Wrong choice means rebuilding from scratch. Applications are full pages; Views are embedded panels. |
| Application Shell & Entry Point Config | references/custom-applications.md | Misconfigured entryPointUriPath or cloudIdentifier blocks all development. Reserved paths silently fail. |
| OAuth Scopes & Permission Model | references/custom-applications.md | Missing scopes cause 403 errors in production. Over-scoping violates least privilege. Team assignment is required. |
HIGH Priority -- Development Patterns
MEDIUM Priority -- Deployment & Operations
| Pattern | File | Impact |
|---|
| Deployment to Vercel / Netlify | references/deployment.md | Missing SPA rewrites cause 404s. Wrong build command skips MC compilation. |
| Deployment to commercetools Connect | references/deployment.md | connect.yaml misconfiguration blocks deployment. APPLICATION_URL is auto-provided. |
| Application Registration & States | references/deployment.md | Forgetting to move from Draft to Ready means the app cannot be installed. |
| Testing Custom Applications | references/deployment.md | MC-specific test utilities required for permission and context mocking. |
Common Anti-Patterns (Quick Reference)
Decision Flowchart: Custom Application or Custom View?
Does the functionality need its own page and main menu entry?
YES --> Custom Application
NO --> Continue
Does the functionality enhance an EXISTING built-in MC page?
(e.g., extra details on an Order, Customer, or Product page)
YES --> Custom View
NO --> Continue
Does the functionality require complex multi-page navigation?
(e.g., list page, detail page, create/edit forms)
YES --> Custom Application
NO --> Continue
Is the functionality a simple panel showing contextual info or actions?
(e.g., order tracking, loyalty points, quick edits)
YES --> Custom View (narrow or extended panel)
NO --> Custom Application (default choice for standalone features)
MCP Complement
Use this skill to DESIGN and STRUCTURE your MC extension, then use the Developer MCP for MC SDK docs and the Commerce MCP for CRUD operations.