backend-patterns

Backend entity patterns - services with DI, Drizzle schemas (3-file pattern), ORPC routers, TypeIDs, neverthrow. Use when creating services, schemas, routers, or new entities.

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/development/backend-patterns

SKILL.md

Backend Patterns

Use this skill when building backend features. Follow these patterns for consistency.

Project Setup

Replace these placeholders for your project:

@project/ → your package scope (e.g., @myapp/)
packages/ paths follow standard monorepo layout

Expected packages:

@project/db - Drizzle database client, DB_SCHEMA export
@project/shared - TypeIDs, constants, shared schemas
@project/logger - Pino logger wrapper

Quick Reference

Entity Type	Pattern	Files to Create/Modify
Service	Factory function with deps, neverthrow	`packages/api/src/services/xxx-service.ts`, `context.ts`
Schema	3-file pattern	`.db.ts`, `.zod.ts`, `.relations.ts` in `packages/db/src/schema/`
Router	ORPC procedures, Result→Error mapping	`packages/api/src/routers/xxx-router.ts`, `routers.ts`
TypeID	Prefixed ID	`packages/shared/src/typeid.schema.ts`

Key Conventions

db.query preferred over db.select for simple lookups (see service.md)
neverthrow for service error handling, .match() in routers (see router.md)
Zod enums with as const + z.enum() pattern (see schema.md)

Pattern Details

For service creation, see service.md
For schema creation, see schema.md
For router creation, see router.md

Workflow: Adding a New Entity

Add TypeID prefix to packages/shared/src/typeid.schema.ts
Create schema files in packages/db/src/schema/{domain}/
Create service in packages/api/src/services/
Add to context in packages/api/src/context.ts
Create router in packages/api/src/routers/
Export router in packages/api/src/routers/routers.ts
Run bun run db:generate if schema changed