backend-dev-guidelines

name	backend-dev-guidelines
description	Shared backend guide for Langfuse's Next.js, tRPC, BullMQ, and TypeScript monorepo. Use when creating or reviewing tRPC routers, public REST endpoints, BullMQ queue processors, backend services, middleware, Prisma or ClickHouse data access, OpenTelemetry instrumentation, Zod validation, env configuration, or backend tests across web, worker, or packages/shared.

Backend Development Guidelines

Use this skill for backend and API work across web/, worker/, and packages/shared/.

When to Apply

• Creating or modifying tRPC routers and procedures
• Creating or modifying public API endpoints
• Creating or modifying queue processors, producers, or queue-backed workflows
• Building or refactoring backend services and repositories
• Working on backend auth, middleware, validation, or observability
• Updating Prisma or ClickHouse access patterns
• Adding or fixing backend tests

How to Read This Skill

• Start with AGENTS.md when the task spans multiple backend areas or you need the end-to-end checklists.
• Read only the specific reference file that matches the work when the scope is narrower.

Reference Map

Topic	Read this when	File
Architecture and package boundaries	You need the web/worker/shared split, request flow, or queue lifecycle	references/architecture-overview.md
Routing and controllers	You are writing tRPC procedures, public API routes, or queue entrypoints	references/routing-and-controllers.md
Middleware and auth	You are changing request auth, permissions, or middleware composition	references/middleware-guide.md
Services and repositories	You are placing business logic, repository code, or DI patterns	references/services-and-repositories.md
Database access	You are touching Prisma, ClickHouse, tenant filters, or query patterns	references/database-patterns.md
Configuration	You are adding env vars, startup config, or runtime toggles	references/configuration.md
Testing	You are adding or updating backend tests	references/testing-guide.md

Full Compiled Guide

Read AGENTS.md for the complete backend guide with checklists, directory conventions, imports, architecture, and cross-cutting practices.