moai-domain-backend

name	moai-domain-backend
description	Backend development specialist covering API design, database integration, microservices architecture, and modern backend patterns. Use when user asks about API design, REST or GraphQL endpoints, server implementation, authentication, authorization, middleware, or backend service architecture. Do NOT use for database-specific schema design or query optimization (use moai-domain-database instead) or frontend implementation (use moai-domain-frontend instead).
license	Apache-2.0
compatibility	Designed for Claude Code
allowed-tools	Read Write Edit Bash(npm:*) Bash(npx:*) Bash(node:*) Bash(uv:*) Bash(pip:*) Bash(pytest:*) Bash(ruff:*) Bash(docker:*) Bash(curl:*) Bash(go:*) Bash(cargo:*) Grep Glob mcp__context7__resolve-library-id mcp__context7__get-library-docs
user-invocable	false
metadata	{"version":"1.0.0","category":"domain","status":"active","updated":"2026-01-11","modularized":"false","tags":"backend, api, database, microservices, architecture","author":"MoAI-ADK Team"}
triggers	{"keywords":["backend","API","server","authentication","authorization","REST","GraphQL","gRPC","microservices","database","endpoint","middleware","FastAPI","Express","Django","Flask","serverless","caching","Redis","PostgreSQL","MongoDB"]}

Backend Development Specialist

Quick Reference

Backend Development Mastery - Comprehensive backend development patterns covering API design, database integration, microservices, and modern architecture patterns.

Core Capabilities:

• API Design: REST, GraphQL, gRPC with OpenAPI 3.1
• Database Integration: PostgreSQL, MongoDB, Redis, caching strategies
• Microservices: Service mesh, distributed patterns, event-driven architecture
• Security: Authentication, authorization, OWASP compliance
• Performance: Caching, optimization, monitoring, scaling

When to Use:

• Backend API development and architecture
• Database design and optimization
• Microservices implementation
• Performance optimization and scaling
• Security integration for backend systems

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Implementation Guide

API Design Patterns

RESTful API Architecture:

Create a FastAPI application with authentication and response models. Define a Pydantic UserResponse model with id, email, and name fields. Implement list_users and create_user endpoints with HTTPBearer security dependency. The list endpoint returns a list of UserResponse objects, while the create endpoint accepts a UserCreate model and returns a single UserResponse.

GraphQL Implementation:

Use Strawberry to define GraphQL types. Create a User type with id, email, and name fields. Define a Query type with a users resolver that returns a list of User objects asynchronously. Generate the schema by passing the Query type to strawberry.Schema.

Database Integration Patterns

PostgreSQL with SQLAlchemy:

Define SQLAlchemy models using declarative_base. Create a User model with id as primary key, email as unique string, and name as string column. Configure the engine with connection pooling parameters including pool_size of 20, max_overflow of 30, and pool_pre_ping enabled for connection health checks.

MongoDB with Motor:

Create a UserService class that initializes with an AsyncIOMotorClient. Set up the database and users collection in the constructor. Create indexes for email (unique) and created_at fields. Implement create_user method that inserts a document and returns the inserted_id as string.

Microservices Architecture

Service Discovery with Consul:

Create a ServiceRegistry class that connects to Consul. Implement register_service method that registers a service with name, id, port, and health check endpoint. Implement discover_service method that queries healthy services and returns list of adddess:port strings.

Event-Driven Architecture:

Create an EventBus class using aio_pika for AMQP messaging. Implement connect method to establish connection and channel. Implement publish_event method that serializes event type and data as JSON and publishes to the default exchange with routing_key matching the event type.