backend-development

Included with Lifetime

$97 forever

Backend API design, database architecture, microservices patterns, and test-driven development. Use for designing APIs, database schemas, or backend system architecture.

Design

What this skill does


# Backend Development

## API Design

### RESTful Conventions
```
GET    /users          # List users
POST   /users          # Create user
GET    /users/:id      # Get user
PUT    /users/:id      # Update user (full)
PATCH  /users/:id      # Update user (partial)
DELETE /users/:id      # Delete user

GET    /users/:id/posts  # List user's posts
POST   /users/:id/posts  # Create post for user
```

### Response Format
```json
{
  "data": { ... },
  "meta": {
    "page": 1,
    "per_page": 20,
    "total": 100
  }
}
```

### Error Format
```json
{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid input",
    "details": [
      { "field": "email", "message": "Invalid format" }
    ]
  }
}
```

## Database Patterns

### Schema Design
```sql
-- Use UUIDs for public IDs
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  public_id UUID DEFAULT gen_random_uuid() UNIQUE,
  email VARCHAR(255) UNIQUE NOT NULL,
  created_at TIMESTAMPTZ DEFAULT NOW(),
  updated_at TIMESTAMPTZ DEFAULT NOW()
);

-- Soft deletes
ALTER TABLE users ADD COLUMN deleted_at TIMESTAMPTZ;

-- Indexes
CREATE INDEX idx_users_email ON users(email);
CREATE INDEX idx_users_created ON users(created_at DESC);
```

### Query Patterns
```sql
-- Pagination with cursor
SELECT * FROM posts
WHERE created_at < $cursor
ORDER BY created_at DESC
LIMIT 20;

-- Efficient counting
SELECT reltuples::bigint AS estimate
FROM pg_class WHERE relname = 'users';
```

## Authentication

### JWT Pattern
```typescript
interface TokenPayload {
  sub: string;      // User ID
  iat: number;      // Issued at
  exp: number;      // Expiration
  scope: string[];  // Permissions
}

function verifyToken(token: string): TokenPayload {
  return jwt.verify(token, SECRET) as TokenPayload;
}
```

### Middleware
```typescript
async function authenticate(req: Request, res: Response, next: Next) {
  const token = req.headers.authorization?.replace('Bearer ', '');
  if (!token) {
    return res.status(401).json({ error: 'Unauthorized' });
  }

  try {
    req.user = verifyToken(token);
    next();
  } catch {
    res.status(401).json({ error: 'Invalid token' });
  }
}
```

## Caching Strategy

```typescript
// Cache-aside pattern
async function getUser(id: string): Promise<User> {
  const cached = await redis.get(`user:${id}`);
  if (cached) return JSON.parse(cached);

  const user = await db.users.findById(id);
  await redis.setex(`user:${id}`, 3600, JSON.stringify(user));
  return user;
}

// Cache invalidation
async function updateUser(id: string, data: Partial<User>) {
  await db.users.update(id, data);
  await redis.del(`user:${id}`);
}
```

## Rate Limiting

```typescript
const limiter = rateLimit({
  windowMs: 60 * 1000,  // 1 minute
  max: 100,             // 100 requests per window
  keyGenerator: (req) => req.ip,
  handler: (req, res) => {
    res.status(429).json({ error: 'Too many requests' });
  }
});
```

## Observability

- **Logging**: Structured JSON logs with request IDs
- **Metrics**: Request latency, error rates, queue depths
- **Tracing**: Distributed tracing with correlation IDs
- **Health checks**: `/health` and `/ready` endpoints

Files: 1

Size: 3.3 KB

Complexity: 12/100

Category: Design

Source: https://github.com/skillcreatorai/ai-agent-skills/tree/main/skills/backend-development

Related in Design

contribute

Included

Local-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".

Designscripts

architectural-analysis

Included

User-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).

Designscripts

mcp

Included

Model Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.

Designscripts

react-native-skia

Included

Design, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.

Designscripts

plaid

Included

Product Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".

Designscripts

nextjs-framer-motion-animations

Included

Adds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.

Designscripts