backend-patterns

A set of guidance for common backend programming patterns, covering APIs, data access, caching, authentication, authorization, and error handling. Backend code runs on servers and handles data and application rules.

In plain words
What is it for?
Use it when designing APIs or services, working with databases, adding repository or service layers, implementing authentication, or handling errors.
Why use it?
It helps keep server-side code consistent and separates concerns such as business logic, database access, and access control.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/drag88/claude-dev-framework/backend-patterns
Any agent
npx skills add drag88/claude-dev-framework --skill backend-patterns
Clone the repo
git clone --depth 1 https://github.com/drag88/claude-dev-framework

Made for: Claude Code, Codex.

Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 827 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00025 $0.00827
Opus 5 $0.00013 $0.00413
Sonnet 5 $0.00005 $0.00165
Haiku 4.5 $0.00003 $0.00083

Measured yesterday against content hash d9238c5ad364, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backend-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/backend-patterns/SKILL.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backend Patterns Skill

Provide guidance on backend architecture patterns, API design, and server-side best practices.

When to Activate

  • During backend implementation tasks
  • When designing APIs or services
  • When working with databases and data layers
  • When implementing authentication, authorization, or security features

Pattern Index

API Design

Pattern When to Use
RESTful conventions Standard CRUD operations on resources
Response format Consistent success/error JSON structure
Pagination List endpoints returning multiple items

See references/api-design.md for REST conventions table, response formats, and pagination implementation.

Service Architecture

Pattern When to Use
Repository Separate data access from business logic
Service Layer Encapsulate business logic, coordinate side effects

See references/service-patterns.md for repository interface and service layer implementations.

Authentication & Authorization

Pattern When to Use
Auth middleware Protecting routes with Bearer token verification
Authorization middleware Role-based route protection
JWT tokens Access + refresh token generation and rotation
RBAC Permission checks with wildcard and ownership support

See references/auth-middleware.md for middleware, JWT, and RBAC implementations.

Database

Pattern When to Use
N+1 prevention Loading related data (eager load or batch)
Transactions Multi-step operations requiring atomicity
Caching (decorator) Frequently read, rarely written data

See references/database-patterns.md for N+1 fixes, transaction pattern, and cache-aside implementation.

Error Handling

Pattern When to Use
Error class hierarchy Typed errors with status codes (NotFound, Validation, etc.)
Error middleware Global Express error handler
Retry with backoff Transient failures (network, rate limits)

Read the full file on GitHub · 109 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 109 lines · 25 tokens per session scan A d9238c5ad364

Subscribe to this mod's changes

backend-patterns is a skill published in the GitHub repository drag88/claude-dev-framework (2 stars, last pushed 1mo ago), licensed MIT. It adds 25 tokens to every session and 827 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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