bff-architecture

bff-architecture is a cursor rule for Cursor from GoranErhartic/cursor-development-rules. It costs 20 tokens per session (3,756 once invoked), scanned A, original, MIT.

An architecture guide for a backend-for-frontend service: a layer that adapts backend services to the needs of a specific client application.

In plain words
What is it for?
Use it when designing controllers, client-specific endpoints, service aggregation, Clean Architecture layers, CQRS, or vertical slices.
Why use it?
It keeps frontend-facing code separate from backend complexity and defines how data, authentication, and application logic are organized.

Cursor rule for Cursor

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 rules/goranerhartic/cursor-development-rules/bff-architecture
Clone the repo
git clone --depth 1 https://github.com/GoranErhartic/cursor-development-rules

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for bff-architecture

README.md
[![agentmods](https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/bff-architecture.svg)](https://agentmods.dev/rules/goranerhartic/cursor-development-rules/bff-architecture)
Your own site
<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/bff-architecture"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/bff-architecture.svg" alt="Measured on agentmods" height="20"></a>
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,756 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 $0.00020 $0.03756
Opus 5 $0.00010 $0.01878
Sonnet 5 $0.00004 $0.00751
Haiku 4.5 $0.00002 $0.00376

Measured 4d ago against content hash eea78fe76daa, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bff-architecture 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 4d ago.

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.

.cursor/rules/languages/java/bff-architecture.mdc · 260 lines

How it starts

The opening of the file, as written. The whole thing — 260 lines — stays where its author put it; the contents beside it link to each section on GitHub.

BFF Architecture Patterns

What is a BFF?

A Backend-For-Frontend (BFF) is a service layer that sits between a client application and backend microservices. It:

  • Aggregates data from multiple backend APIs
  • Transforms backend responses to client-specific formats
  • Handles authentication token pass-through or exchange
  • Provides client-optimized endpoints
  • Shields frontend from backend complexity

Architecture Overview

This BFF follows Clean Architecture combined with CQRS and Vertical Slice Architecture.

┌─────────────────────────────────────────────────────────────────────┐
│                              WEB                                     │
│  Controllers, Request/Response DTOs, Exception Handlers             │
│  (Composition root - may access all inner layers)                   │
├─────────────────────────────────────────────────────────────────────┤
│                         INFRASTRUCTURE                               │
│  HTTP Clients, Adapters, Filters, Interceptors, Config              │
│  (Implements Application ports)                                      │
├─────────────────────────────────────────────────────────────────────┤
│                          APPLICATION                                 │
│  CQRS Handlers, Ports (interfaces), Feature DTOs                    │
│  (Depends only on Domain)                                           │
├─────────────────────────────────────────────────────────────────────┤
│                            DOMAIN                                    │
│  Core entities, Value objects, Errors, Enums                        │
│  (No external dependencies - framework agnostic)                    │
└─────────────────────────────────────────────────────────────────────┘

Read the full file on GitHub · 260 lines

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. 4d ago First seen · 260 lines · 20 tokens per session scan A eea78fe76daa

Subscribe to this mod's changes

bff-architecture is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 6mo ago), licensed MIT. It adds 20 tokens to every session and 3,756 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 2026-08-30.