# vtex-io-service-apps

Guides backend service development under node/ in VTEX IO apps. Configures routes, middleware chains, and @vtex/api clients for background tasks or APIs.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1200 installs · ★ 46
- Author: vtex
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/vtex/skills/tree/HEAD/skills/vtex-io-service-apps/SKILL.md
- Updated: 2026-10-14
- HTML: https://affpapa.org/en/nevibecode/skills/vtex-io-service-apps

## What it does

This skill configures the backend entry point in `node/index.ts` with the `Service` class. It connects HTTP routes from `service.json`, event handlers, and GraphQL resolvers to the `ctx` execution context.

Network requests rely on specialized classes. Use `JanusClient` for internal VTEX gateways and `ExternalClient` for third-party endpoints. Queries to Master Data v2 go through `MasterDataClient`. Custom connectors register inside an `IOClients` class, where `getOrSet` instantiates them on first access.

Direct calls via `fetch` or `axios` fail because the platform firewall drops raw outbound connections. All traffic must pass through `@vtex/api` clients. Instantiating client classes with `new` is also prohibited; handlers must access them via `ctx.clients` to keep authentication tokens and metric tracking intact.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add vtex/skills --skill vtex-io-service-apps -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/vtex-io-service-apps/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/vtex-io-service-apps/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add vtex/skills --skill vtex-io-service-apps -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/vtex-io-service-apps/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add vtex/skills --skill vtex-io-service-apps -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/vtex-io-service-apps/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install vtex/skills vtex-io-service-apps
```

2. **Manually: put the files in place**
- File: `.github/skills/vtex-io-service-apps/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add vtex/skills --skill vtex-io-service-apps -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/vtex/skills --path skills/vtex-io-service-apps
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/vtex-io-service-apps/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add vtex/skills --skill vtex-io-service-apps -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/vtex/skills/tree/HEAD/skills/vtex-io-service-apps/SKILL.md

## When to use it
- Define backend routes and middleware chains in `service.json`
- Integrate third-party REST services with `ExternalClient`
- Register custom API connectors inside `IOClients` using lazy loading
- Replace forbidden `fetch` or `axios` calls with `@vtex/api` wrappers

## Example prompts
- Write a middleware handler that fetches catalog items through `ctx.clients.catalog`
- Create an `ExternalClient` subclass to query an external shipping API with custom headers
- Set up the `node/index.ts` file with typed `Service` configuration and client declarations

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From the same set: [vtex/skills](https://affpapa.org/en/nevibecode/by/vtex/skills.md) — 38 cards

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