Vtex Io Service Apps

If you're building backend services in VTEX IO, this skill keeps you on the rails. It covers the Service class entry point, the ctx.clients pattern for accessing APIs, and how to extend JanusClient or ExternalClient properly. The hard constraints are worth reading: you must use @vtex/api clients instead of axios or fetch (the platform firewall blocks raw HTTP libraries), and you must access clients through ctx.clients, never instantiate them directly. The skill also warns against monolithic service apps with more than 10 routes. Good reference for the client hierarchy and when to use JanusClient versus ExternalClient versus AppClient.

skills.sh installs: 1.3K
GitHub stars: 47
last updated: Aug 21, 2026

View on GitHub

Install

$ npx -y skills add vtex/skills --skill vtex-io-service-apps --agent claude-code

Installs into .claude/skills of the current project.

Files

Backend Service Apps & API Clients

When this skill applies

Use this skill when developing a VTEX IO app that needs backend logic — REST API routes, GraphQL resolvers, event handlers, scheduled tasks, or integrations with VTEX Commerce APIs and external services.

Building the Service entry point (node/index.ts) with typed context, clients, and state
Creating and registering custom clients extending JanusClient or ExternalClient
Using ctx.clients to access clients with built-in caching, retry, and metrics
Configuring routes and middleware chains in service.json

Do not use this skill for: