Async Api Routes

---
description: Imported skill async_api_routes from vercel
name: async_api_routes
signature: 523338540d73427dc14c0cbb19f2741ebccdf8b105a7b2c1b33d2905cf237a42
source: /a0/tmp/skills_research/vercel/skills/react-best-practices/rules/async-api-routes.md
---

---
title: Prevent Waterfall Chains in API Routes
impact: CRITICAL
impactDescription: 2-10× improvement
tags: api-routes, server-actions, waterfalls, parallelization
---

## Prevent Waterfall Chains in API Routes

In API routes and Server Actions, start independent operations immediately, even if you don't await them yet.

**Incorrect (config waits for auth, data waits for both):**

```typescript
export async function GET(request: Request) {
  const session = await auth()
  const config = await fetchConfig()
  const data = await fetchData(session.user.id)
  return Response.json({ data, config })
}
```

**Correct (auth and config start immediately):**

```typescript
export async function GET(request: Request) {
  const sessionPromise = auth()
  const configPromise = fetchConfig()
  const session = await sessionPromise
  const [config, data] = await Promise.all([
    configPromise,
    fetchData(session.user.id)
  ])
  return Response.json({ data, config })
}
```

For operations with more complex dependency chains, use `better-all` to automatically maximize parallelism (see Dependency-Based Parallelization).