inngest-nextjs-patterns

Inngest + Next.js Patterns

Templates and conventions for building event-driven, durable background work on Inngest from a Next.js App Router project. The skill enforces the conventions Inngest's own docs use (decentralized eventType() schemas, kebab-case stable function IDs, idempotent steps) so that retries, replays, and concurrency controls actually do what they advertise.

When to Apply

Read this skill when you are:

• Setting up Inngest in a Next.js app for the first time (client + route handler + first function)
• Adding a new background job, webhook handler, or scheduled task to a Next.js app
• Defining a new domain event that other functions will trigger on
• Orchestrating multi-step work that must survive process restarts (durable workflows, sagas)
• Reviewing existing Inngest code for event naming, step idempotency, or stable function IDs
• Migrating from setTimeout / a queue library / a cron service to Inngest's durable execution model

How to Use

1. First time in this codebase? Read references/conventions.md before writing anything. The conventions explain why event names take a specific shape, why function IDs must be stable, and why every step.run must be idempotent — once you understand the reasoning, the templates make sense.
2. Pick a template from the catalog below based on what you're creating.
3. Render it by substituting the documented parameters. Each template has a parameter table at the top of its file.
4. Wire it up: new functions must be added to src/inngest/functions/index.ts (the registry the route handler reads). The conventions doc shows the registry pattern.

Available Templates

Template	Output Path	Use When
client.ts.template	src/inngest/client.ts	One-time setup: create the singleton Inngest client. Generate once per app.
route-handler.ts.template	src/app/api/inngest/route.ts	One-time setup: the App Router endpoint Inngest hits to invoke your functions. Generate once per app.
event.ts.template	src/inngest/events/{domain}.ts	Defining a new typed event (with Zod schema) that producers send and functions consume.
function.ts.template	src/inngest/functions/{name}.ts	Standard event-triggered durable function with steps. Parameterized retries, concurrency, throttle, debounce, cancelOn, onFailure.
function-cron.ts.template	src/inngest/functions/{name}.ts	Scheduled function — runs on a cron expression (with timezone). Optionally also accepts a manual event trigger for ad-hoc invocation.
function-fan-out.ts.template	src/inngest/functions/{name}.ts	Orchestrator that receives one event and fans out work — via step.sendEvent (fire-and-forget) or Promise.all(step.invoke(...)) (wait for results).

Quick Reference

• Event name shape: domain/entity.verb_past — e.g., app/user.created, shop/order.placed, billing/invoice.paid. The conventions doc has the full rule.
• Function id: stable kebab-case, never rename it after deploy — Inngest uses it as the durable state key.
• Step id: descriptive kebab-case, also durable; changing one re-runs that step on replay.
• Idempotency: every step.run must be safely retryable. If it calls a third-party API that mutates state, pass an idempotency key.
• Dev server: npx inngest-cli@latest dev, then UI at http://localhost:8288. Set INNGEST_DEV=1 in .env.local to point the SDK at it.

Project Layout Assumption

Templates assume a src/ directory with App Router:

src/
├── app/api/inngest/route.ts          # generated by route-handler template
└── inngest/
    ├── client.ts                     # generated by client template
    ├── events/                       # one file per domain (events.shop.ts, events.user.ts)
    │   └── {domain}.ts               # generated by event template
    └── functions/
        ├── index.ts                  # registry: re-exports all functions as an array
        └── {name}.ts                 # generated by function/cron/fan-out templates

If your project uses a different layout (no src/, or Pages Router), override the output paths in config.json. The conventions doc explains the trade-offs.

Setup

config.json controls path overrides. On first use, check whether its fields are filled in — if not, ask the user before generating (project root differs from the default assumption).

Related Skills

• vercel:ai-sdk — if your Inngest functions invoke LLMs, the AI SDK gives you streaming + provider abstraction; pair them with step.run for retry safety.
• vercel:vercel-functions — Inngest's serve() adapter for Next.js runs as a Vercel Serverless Function by default; the AI SDK skill has notes on Fluid Compute and timeout extension for long agent runs.