Inngest Function Builder

Inngest is an event-driven background job platform that runs on your existing infrastructure. You define functions that trigger on events (like 'user.signup') or cron schedules. Inngest handles retries, concurrency, throttling, and step-level durability without requiring a separate queue infrastructure. Functions run as HTTP endpoints — Inngest calls your server when a trigger fires.

step.run wraps a code block in a durable, retried step — if the function crashes mid-execution, Inngest replays it from the last successful step rather than re-running everything. step.sleep pauses execution for a duration without holding a server connection — ideal for delays between retries or reminder sequences. step.waitForEvent pauses execution until a specific event is received or a timeout expires — perfect for human-in-the-loop flows like email confirmation.

Concurrency limiting controls how many simultaneous runs of a function can execute. Use it to prevent overwhelming downstream services (e.g., limit 10 concurrent Stripe API calls), to enforce per-user rate limits (using concurrency key by user ID), or to protect database connection pools. Inngest queues excess runs and drains them as capacity frees up.

cancelOn lets you automatically cancel a running function when a specific event is received. For example: start an order fulfillment function on 'app/order.created', but cancel it immediately if 'app/order.cancelled' arrives. This prevents wasted work and ensures clean state transitions without requiring manual cancellation logic in your code.

Concurrency limits how many runs execute simultaneously at any moment. Throttle limits how many runs can START within a time period — for example, no more than 100 per minute — regardless of how long each run takes. Use throttle for rate-limiting external API calls (respecting third-party rate limits) and concurrency for controlling resource utilization.

No. All code generation runs entirely in your browser using JavaScript. Your function names, event names, and step configurations never leave your machine.