Fetch TypeScript only

A Fetch API-compatible function is exported to allow you to make any HTTP requests durable if they're called within an Inngest function.

import { fetch } from "inngest";

const api = new MyProductApi({ fetch });

The request itself is also made by Inngest's servers, meaning your service does not have to be active and waiting for the response.

Within steps

By default, using Inngest's fetch should retain all functionality of requests outside of an endpoint, but ensure those from inside are durable.

import { fetch } from "inngest";

const api = new MyProductApi({ fetch });

// A call outside will fall back to the global fetch
await api.getProduct(1);

// A call from inside an Inngest function will be made durable
inngest.createFunction(
  { id: "my-fn" },
  { event: "product/activated" },
  async () => {
    await api.getProduct(1);
  },
);

The same fetch is, however, also exported as step.fetch, allowing you to create your APIs isolated within the function instead:

inngest.createFunction(
  { id: "my-fn" },
  { event: "product/activated" },
  async ({ step }) => {
    const api = new MyProductApi({ fetch: step.fetch });

    await api.getProduct(1);
  },
);

Fallbacks

By default, it will gracefully fall back to the global fetch if called outside of an Inngest function, though a custom fallback can also be set using the config method:

import { fetch } from "inngest";

const api = new MyProductApi({
  fetch: fetch.config({ fallback: myCustomFetch }),
});

You can also disable the fallback entirely:

import { fetch } from "inngest";

const api = new MyProductApi({
  fetch: fetch.config({ fallback: undefined }),
});

How it works

Inngest's fetch function uses some of the basic building blocks of Inngest to allow seamless creation of optionally-durable code. When it's called, it will:

• Check the context we're running in
• If we're not in an Inngest function, optionally use the fallback, else
• Report the request we want to make to Inngest
• Inngest makes the request
• Inngest continues the function with the Response we received from making your request

Critically, this means that your service does not have to be active for the duration of the call; we'll continue your function when we have a result, as well as keeping it durable!