The Fetch API is a new set of APIs introduced by Inngest, allowing developers to make durable HTTP requests within an Inngest function. This enables offloading of third-party API requests and data fetching to the Inngest Platform, saving compute and improving reliability. The `step.fetch()` API brings benefits similar to `step.run()`, but with the added advantage of offloading HTTP requests, removing potential serverless timeout issues. It is also compatible with the `Promise` API, enabling parallel processing of multiple requests. Additionally, the `fetch()` utility provides a way to make third-party library HTTP requests durable, while all `step.fetch()` and `fetch()` calls appear in Inngest Traces for improved observability.