# Vercel Daemons can now call services through bindings

published: 2026-10-30T21:05:42.621Z
topic: infrastructure
source: https://vercel.com/changelog/vercel-daemons-can-now-call-services-with-bindings
url: https://aiagentnews.io/stories/vercel-daemons-can-now-call-services-through-bindings

Vercel Daemons can now call other services in their deployment through service bindings, and the called services stay private. A binding is declared in vercel.toml and places the target service's URL in an environment variable the daemon can read.

A daemon declares a binding in its vercel.toml file, naming the target service and the environment variable that will hold that service's URL. In Vercel's example, a worker daemon binds to an api service and receives its URL as API_URL. The daemon then calls that URL with a standard fetch request, like any other HTTP endpoint.

Vercel handles internal routing, authentication and TLS, so the bound service does not need a public address. Bindings only run one way, and services cannot bind to daemons. Each instance keeps calling the deployment that started it, even after a promotion or rollback.

The example config also runs the worker daemon with one instance in the iad1 region, built from a Dockerfile in its worker/ directory.

## Why it matters if you build agents

Agent backends split into a daemon and a private service can now reach each other without a public endpoint or custom authentication code. Because each instance stays pinned to the deployment that started it, developers should check how in-flight work behaves during promotions and rollbacks.