Implementing Secure Communication Between Services

With Vercel's Service Bindings, services within the same deployment environment can securely call one another. When a specific service declares a binding to another service, Vercel automatically injects the configured environment variables.

Developers can simply use a standard fetch() request, and internal rewrites, routing, authentication, and TLS handling are all performed automatically. This allows you to build multi-service applications—such as a Next.js frontend calling a FastAPI backend—while maintaining service isolation and simple routing configuration.

This communication occurs only through Vercel's internal network, and traffic never leaves to the external public network. All requests are forwarded to the target service through Vercel's internal routing layer, and HTTPS communication is possible without any separate certificate setup.

Service-to-service calls are billed as Service Requests and Fast Origin Transfer, and are not included in CDN requests or Fast Data Transfer.