# Secure internal communication between services (beta) By Steven Van · 2026-07-01 In beta, services declare bindings to call each other via injected internal URLs, with routing and TLS handled by Vercel. [Vercel]() now offers service bindings in beta, letting one service in a multi-service deployment call another over its internal network instead of the public internet. A binding is declared on the caller service in vercel.json, naming the target service and an environment variable. Vercel injects that variable with a generated internal URL, so a Next.js frontend can reach a FastAPI backend with a normal fetch() call, while Vercel handles the routing, authentication, and TLS. The target service stays unreachable from outside unless it also has its own public rewrite. - Internal calls skip the public request pipeline: Firewall, Deployment Protection, top-level middleware, and CDN request accounting don't apply. - A binding grants reachability only. It does not authenticate or authorize the call, so that has to be handled in application code. - Bindings resolve only in a service's functions at runtime, not during builds or in middleware. - They aren't yet available for services on the Go or Rust runtime, unless built as a container image. Full detail is in the [service bindings documentation](). [![]()]() ![Vercel]() Vercel The platform for frontend developers — deploy, preview, and scale web apps and AI agents with zero config. [View Vercel →]() Sources [Original source]() [Read Secure internal communication between services (beta) on Creators Toolbox]() --- Canonical source: https://creatorstoolbox.com/blog/vercel-secure-internal-communication-between-services-beta