can now automatically inject HTTP headers into outbound requests from sandboxed code. This keeps API keys and tokens safely outside the sandbox VM boundary, so apps running inside the sandbox can call authenticated services without ever accessing the credentials. Header injection is configured as part of the network policy using . When the sandbox makes an HTTPS request to a matching domain, the firewall adds or replaces the specified headers before forwarding the request.Vercel Sandboxtransform This is designed for AI agent workflows where prompt injection is a real threat. Even if an agent is compromised, there's nothing to exfiltrate, as the credentials only exist in a layer outside the VM.

Injection rules work with all egress network policy configurations, including open internet access. To allow general traffic while injecting credentials for specific services: Like all network policy settings, injection rules can be updated on a running sandbox without restarting it. This enables multi-phase workflows, inject credentials during setup, then remove them before running untrusted code: Available to all Pro and Enterprise customers. Learn more in the .documentation Read more…