Peren documentation
Outbound fetch
Allowlist hosts and call them through an outbound binding.
An outbound binding lets a Worker call specific hosts through env.NAME.fetch. Peren refuses any other host for that binding. The binding carries no credentials.
Prerequisites
- A fleet file with
[node],[bucket],[mtls], one service, and one socket - A Worker bundle that exports
fetch - The upstream host name you will allowlist
Configure the binding
Write fleet.toml:
[node]
node_id = "00000000-0000-0000-0000-000000000001"
advertise_addr = "127.0.0.1:7000"
listen = "127.0.0.1:7000"
[bucket]
kind = "memory"
[mtls]
ca_cert_path = "./certs/ca.pem"
leaf_cert_path = "./certs/leaf-cert.pem"
leaf_key_path = "./certs/leaf-key.pem"
[[services]]
name = "api"
worker_bundle_path = "worker.js"
compatibility_date = "2026-01-01"
[services.bindings.PUBLIC_API]
type = "outbound"
allowed_hosts = ["api.example.com"]
[[sockets]]
name = "public"
listen = "127.0.0.1:8080"
service = "api"type must be outbound. allowed_hosts lists host names the binding may call.
Call the binding
Write worker.js:
export default {
async fetch(request, env) {
return env.PUBLIC_API.fetch("https://api.example.com/status");
},
};The Worker calls env.PUBLIC_API.fetch. Global fetch uses the union of outbound allowlists on that service. Redirect targets are not checked again.
Success
The upstream HTTP status and body are returned to the Worker as the Response from env.PUBLIC_API.fetch.
Failure
A host that is not in allowed_hosts throws TypeError before the request leaves the node.