Proxy Fetch Server

by Nicholas C. Zakas

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Description

A Node.js server that uses a proxy agent to make fetch requests. Built with Hono, this server accepts POST requests with URLs to fetch through a configurable proxy.

The intended use is as a serverless function.

Installation

npm install @humanwhocodes/proxy-fetch-server

Usage

Starting the Server

You can start the server using npx:

npx @humanwhocodes/proxy-fetch-server

Configuration

The server is configured using environment variables:

• FETCH_PROXY (conditionally required) - A universal proxy URI that will be used for both HTTP and HTTPS requests. When set, this supersedes both http_proxy and https_proxy, allowing you to configure the proxy just for the fetch request rather than the whole process.
• http_proxy (conditionally required) - The proxy server to use for requests that use the http protocol
• https_proxy (conditionally required) - The proxy server to use for requests that use the https protocol
• no_proxy (optional) - A comma-delimited list of hostnames or hostname:port entries that should bypass using the configured proxy completely. If a hostname begins with a dot (.) then it applies to all subdomains. For instance .humanwhocodes.com applies to humanwhocodes.com, www.humanwhocodes.com, newsletter.humanwhocodes.com, etc.
• PROXY_FETCH_KEY (optional) - The expected Bearer token in the Authorization header
• PORT (optional) - The port to start the server on (default: 8080)
• PROXY_TOKEN (optional) - The token that the proxy expects
• PROXY_TOKEN_TYPE (optional) - The token type prefix for the proxy (default: "Bearer")

Either FETCH_PROXY or at least one of http_proxy and https_proxy is required.

Example:

http_proxy=http://proxy.example.com:8080 \
https_proxy=http://proxy.example.com:8080 \
no_proxy=localhost,.internal.com \
PROXY_FETCH_KEY=my-secret-key \
PORT=3000 \
PROXY_TOKEN=proxy-secret \
PROXY_TOKEN_TYPE=Bearer \
npx @humanwhocodes/proxy-fetch-server

Or, using FETCH_PROXY to set both HTTP and HTTPS proxy to the same value:

FETCH_PROXY=http://proxy.example.com:8080 \
no_proxy=localhost,.internal.com \
PROXY_FETCH_KEY=my-secret-key \
PORT=3000 \
PROXY_TOKEN=proxy-secret \
PROXY_TOKEN_TYPE=Bearer \
npx @humanwhocodes/proxy-fetch-server

Making Requests

Send a POST request to the root endpoint (/) with:

• Authorization header (optional): Bearer <PROXY_FETCH_KEY> - Required only if PROXY_FETCH_KEY is configured
• Request body: JSON object with a url property

Example using curl:

curl -X POST http://localhost:8080/ \
  -H "Authorization: Bearer my-secret-key" \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com"}'

The server will:

1. Validate the Bearer token (if configured)
2. Fetch the specified URL through the configured proxy
3. Return the response with the same status code and content type

Programmatic Usage

You can also use this package programmatically:

import { createApp } from "@humanwhocodes/proxy-fetch-server";

const app = createApp({
	key: "my-secret-key",
	httpProxy: "http://proxy.example.com:8080",
	httpsProxy: "http://proxy.example.com:8080",
	noProxy: ["localhost", ".internal.com"],
	proxyToken: "proxy-secret",
	proxyTokenType: "Bearer",
});

// Use with your preferred Node.js server adapter

Configuration options:

• key (string, optional) - The expected Bearer token in the Authorization header
• httpProxy (string, conditionally required) - The proxy server to use for HTTP requests
• httpsProxy (string, conditionally required) - The proxy server to use for HTTPS requests
• noProxy (string[], optional) - Array of hostnames or hostname:port entries to bypass proxy
• proxyToken (string, optional) - The token that the proxy expects
• proxyTokenType (string, optional) - The token type prefix for the proxy (default: "Bearer")

Either httpProxy or httpsProxy is required.

License

Copyright 2025 Nicholas C. Zakas

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.