Fax Machine

Do you ever need to send a fax? No? Neither do I. But if you do, it sure is a hassle. Who has a fax machine these days? Well, here is a virtual fax machine, built with Telnyx and Cloudflare Workers.

Routes

Here are the important paths that the Worker serves:

• Send a fax at /.
• Trigger a database cleanup at /cron.
• Telnyx will send status updates to /webhook

Setup

Telnyx

• Save your API key and public key for later.
• Create a Fax API Application.
  • Set the webhook URL to your Cloudflare Worker's URL (https://fax-machine.[your-subdomain].workers.dev/webhook).
  • Enter your email address to receive faxes.
  • Save the app, and then copy its App ID for later.
• Assign the fax application to your Telnyx phone number.

Cloudflare

• Create a bucket in R2 called fax-machine.
• Create a database in D1 called fax-machine.
  • Copy its database ID for later.
  • Run npx wrangler d1 execute fax-machine --file=./database.sql to create the Faxes table.
    • Note: this command will delete the Faxes table if it already exists.
• Set the environment variables and enter your database ID in wrangler.toml.
  • Alternatively configure them as secrets with npx wrangler secret put <key>.
• Publish the Worker with npx wrangler publish.

Bonus: Access Control

By default, this Worker lets anyone send faxes. We can use Cloudflare Access to restrict who can send faxes:

• Configure a custom domain for your Worker.
  • Disable the fax-machine.[your-subdomain].workers.dev route, so the Fax Machine is only accessible through the custom domain.
• Create an Access application for your custom domain with your desired access controls.
• Create another Access application for the /media path with a Bypass policy to allow anyone to fetch media.
  • This allows Telnyx to retrieve the fax PDFs.