RelaySMS Mail

The rmail adapter gives each user an email alias tied to their phone number, and sends email from it through SimpleLogin. Users link with a code sent over a messaging app by Shortmesh Authy. It’s the adapter that publishes offline payloads, each from a new random alias.

Last checked against SimpleLogin, Shortmesh Authy and Google: 2026-10-22.

Requirements

• A SimpleLogin Premium account, which custom domains and sending to new contacts require
• A domain whose DNS you control
• An SMTP account allowed to send as your SimpleLogin mailbox address
• A self-hosted Shortmesh Authy, to send the login codes

SimpleLogin

1. Sign up at app.simplelogin.io. The signup address becomes your mailbox; to use another, add and verify it under Mailboxes.
2. Add your domain, or a subdomain such as mail.example.com, under Custom domains.
3. Create the DNS records the domain’s page lists: ownership TXT, MX, SPF, DKIM and DMARC. SimpleLogin marks the last three optional; without them, mail sent from aliases doesn’t arrive.
4. Create an API key.

SMTP

The adapter sends each message from your mailbox address over SMTP, and SimpleLogin relays it from the user’s alias.

For a Gmail mailbox, use smtp.gmail.com, port 465, the Gmail address, and an app password, which needs 2-Step Verification on the account.

Shortmesh Authy

Run Authy-API with its Interface-API, then in the Interface-API’s admin UI:

1. Under Devices, link the phone that sends the codes.
2. Under Tokens, create a token.

Configure the adapter

This example uses a Gmail mailbox:

sudo ./publisher.sh platforms add \
  https://github.com/smswithoutborders/relaysms-mail-pnba-adapter
sudo ./publisher.sh platforms config set rmail \
  sl_primary_email=you@gmail.com sl_primary_domain=mail.example.com \
  smtp_host=smtp.gmail.com smtp_port=465 smtp_username=you@gmail.com \
  authy_base_url=https://authy.example.com authy_sender=+237600000000
sudo ./publisher.sh platforms config set rmail sl_api_key smtp_password authy_token

sudo ./publisher.sh platforms config show rmail lists the optional settings, such as alias prefixes.

Check it

sudo ./publisher.sh platforms list --name rmail

You should see ✓ under Configured.

curl https://authy.example.com/api/v1/platforms

You should see the channels Authy can send codes on, such as signal.

Troubleshooting

No mailbox for <EMAIL>

sl_primary_email isn’t a verified SimpleLogin mailbox.

No suffix available for hostname '<DOMAIN>'

sl_primary_domain isn’t a verified custom domain in SimpleLogin.

Sending fails with an SMTP authentication error

For Gmail, use an app password, not the account password. A changed account password revokes app passwords.

Recipients don’t get the email

Check the domain’s SPF, DKIM and DMARC records on its SimpleLogin page.

SimpleLogin refuses to create a contact

The account isn’t Premium.

Users don’t get a login code

Check that the sender device is linked and online, and that the channel the app sends, such as signal, appears at <AUTHY_BASE_URL>/api/v1/platforms.

Next steps

Register a gateway client to relay SMS to the Publisher.