Setting Up SMTP IMAP Proxy Service

Notice

If you are using resend, you can directly use resend's SMTP service without needing this service

Why Do You Need SMTP IMAP Proxy Service

SMTP and IMAP have a wider range of application scenarios

How to Set Up SMTP IMAP Proxy Service

Local Run

cd smtp_proxy_server/
# Copy configuration file and modify it
# Your worker address, proxy_url=https://temp-email-api.xxx.xxx
# Your SMTP service port, port=8025
cp .env.example .env
python3 -m venv venv
./venv/bin/python3 -m pip install -r requirements.txt
./venv/bin/python3 main.py

Docker Run

cd smtp_proxy_server/
docker-compose up -d

Modify the environment variables in docker-compose.yaml, note to choose the appropriate tag

proxy_url is the URL address of the worker

services:
  smtp_proxy_server:
    image: ghcr.io/dreamhunter2333/cloudflare_temp_email/smtp_proxy_server:latest
    # build:
    #   context: .
    #   dockerfile: dockerfile
    container_name: "smtp_proxy_server"
    ports:
      - "8025:8025"
      - "11143:11143"
    environment:
      - proxy_url=https://temp-email-api.xxx.xxx
      - port=8025
      - imap_port=11143

Environment Variables

Variable	Default	Description
proxy_url	http://localhost:8787	Worker backend URL
port	8025	SMTP port
imap_port	11143	IMAP port
smtp_tls_cert	empty	SMTP TLS certificate file path (PEM), enables STARTTLS when configured
smtp_tls_key	empty	SMTP TLS private key file path (PEM)
imap_tls_cert	empty	IMAP TLS certificate file path (PEM), enables STARTTLS when configured
imap_tls_key	empty	IMAP TLS private key file path (PEM)
imap_cache_size	500	Max cached messages per mailbox
imap_http_timeout	30.0	Backend HTTP request timeout (seconds)
imap_flag_db_path	data/imap_flags.db	SQLite file storing IMAP flags (e.g. \Seen) so STORE (mark as read) survives client reconnects. Mount a volume over its parent directory so it persists across container restarts

Enabling STARTTLS

Configure the TLS certificate environment variables for SMTP and/or IMAP to enable STARTTLS support. SMTP and IMAP can share the same certificate.

# .env example
smtp_tls_cert=/path/to/cert.pem
smtp_tls_key=/path/to/key.pem
imap_tls_cert=/path/to/cert.pem
imap_tls_key=/path/to/key.pem

In Docker Compose:

environment:
  - smtp_tls_cert=/certs/cert.pem
  - smtp_tls_key=/certs/key.pem
  - imap_tls_cert=/certs/cert.pem
  - imap_tls_key=/certs/key.pem
volumes:
  - ./certs:/certs:ro

IMAP Login Methods

Two login methods are supported:

Method	Username	Password	Description
JWT Credential	Email address	JWT token	Address credential from frontend, direct authentication
Address+Password	Email address	Address password	Verified via backend /api/address_login

The system automatically detects the password format: a three-segment string starting with eyJ is treated as a JWT; otherwise it is treated as a password and verified via the backend.

Using Thunderbird to Login

Download Thunderbird

For password, enter the email address credential or email address password