The SimpleLogin back-end

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SimpleLogin | Protect your online identity with email alias

Your email address is your online identity. When you use the same email address everywhere, you can be easily tracked. More information on

This README contains instructions on how to self host SimpleLogin.

Once you have your own SimpleLogin instance running, you can change the API URL in SimpleLogin's Chrome/Firefox extension, Android/iOS app to your server.

SimpleLogin roadmap is at and our forum at, feel free to submit new ideas or vote on features.


  • a Linux server (either a VM or dedicated server). This doc shows the setup for Ubuntu 18.04 LTS but the steps could be adapted for other popular Linux distributions. As most of components run as Docker container and Docker can be a bit heavy, having at least 2 GB of RAM is recommended. The server needs to have the port 25 (email), 80, 443 (for the webapp), 22 (so you can ssh into it) open.

  • a domain that you can config the DNS. It could be a sub-domain. In the rest of the doc, let's say it's for the email and for SimpleLogin webapp. Please make sure to replace these values by your domain name whenever they appear in the doc. A trick we use is to download this README file on your computer and replace all occurrences by your domain.

Except for the DNS setup that is usually done on your domain registrar interface, all the below steps are to be done on your server. The commands are to run with bash (or any bash-compatible shell like zsh) being the shell. If you use other shells like fish, please make sure to adapt the commands.

Some utility packages

These packages are used to verify the setup. Install them by:

sudo apt update && sudo apt install -y dnsutils

Create a directory to store SimpleLogin data:

mkdir sl
mkdir sl/pgp # to store PGP key
mkdir sl/db # to store database
mkdir sl/upload # to store quarantine emails

From Wikipedia

DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect forged sender addresses in emails (email spoofing), a technique often used in phishing and email spam.

Setting up DKIM is highly recommended to reduce the chance your emails ending up in the recipient's Spam folder.

First you need to generate a private and public key for DKIM:

openssl genrsa -out dkim.key 1024
openssl rsa -in dkim.key -pubout -out

You will need the files dkim.key and for the next steps.

For email gurus, we have chosen 1024 key length instead of 2048 for DNS simplicity as some registrars don't play well with long TXT record.


Please note that DNS changes could take up to 24 hours to propagate. In practice, it's a lot faster though (~1 minute or so in our test). In DNS setup, we usually use domain with a trailing dot (.) at the end to to force using absolute domain.

MX record

Create a MX record that points to with priority 10.

To verify if the DNS works, the following command

dig @ mx

should return:   3600    IN  MX  10
A record

An A record that points to your server IP. If you are using CloudFlare, we recommend to disable the "Proxy" option. To verify, the following command

dig @ a

should return your server IP.


Set up DKIM by adding a TXT record for with the following value:

v=DKIM1; k=rsa; p=PUBLIC_KEY

with PUBLIC_KEY being your but

  • remove the -----BEGIN PUBLIC KEY----- and -----END PUBLIC KEY-----
  • join all the lines on a single line.

For example, if your is

-----END PUBLIC KEY-----

then the PUBLIC_KEY would be abcdefgh.

You can get the PUBLIC_KEY by running this command:

sed "s/-----BEGIN PUBLIC KEY-----/v=DKIM1; k=rsa; p=/g" $(pwd)/ | sed 's/-----END PUBLIC KEY-----//g' |tr -d '\n' | awk 1

To verify, the following command

dig @ txt

should return the above value.


From Wikipedia

Sender Policy Framework (SPF) is an email authentication method designed to detect forging sender addresses during the delivery of the email

Similar to DKIM, setting up SPF is highly recommended. Add a TXT record for with the value:

v=spf1 mx ~all

What it means is only your server can send email with domain. To verify, the following command

dig @ txt

should return the above value.


From Wikipedia

It (DMARC) is designed to give email domain owners the ability to protect their domain from unauthorized use, commonly known as email spoofing

Setting up DMARC is also recommended. Add a TXT record for with the following value

v=DMARC1; p=quarantine; adkim=r; aspf=r

This is a relaxed DMARC policy. You can also use a more strict policy with v=DMARC1; p=reject; adkim=s; aspf=s value.

To verify, the following command

dig @ txt

should return the set value.

For more information on DMARC, please consult


Now the boring DNS stuffs are done, let's do something more fun!

If you don't already have Docker installed on your server, please follow the steps on Docker CE for Ubuntu to install Docker.

You can also install Docker using the docker-install script which is

curl -fsSL | sh
Prepare the Docker network

This Docker network will be used by the other Docker containers run in the next steps. Later, we will setup Postfix to authorize this network.

sudo docker network create -d bridge \
    --subnet= \
    --gateway= \

This section creates a Postgres database using Docker.

If you already have a Postgres database in use, you can skip this section and just copy the database configuration (i.e. host, port, username, password, database name) to use in the next sections.

Run a Postgres Docker container as your Postgres database server. Make sure to replace myuser and mypassword with something more secret.

docker run -d \
    --name sl-db \
    -e POSTGRES_PASSWORD=mypassword \
    -e POSTGRES_USER=myuser \
    -e POSTGRES_DB=simplelogin \
    -p \
    -v $(pwd)/sl/db:/var/lib/postgresql/data \
    --restart always \
    --network="sl-network" \

To test whether the database operates correctly or not, run the following command:

docker exec -it sl-db psql -U myuser simplelogin

you should be logged in the postgres console. Type exit to exit postgres console.


Install postfix and postfix-pgsql. The latter is used to connect Postfix and the Postgres database in the next steps.

sudo apt-get install -y postfix postfix-pgsql -y

Choose "Internet Site" in Postfix installation window then keep using the proposed value as System mail name in the next window.

Replace /etc/postfix/ with the following content. Make sure to replace by your domain.

# POSTFIX config file, adapted for SimpleLogin
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

appending .domain is the MUA's job.

append_dot_mydomain = no

Uncomment the next line to generate "delayed mail" warnings

delay_warning_time = 4h

readme_directory = no

See -- default to 2 on

fresh installs.

compatibility_level = 2

TLS parameters

smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtp_tls_security_level = may smtpd_tls_security_level = may

See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for

information on enabling SSL in the smtp client.

alias_maps = hash:/etc/aliases mynetworks = [::ffff:]/104 [::1]/128

Set your domain here

mydestination = myhostname = mydomain = myorigin =

relay_domains = pgsql:/etc/postfix/ transport_maps = pgsql:/etc/postfix/

HELO restrictions

smtpd_delay_reject = yes smtpd_helo_required = yes smtpd_helo_restrictions = permit_mynetworks, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, permit

Sender restrictions:

smtpd_sender_restrictions = permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain, permit

Recipient restrictions:

smtpd_recipient_restrictions = reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, permit_mynetworks, reject_unauth_destination, reject_rbl_client, reject_rbl_client, permit

Check that the ssl certificates /etc/ssl/certs/ssl-cert-snakeoil.pem and /etc/ssl/private/ssl-cert-snakeoil.key exist. Depending on the linux distribution you are using they may or may not be present. If they are not, you will need to generate them with this command:

openssl req -x509 -nodes -days 3650 -newkey rsa:2048 -keyout /etc/ssl/private/ssl-cert-snakeoil.key -out /etc/ssl/certs/ssl-cert-snakeoil.pem

Create the /etc/postfix/ file with the following content. Make sure that the database config is correctly set, replace with your domain, update 'myuser' and 'mypassword' with your postgres credentials.

# postgres config
hosts = localhost
user = myuser
password = mypassword
dbname = simplelogin

query = SELECT domain FROM custom_domain WHERE domain='%s' AND verified=true UNION SELECT '%s' WHERE '%s' = '' LIMIT 1;

Create the /etc/postfix/ file with the following content. Again, make sure that the database config is correctly set, replace with your domain, update 'myuser' and 'mypassword' with your postgres credentials.

# postgres config
hosts = localhost
user = myuser
password = mypassword
dbname = simplelogin

forward to smtp: for custom domain AND email domain

query = SELECT 'smtp:' FROM custom_domain WHERE domain = '%s' AND verified=true UNION SELECT 'smtp:' WHERE '%s' = '' LIMIT 1;

Finally, restart Postfix

sudo systemctl restart postfix
Run SimpleLogin Docker containers

To run SimpleLogin, you need a config file at $(pwd)/simplelogin.env. Below is an example that you can use right away, make sure to

  • replace by your domain,
  • set FLASK_SECRET to a secret string,
  • update 'myuser' and 'mypassword' with your database credentials used in previous step.

All possible parameters can be found in config example. Some are optional and are commented out by default. Some have "dummy" values, fill them up if you want to enable these features (Paddle, AWS, etc).

# WebApp URL

domain used to create alias

transactional email is sent from this email address

custom domain needs to point to these MX servers


By default, new aliases must end with ".{random_word}". This is to avoid a person taking all "nice" aliases.

this option doesn't make sense in self-hosted. Set this variable to disable this option.


the DKIM private key used to compute DKIM-Signature


DB Connection






Before running the webapp, you need to prepare the database by running the migration:

docker run --rm \
    --name sl-migration \
    -v $(pwd)/sl:/sl \
    -v $(pwd)/sl/upload:/code/static/upload \
    -v $(pwd)/dkim.key:/dkim.key \
    -v $(pwd)/ \
    -v $(pwd)/simplelogin.env:/code/.env \
    --network="sl-network" \
    simplelogin/app:3.4.0 flask db upgrade

This command could take a while to download the simplelogin/app docker image.

Init data

docker run --rm \
    --name sl-init \
    -v $(pwd)/sl:/sl \
    -v $(pwd)/simplelogin.env:/code/.env \
    -v $(pwd)/dkim.key:/dkim.key \
    -v $(pwd)/ \
    --network="sl-network" \
    simplelogin/app:3.4.0 python

Now, it's time to run the webapp container!

docker run -d \
    --name sl-app \
    -v $(pwd)/sl:/sl \
    -v $(pwd)/sl/upload:/code/static/upload \
    -v $(pwd)/simplelogin.env:/code/.env \
    -v $(pwd)/dkim.key:/dkim.key \
    -v $(pwd)/ \
    -p \
    --restart always \
    --network="sl-network" \

Next run the email handler

docker run -d \
    --name sl-email \
    -v $(pwd)/sl:/sl \
    -v $(pwd)/sl/upload:/code/static/upload \
    -v $(pwd)/simplelogin.env:/code/.env \
    -v $(pwd)/dkim.key:/dkim.key \
    -v $(pwd)/ \
    -p \
    --restart always \
    --network="sl-network" \
    simplelogin/app:3.4.0 python

And finally the job runner

docker run -d \
    --name sl-job-runner \
    -v $(pwd)/sl:/sl \
    -v $(pwd)/sl/upload:/code/static/upload \
    -v $(pwd)/simplelogin.env:/code/.env \
    -v $(pwd)/dkim.key:/dkim.key \
    -v $(pwd)/ \
    --restart always \
    --network="sl-network" \
    simplelogin/app:3.4.0 python

Install Nginx and make sure to replace by your domain

sudo apt-get install -y nginx

Then, create /etc/nginx/sites-enabled/simplelogin with the following lines:

server {

location / {
    proxy_pass http://localhost:7777;


Reload Nginx with the command below

sudo systemctl reload nginx

At this step, you should also setup the SSL for Nginx. Here's our guide how.


If all the above steps are successful, open and create your first account!

By default, new accounts are not premium so don't have unlimited alias. To make your account premium, please go to the database, table "users" and set "lifetime" column to "1" or "TRUE":

docker exec -it sl-db psql -U myuser simplelogin
UPDATE users SET lifetime = TRUE;

Once you've created all your desired login accounts, add these lines to /simplelogin.env to disable further registrations:


Then restart the web app to apply: docker restart sl-app

Donations Welcome

You don't have to pay anything to SimpleLogin to use all its features. If you like the project, you can make a donation on our Open Collective page at


The above self-hosting instructions correspond to a freshly Ubuntu server and doesn't cover all possible server configuration. Below are pointers to different topics:

❤️ Contributors

Thanks go to these wonderful people:

Dung Nguyen Van

Giuseppe Federico

Ninh Dinh

Tung Nguyen V. N.

Son Nguyen Kim

Raymond Nook

Sibren Vasse

Sylvia van Os

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