diff --git a/.github/workflows/deploy_backend.yml b/.github/workflows/deploy_backend.yml
index 88d060571..d654843b2 100644
--- a/.github/workflows/deploy_backend.yml
+++ b/.github/workflows/deploy_backend.yml
@@ -21,4 +21,4 @@ jobs:
           name: reacherhq/backend
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
-          tags: "${{ steps.vars.outputs.GITHUB_TAG }}"
+          tags: "${{ steps.vars.outputs.GITHUB_TAG }},beta"
diff --git a/app.json b/app.json
deleted file mode 100644
index 3ff06e877..000000000
--- a/app.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-	"name": "check-if-email-exists",
-	"buildpacks": [{ "url": "emk/rust" }],
-	"description": "Check if an email address exists without sending any email, written in Rust",
-	"keywords": [
-		"email",
-		"smtp",
-		"rust",
-		"email-validation",
-		"email-verification"
-	],
-	"logo": "https://storage.googleapis.com/saasify-uploads-prod/696e287ad79f0e0352bc201b36d701849f7d55e7.svg",
-	"repository": "https://github.com/reacherhq/check-if-email-exists"
-}
diff --git a/backend/scripts/debian11.sh b/backend/scripts/debian11.sh
new file mode 100644
index 000000000..9d7389f73
--- /dev/null
+++ b/backend/scripts/debian11.sh
@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+
+# Install script of Reacher Backend on an OVH debian 11 server.
+# As a postinstall, this script is meant to be run once, but for convenience,
+# it's actually idempotent.
+
+# Fail early.
+set -e
+
+# You can change the default values of these variables inline here, or by
+# setting them in the environment before running this script, e.g.:
+# RCH_BACKEND_NAME="my-own-name" ./debian11.sh
+
+# An unique identifier for the backend.
+RCH_BACKEND_NAME=${RCH_BACKEND_NAME:-"backend1.mycompany.com"}
+# Docker Hub tag for reacherhq/backend.
+RCH_VERSION=${RCH_VERSION:-"v0.7.0"}
+# Optional: Send bug reports to a Sentry.io dashboard.
+RCH_SENTRY_DSN=${RCH_SENTRY_DSN:-}
+# Protect the backend from the public via a `x-reacher-secret` header.
+RCH_HEADER_SECRET=${RCH_HEADER_SECRET:-}
+# For the "FROM" field in emails.
+RCH_FROM_EMAIL=${RCH_FROM_EMAIL:-"hello@mycompany.com"}
+# For the "EHLO" field in emails. This should ideally match the server's
+# reverse DNS entry for optimal results.
+RCH_HELLO_NAME=${RCH_HELLO_NAME:-"backend1.mycompany.com"}
+# Timeout for SMTP connections in seconds.
+RCH_SMTP_TIMEOUT=${RCH_SMTP_TIMEOUT:-"90"}
+# Logging. Setup to "debug" to show all logs.
+RUST_LOG=${RUST_LOG:-"info"}
+
+echo "Installing Reacher backend $RCH_VERSION on host $RCH_BACKEND_NAME..."
+
+# Install Docker
+# https://docs.docker.com/engine/install/debian/
+sudo apt-get update
+sudo apt-get upgrade --yes
+sudo apt-get install \
+    ca-certificates \
+    curl \
+    gnupg \
+    lsb-release \
+    --yes
+sudo mkdir -p /etc/apt/keyrings
+curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg --yes
+echo \
+    "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian \
+    $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
+sudo apt-get update
+sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin --yes
+
+# Create `docker` group
+# https://docs.docker.com/engine/install/linux-postinstall/
+getent group docker || sudo groupadd docker
+sudo usermod -aG docker debian
+# Reload users and groups, see
+# https://superuser.com/questions/272061/reload-a-linux-users-group-assignments-without-logging-out
+sudo su - $USER << EOF
+
+# Stop all previous docker containers and images
+docker stop reacher_backend
+docker rm reacher_backend
+
+# Run the backend
+docker run -d \
+    -e RUST_LOG=$RUST_LOG \
+    -e RCH_BACKEND_NAME=$RCH_BACKEND_NAME \
+    -e RCH_SENTRY_DSN=$RCH_SENTRY_DSN \
+    -e RCH_HEADER_SECRET=$RCH_HEADER_SECRET \
+    -e RCH_FROM_EMAIL=$RCH_FROM_EMAIL \
+    -e RCH_HELLO_NAME=$RCH_HELLO_NAME \
+    -e RCH_SMTP_TIMEOUT=$RCH_SMTP_TIMEOUT \
+    -p 80:8080 \
+    --name reacher_backend \
+    reacherhq/backend:$RCH_VERSION
+
+echo "Everything set. You can close this terminal."
+EOF
diff --git a/backend/src/check.rs b/backend/src/check.rs
index d8dacff12..e4047e276 100644
--- a/backend/src/check.rs
+++ b/backend/src/check.rs
@@ -62,6 +62,10 @@ pub fn check_header() -> warp::filters::BoxedFilter<()> {
 
 	match env_var {
 		Ok(secret) => {
+			if secret.len() == 0 {
+				return warp::any().boxed();
+			}
+
 			let secret: &'static str = Box::leak(Box::new(secret));
 
 			warp::header::exact("x-reacher-secret", secret).boxed()
diff --git a/docker.sh b/docker.sh
index 63d1b3701..aabd35581 100755
--- a/docker.sh
+++ b/docker.sh
@@ -1,5 +1,7 @@
 #!/bin/ash
 
+# This is the Dockerfile's entrypoint script.
+
 # https://docs.docker.com/config/containers/multi-service_container/
 chromedriver &
 ./reacher_backend