diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 13d8a7c..4bfbfdb 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -114,7 +114,7 @@ Developer pushes to hantim-server
   -> deploy-<app>.yml triggers (based on changed paths under docker/<app>/)
     -> SSH to deploy@hantim as deploy-<app>
       -> deploy.sh: git pull, docker compose pull, docker compose up -d
-      -> (nginx only): test config with nginx -t before applying
+      -> (nginx only): auto-issues certs for new domains, then tests config with nginx -t
 ```
 
 ### Setup change (push to hantim-server)
@@ -131,7 +131,10 @@ Developer pushes change to scripts/configure.sh
 - **App name = domain** (e.g., `hcsuzuki.net`)
 - **Container name** = domain with dots replaced by underscores (e.g.,
   `hcsuzuki_net`)
-- **Cert name** = domain (stored at `/etc/letsencrypt/live/<domain>/`)
+- **Cert name** = config filename without `.conf` (stored at `/etc/letsencrypt/live/<name>/`)
+- **One domain per conf file** -- `deploy.sh` derives the cert name from the conf
+  filename and collects all `server_name` values for that cert. Putting unrelated
+  domains in the same conf file will bundle them into one cert incorrectly.
 - **Image name** = `git.timothykim.net/hantim/<domain>:latest`
 - All HTTP traffic redirects to `https://www.<domain>`
 - Bare domain HTTPS redirects to `https://www.<domain>`
diff --git a/CLAUDE.md b/CLAUDE.md
index c2b6c57..d92ff0b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -24,7 +24,8 @@ Actions workflows.
 - **App name = domain** (e.g., `hcsuzuki.net`)
 - **Container name** = domain with dots replaced by underscores (e.g., `hcsuzuki_net`)
 - **Image** = `git.timothykim.net/hantim/<domain>:latest`
-- **Cert name** = domain (at `/etc/letsencrypt/live/<domain>/`)
+- **Cert name** = config filename without `.conf` (at `/etc/letsencrypt/live/<name>/`)
+- **One domain per conf file** -- deploy.sh derives cert name from filename
 - All HTTP redirects to HTTPS; bare domain redirects to `www.<domain>`
 - The `shared` Docker network is created by nginx compose and used by all apps
 
diff --git a/USECASES.md b/USECASES.md
index 56cbf3d..cc3a350 100644
--- a/USECASES.md
+++ b/USECASES.md
@@ -119,9 +119,16 @@ git push
 **What happens:**
 1. `deploy-nginx.yml` workflow triggers (path match)
 2. `deploy.sh` pulls latest code
-3. Tests nginx config with `nginx -t` -- if it fails, deploy aborts and the
+3. If any conf files reference certs that don't exist yet, nginx is briefly
+   stopped and certs are issued via standalone certbot (auto-restarts on failure)
+4. Tests nginx config with `nginx -t` -- if it fails, deploy aborts and the
    running nginx is untouched
-4. Runs `docker compose up -d` and reloads nginx
+5. Runs `docker compose up -d` and reloads nginx
+
+**Note:** Each conf file must contain server blocks for only one domain. The
+cert name is derived from the filename (e.g. `hcsuzuki.net.conf` -> cert
+`hcsuzuki.net`). Redirect-only domains like `hcsuzukiviolin.com` get their
+own conf file.
 
 ## 7. Re-run configure on existing server
 
diff --git a/scripts/deploy.sh b/scripts/deploy.sh
index d18de4e..016d097 100755
--- a/scripts/deploy.sh
+++ b/scripts/deploy.sh
@@ -54,7 +54,34 @@ if ! docker compose pull; then
 fi
 
 if [ "$APP" = "nginx" ]; then
-    # Test config before applying — a bad config (e.g. missing cert) would take down all sites
+    # Issue certs for any new domains (brief nginx downtime while certbot binds port 80)
+    missing_certs=false
+    for conf in /opt/hantim/docker/nginx/conf.d/*.conf; do
+        cert_name=$(basename "$conf" .conf)
+        if [ ! -d "/etc/letsencrypt/live/$cert_name" ]; then
+            missing_certs=true
+            break
+        fi
+    done
+    if [ "$missing_certs" = true ]; then
+        docker stop nginx 2>/dev/null || true
+        trap 'docker start nginx 2>/dev/null || true' EXIT
+        for conf in /opt/hantim/docker/nginx/conf.d/*.conf; do
+            cert_name=$(basename "$conf" .conf)
+            if [ ! -d "/etc/letsencrypt/live/$cert_name" ]; then
+                domains=$(grep -oP 'server_name\s+\K[^;]+' "$conf" | tr ' ' '\n' | sort -u)
+                domain_args=""
+                for d in $domains; do
+                    domain_args="$domain_args -d $d"
+                done
+                echo "Issuing cert for $cert_name..."
+                certbot certonly --standalone --non-interactive --agree-tos \
+                    --register-unsafely-without-email --cert-name "$cert_name" $domain_args
+            fi
+        done
+        trap - EXIT
+    fi
+    # Test config before applying — a bad config would take down all sites
     docker compose run --rm -T nginx nginx -t
 fi