diff --git a/.devcontainer/docker-compose.yml b/.devcontainer/docker-compose.yml
index dcafb8a..2b58180 100644
--- a/.devcontainer/docker-compose.yml
+++ b/.devcontainer/docker-compose.yml
@@ -17,6 +17,7 @@ services:
       VAULT_CREATE_ROOT: true
       VAULT_ROOT_CA_MOUNT: pki
       VAULT_ROOT_CA_REF: root-ca
+      VAULT_SSL_CERT: cert/vault.pem
       JWT_SIGNING_KEY: jwt_secret
       APP_REGISTRY_ADDR: http://app_registry:8800
       APP_REGISTRY_TOKEN: app_reg_token
@@ -26,9 +27,26 @@ services:
     restart: unless-stopped
     ports:
       - 8200:8200
+      - 8443:8443
+    volumes:
+      - ../cert:/vault/cert
     environment:
       VAULT_DEV_ROOT_TOKEN_ID: root_token
-      VAULT_DEV_LISTEN_ADDRESS: 0.0.0.0:8200
+      VAULT_LOCAL_CONFIG: >
+        {
+            "listener": [
+                {
+                    "tcp": {
+                        "address": "0.0.0.0:8443",
+                        "tls_disable": "0",
+                        "tls_cert_file": "/vault/cert/vault.pem",
+                        "tls_key_file": "/vault/cert/vault.key"
+                    }
+                }
+            ],
+            "default_lease_ttl": "168h",
+            "max_lease_ttl": "720h"
+        }
 
   app_registry:
     image: node:latest
diff --git a/README.md b/README.md
index 26177f6..00ca829 100644
--- a/README.md
+++ b/README.md
@@ -61,3 +61,29 @@ docker build -t astral:latest .
 ```
 docker run -p 3000:3000 astral:latest
 ```
+
+# Configuration
+Astral is configured in `config/astral.yml` -- all availble
+configuration options are listed in the `shared` section. Note that
+configuration values can be supplied in this file or as process
+environment variables with the same names (but
+UPPER_CASE). Environment vars will override any values in the config
+file.  Per-environment settings in the config file(development, test,
+production) will override the shared values for that type.
+
+## mTLS connections
+Astral can connect to Vault with mTLS. Just
+set the following values in `config/astral.yml`:
+```
+  vault_ssl_cert:
+  vault_ssl_client_cert:
+  vault_ssl_client_key:
+```
+A self-signed server cert for Vault can be generated with the following 
+command:
+```
+rake configure:ssl
+```
+
+To use SSL in the devcontainer, edit `.devcontainer/docker-compose.yml` so
+that the `app` service has `VAULT_ADDRESS` of `https://vault:8443`. 
diff --git a/app/lib/clients/vault.rb b/app/lib/clients/vault.rb
index 5f0c5e0..10ec7d9 100644
--- a/app/lib/clients/vault.rb
+++ b/app/lib/clients/vault.rb
@@ -14,7 +14,10 @@ class << self
       def client
         ::Vault::Client.new(
           address: address,
-          token: token
+          token: token,
+          ssl_ca_cert: ssl_cert,
+          ssl_pem_file: ssl_client_cert,
+          ssl_key_file: ssl_client_key
         )
       end
 
@@ -22,6 +25,18 @@ def address
         Config[:vault_addr]
       end
 
+      def ssl_cert
+        Config[:vault_ssl_cert]
+      end
+
+      def ssl_client_cert
+        Config[:vault_ssl_client_cert]
+      end
+
+      def ssl_client_key
+        Config[:vault_ssl_client_key]
+      end
+
       def enable_engine(mount, type)
         client.sys.mount(mount, type, "#{type} secrets engine")
       end
diff --git a/cert/.keep b/cert/.keep
new file mode 100644
index 0000000..e69de29
diff --git a/cert/vault.csr b/cert/vault.csr
new file mode 100644
index 0000000..3b882f7
--- /dev/null
+++ b/cert/vault.csr
@@ -0,0 +1,27 @@
+-----BEGIN CERTIFICATE REQUEST-----
+MIIElzCCAn8CAQAwUjELMAkGA1UEBhMCVVMxDzANBgNVBAgMBkRlbmlhbDEUMBIG
+A1UEBwwLU3ByaW5nZmllbGQxDDAKBgNVBAoMA0RpczEOMAwGA1UEAwwFdmF1bHQw
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+JCy4FPyt1+iqfDzjtS74h261lVm6bHnW+7bI
+-----END CERTIFICATE REQUEST-----
diff --git a/cert/vault.key b/cert/vault.key
new file mode 100644
index 0000000..20ddc1b
--- /dev/null
+++ b/cert/vault.key
@@ -0,0 +1,52 @@
+-----BEGIN PRIVATE KEY-----
+MIIJQwIBADANBgkqhkiG9w0BAQEFAASCCS0wggkpAgEAAoICAQC4GT1p/wZyxvMs
+Z/N7g6HbSNqTCA6W+JbPryhy2YjVwdH+JwYQGy4GbXYxbKZp5ZXAf5/9/y6j8Bns
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+7sscXOjF3wtZdFCFacS9FPm9KRjD7AU=
+-----END PRIVATE KEY-----
diff --git a/cert/vault.pem b/cert/vault.pem
new file mode 100644
index 0000000..b7c6371
--- /dev/null
+++ b/cert/vault.pem
@@ -0,0 +1,30 @@
+-----BEGIN CERTIFICATE-----
+MIIFKzCCAxMCFDxrZQdK60TK6QxY01Y0QdRFrbdpMA0GCSqGSIb3DQEBCwUAMFIx
+CzAJBgNVBAYTAlVTMQ8wDQYDVQQIDAZEZW5pYWwxFDASBgNVBAcMC1NwcmluZ2Zp
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+sYs2JyeEa3Dpf7qU6uHbg8TWEfZsulezprneVmgG4Q==
+-----END CERTIFICATE-----
diff --git a/config/astral.yml b/config/astral.yml
index a574607..15eda38 100644
--- a/config/astral.yml
+++ b/config/astral.yml
@@ -1,23 +1,34 @@
+# Astral configuration
+# Note that values can be supplied here or as environment vars (UPPER_CASE).
 shared:
-  vault_addr: 
   vault_token:
+  vault_addr:
+  # if VAULT_ADDR is https with self-signed cert, need to provide
+  # CA cert (path to file) in "vault_ssl_cert" below:
+  vault_ssl_cert:
+  # Vault client cert if required (path to file)
+  vault_ssl_client_cert:
+  vault_ssl_client_key:
 
-  # Pre-existing root CA, or create new if requested
+  # Vault PKI configuration -- create root CA when true, or reference an existing
   vault_create_root: true
   vault_root_ca_ref: root_ca
   vault_root_ca_mount: pki_root
+  cert_ttl:
 
   jwt_signing_key:
-  cert_ttl:
 
+  # When using AppRegistry for Domain Ownership information
   app_registry_addr:
   app_registry_token:
   app_registry_ca_file:
   app_registry_client_cert:
   app_registry_client_key:
 
+  # User activity logging
   audit_log_file: <%= "#{Rails.root.join('log')}/astral-audit.log" %>
 
+# Per-environment overrides of shared configs
 test:
   cert_ttl: <%= 24.hours.in_seconds %>
 
diff --git a/lib/tasks/configure.rake b/lib/tasks/configure.rake
new file mode 100644
index 0000000..80ad985
--- /dev/null
+++ b/lib/tasks/configure.rake
@@ -0,0 +1,17 @@
+require "rake"
+
+# Rake tasks for making a vault cert
+namespace :configure do
+  desc "Make the server cert for vault"
+  task :ssl do
+    %x(
+      openssl req -new -newkey rsa:4096 -nodes \
+        -keyout cert/vault.key -out cert/vault.csr \
+        -subj "/C=US/ST=Denial/L=Springfield/O=Dis/CN=vault"
+      openssl x509 -req -days 365 -in cert/vault.csr \
+        -signkey cert/vault.key \
+        -out cert/vault.pem
+    )
+    puts "SSL key for vault created"
+  end
+end
diff --git a/lib/tasks/redoc.rake b/lib/tasks/redoc.rake
index 8810fa6..0452fc6 100644
--- a/lib/tasks/redoc.rake
+++ b/lib/tasks/redoc.rake
@@ -6,8 +6,8 @@ namespace :redoc do
   task :bundle do
     %x(
       docker run -v /workspaces/astral/doc/openapi:/data -w /data \
-      redocly/cli bundle openapi.yml \
-      --output openapi-bundled.yml
+        redocly/cli bundle openapi.yml \
+        --output openapi-bundled.yml
     )
     puts "openapi.yml and references bundled to openapi-bundled.yml"
   end
diff --git a/test/lib/clients/vault_test.rb b/test/lib/clients/vault_test.rb
index e18337c..51ca0a8 100644
--- a/test/lib/clients/vault_test.rb
+++ b/test/lib/clients/vault_test.rb
@@ -115,7 +115,10 @@ class VaultTest < ActiveSupport::TestCase
   def vault_client
     ::Vault::Client.new(
           address: vault_addr,
-          token: vault_token
+          token: vault_token,
+          ssl_ca_cert: ssl_cert,
+          ssl_pem_file: ssl_client_cert,
+          ssl_key_file: ssl_client_key
     )
   end
 
@@ -126,4 +129,16 @@ def vault_addr
   def vault_token
     Config[:vault_token]
   end
+
+  def ssl_cert
+    Config[:vault_ssl_cert]
+  end
+
+  def ssl_client_cert
+    Config[:vault_ssl_client_cert]
+  end
+
+  def ssl_client_key
+    Config[:vault_ssl_client_key]
+  end
 end