For the complete documentation index, see llms.txt. Markdown versions of all docs pages are available by appending .md to any docs URL.
Backend TLS
Verified : Code examples on this page have been automatically tested and verified.Configure TLS for secure connections to backend services.
Attaches to:
Note
Agentgateway supports more than one configuration style. Where a feature can also be configured in the simplified llm or mcp modes, the examples on this page show each option in tabs. For more information, see Routing-based configuration.
By default, requests to backends use HTTP. To use HTTPS, configure a backend TLSTLS (Transport Layer Security)A cryptographic protocol that provides secure communication over a network. Agentgateway supports TLS for both incoming connections (listeners) and outgoing connections (backends). policy.
# yaml-language-server: $schema=https://agentgateway.dev/schema/config
mcp:
port: 3000
policies:
backendTLS:
# A file containing the root certificate to verify.
# If unset, the system trust bundle will be used.
root: ./certs/root-cert.pem
# For mutual TLS, the client certificate to use
cert: ./certs/cert.pem
# For mutual TLS, the client certificate key to use.
key: ./certs/key.pem
# If set, hostname verification is disabled
# insecureHost: true
# If set, all TLS verification is disabled
# insecure: true
targets:
- name: everything
stdio:
cmd: npx
args: ["@modelcontextprotocol/server-everything"]Note
To use TLS for a custom prompt guard webhook, set target.policies.backendTLS on the webhook target instead. For more information, see Configure webhook backend policies.
Invalid backend TLS settings
If a backend TLS policy cannot be built, requests that use that backend fail with HTTP 503. This fail-closed behavior applies in the following cases:
- The certificate files are invalid.
- The hostname or Subject Alternative Name (SAN) settings cannot be used.
- The crypto provider does not allow a configured key exchange group.
The proxy records a warning such as invalid backend TLS policy, requests to the backend will fail: <error>. The proxy does not connect to the backend in plaintext. An invalid update to a previously working backend TLS policy also fails closed.
