Skip to content

HTTPS Support

The RPC server supports TLS to allow HTTPS requests, as well as optional client certificates. To enable TLS, the node must first be built with the NANO_SECURE_RPC cmake cache flag set to ON.

OpenSSL must be installed. When running cmake initially, you may need to set -DOPENSSL_ROOT_DIR as well, depending on your system.

Support for secure WebSockets (wss://) is also available as of V23.0 with these build settings and configuration updates. See Secure Websockets for more details.


The following section enables TLS in config-rpc.toml for V22.1 and earlier:


or in config-tls.toml for V23.0 and later:


Testing with a self-signed server certificate

The server_cert_path setting can be a single server certificate, or a chain file if using an intermediate CA.

In this test, we'll generate a self-signed certificate. There are many ways to do this, but here we use openssl's req command to generate a certificate and a password protected keyfile:

openssl req -newkey rsa:2048 -keyout server.key.pem -x509 -days 3650 -out server.cert.pem

The passphrase must match the server_key_passphrase toml config setting. Pass -nodes if you don't want a password.

OpenSSL will now ask you for certification details. For the server cert, only Common Name is important. Make sure you set it to the fully qualified domain name. While testing, you should add this domain name to your hosts file.

Country Name (2 letter code) []:US
State or Province Name (full name) []:
Locality Name (eg, city) []:
Organization Name (eg, company) []:MyNanoRPCServer
Organizational Unit Name (eg, section) []:MyNanoThing
Common Name (eg, fully qualified host name) []
Email Address []:

We also need to generate a Diffie-Hellman params file:

openssl dhparam -out dh1024.pem 1024

Test call

Create a POST request to with the following body:

    "action": "block_count"

If using curl, self-signed certificates requires the --insecure flag.

Client certificates (optional)

If a directory is specified in client_certs_path, only clients with trusted client certificates will be able to connect. By trusted, we mean any client with a client certificate that's also installed in client_certs_path.

Revoking access can be done by removing the client certificate file from the node.

Generate and install client certificates

Repeat the following process for each client/user you want to grant access:

openssl req -newkey rsa:2048 -nodes -keyout rpcuser1.key.pem -x509 -days 365 -out rpcuser1.cert.pem

The Common Name must be unique and should be something descriptive, like "rpc.user.1"

For efficiency reasons, the client certificate must be renamed to its subject hash (or use a softlink)

openssl x509 -in rpcuser1.cert.pem -noout -subject_hash
ln -s rpcuser1.cert.pem 0fb8533c.0

Distribute the client certificate and key file to the RPC user.

Testing client certificates with Postman

Use the full version of Postman, not the Chrome extension. In settings, select the Certificates tab. Add the cert.pem and key.pem files.

The hostname must be the same as the hostname used in Common Name when generating the server certificate. Add this hostname to your hosts file if it's different from the machine hostname.

If you get an error, check the node log file. Make sure the client certificates are installed.

Single PEM file

Some clients may want a single PEM file:

cat rpcuser1.cert.pem rpcuser1.key.pem > rpcuser1.pem