Configure TLS certificate authorities

Configure TLS certificate authority (CA) validation when connecting QuestDB clients to TLS-enabled instances.

Problem

You are using a QuestDB client (Rust, Python, C++, etc.) to insert data. It works when using QuestDB without TLS, but when you enable TLS on your QuestDB instance using a self-signed certificate, you get an error of "certificate unknown".

When using the PostgreSQL wire interface, you can insert data passing sslmode=require, and it works, so you can discard any problems with QuestDB recognizing the certificate. But you need to figure out the equivalent for your ILP client.

Solution: Configure TLS CA

QuestDB clients support the tls_ca parameter, which has multiple values to configure certificate authority validation:

Option 1: Use WebPKI and OS certificate roots (recommended for production)

If you want to accept both the webpki-root certificates plus whatever you have on the OS, pass tls_ca=webpki_and_os_roots:

https::addr=localhost:9000;username=admin;password=quest;tls_ca=webpki_and_os_roots;

This will work with certificates signed by standard certificate authorities.

Option 2: Use a custom PEM file

Point to a PEM-encoded certificate file for self-signed or custom CA certificates:

https::addr=localhost:9000;username=admin;password=quest;tls_ca=pem_file;tls_roots=/path/to/cert.pem;

This is useful for self-signed certificates or internal CAs.

Option 3: Skip verification (development only)

For development environments with self-signed certificates, you might be tempted to disable verification by passing tls_verify=unsafe_off:

https::addr=localhost:9000;username=admin;password=quest;tls_verify=unsafe_off;

:::danger This is a very bad idea for production and should only be used for testing on a development environment with a self-signed certificate. It disables all certificate validation. :::

Note: Some clients require enabling an optional feature (like insecure-skip-verify in Rust) before the tls_verify=unsafe_off parameter will work. Check your client's documentation for details.

Available tls_ca values

Example: Rust client

use questdb::ingress::{Sender, SenderBuilder};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let sender = SenderBuilder::new("https", "localhost", 9000)?
        .username("admin")?
        .password("quest")?
        .tls_ca("webpki_and_os_roots")?  // Use standard CAs
        .build()
        .await?;

    // Use sender...

    sender.close().await?;
    Ok(())
}

For self-signed certificates with a PEM file:

let sender = SenderBuilder::new("https", "localhost", 9000)?
    .username("admin")?
    .password("quest")?
    .tls_ca("pem_file")?
    .tls_roots("/path/to/questdb.crt")?
    .build()
    .await?;

The examples are in Rust but the concepts are similar in other languages. Check the documentation for your specific client.

:::info Related Documentation

• QuestDB Rust client
• QuestDB Python client
• QuestDB C++ client
• QuestDB TLS configuration :::