---
title: "Ruby | Speedscale Docs"
description: "Ruby guidance for Speedscale and proxymock, including proxy setup, TLS trust, demo app details, and a first-success workflow."
canonical: "https://docs.speedscale.com/reference/languages/ruby/"
---

[Documentation index](https://docs.speedscale.com/reference/llms.txt) | [Markdown](https://docs.speedscale.com/reference/languages/ruby/index.md) | [Canonical page](https://docs.speedscale.com/reference/languages/ruby/)

# Ruby

Ruby is fully supported by Speedscale. Use this page for Ruby-specific proxy settings, TLS trust configuration, demo guidance, and the proxymock local workflow.

*   Support matrix: [Technology Support](https://docs.speedscale.com/reference/technology-support/)
*   Shared proxymock proxy reference: [Language Configuration](https://docs.speedscale.com/proxymock/getting-started/language-reference/)

<a id="kubernetes-sidecar"></a>

## Kubernetes Sidecar

When Ruby runs with the Speedscale sidecar in `forward` or `dual` mode, the Ruby runtime must still send outbound traffic to the sidecar. Set `HTTP_PROXY` and `HTTPS_PROXY` to `http://127.0.0.1:4140` unless you changed `proxy-out-port`. Ruby's standard-library `Net::HTTP` reads these variables by default.

If `tls-out` is enabled, trust and routing are separate concerns:

*   routing: `HTTP_PROXY` and `HTTPS_PROXY`
*   TLS trust: `SSL_CERT_FILE` or the language-specific trust mechanism in your image

See [Proxy Modes](https://docs.speedscale.com/getting-started/installation/sidecar/proxy-modes/) and [TLS Support](https://docs.speedscale.com/getting-started/installation/sidecar/tls/) for the shared sidecar behavior.

<a id="demo-app"></a>

## Demo App

*   Public demo: [speedscale/mock-lab](https://github.com/speedscale/mock-lab) (`languages/ruby` directory)
*   Stack: Ruby HTTP service using the standard-library `Net::HTTP` client that calls one downstream, the CNCF projects API at `https://demo-api.trafficreplay.com`
*   Local run: `ruby app.rb`
*   Quick validation: `./lab/tests/run_tests.sh --recording`

This is the canonical public Ruby demo for the proxymock quickstart and local replay workflow.

<a id="proxymock"></a>

## proxymock

Use this path for the fastest Ruby first success on a developer workstation.

1.  1. Install and initialize proxymock
    
    ```
    brew install speedscale/tap/proxymock
    proxymock init
    ```
    
    Use browser sign-in by default. Use \`proxymock init --api-key <your key>\` only for CI or other headless environments.
    
2.  2. Start recording
    
    ```
    git clone https://github.com/speedscale/mock-lab
    cd mock-lab/languages/ruby
    proxymock record -- ruby app.rb
    ```
    
    proxymock records the app while it starts the Ruby service as a child process. \`Net::HTTP\` reads the proxy environment variables proxymock sets, so no extra configuration is needed.
    
3.  3. Generate one real workflow
    
    ```
    ./lab/tests/run_tests.sh --recording
    ```
    
    Run the test driver from the repo root. It drives the requests that become the exported production-style trace.
    
4.  4. Stop the recording, then run with mocks
    
    ```
    cd mock-lab/languages/ruby
    proxymock mock -- ruby app.rb
    ```
    
    The mocked run should no longer need live outbound dependencies.
    
5.  5. Replay the same traffic against a change
    
    ```
    cd mock-lab/languages/ruby
    proxymock replay --test-against http://localhost:8080
    ```
    
    Use replay as the regression check before shipping Ruby changes.
    

<a id="tls-trust"></a>

## TLS Trust

Ruby's `Net::HTTP` honors `SSL_CERT_FILE` for trusting the proxymock CA during TLS interception. See the shared [Language Configuration](https://docs.speedscale.com/proxymock/getting-started/language-reference/#tls-trust) page for the exact command and related options.