Light OpenAI Lib

A tiny, dependency-light wrapper for the OpenAI Chat Completions API. It extracts the reusable client that powers several of my Ruby projects and packages it as a gem so it can be reused without copy/paste.

Add the gem to your Gemfile:

gem "light-openai-lib"

and run bundle install.

If you are not using Bundler install it directly:

gem install light-openai-lib

require "light/openai"

client = Light::OpenAI::Client.new(
  api_key: ENV.fetch("OPENAI_API_KEY"),
  logger: Logger.new($stdout)
)

response = client.chat(
  model: "gpt-4o-mini",
  messages: [
    { role: "system", content: "You are a helpful assistant." },
    { role: "user", content: "Tell me a joke about Ruby." }
  ],
  temperature: 0.4
)

puts response.dig("choices", 0, "message", "content")

Environment variables control sane defaults:

You can also pass response_format: to #chat to opt into JSON mode. If the OpenAI API responds with a response_format error the client automatically falls back to a standard request and returns the first success payload.

This repo carries runnable scripts under examples/. The simplest one invokes the client with your OpenAI key:

OPENAI_API_KEY=sk-... bundle exec ruby examples/chat.rb "Explain compounding interest like I'm 12"

• Ruby 3.0+
• No runtime dependencies besides httparty

After checking out the repo, run:

bundle install
bundle exec rake test

bin/console gives you a REPL with the gem loaded. Update the version in lib/light/openai/version.rb before publishing, then build and push:

bundle exec rake build
gem push pkg/light-openai-lib-<version>.gem