Ruby

Rust Python Node.js WASM Java Go C# PHP Ruby Elixir Docker Homebrew C FFI License Docs
kreuzberg.dev
Discord

Universal LLM API client for Ruby. Access 143+ LLM providers through a single interface with idiomatic Ruby API and native performance.

Installation

Package Installation

Install via one of the supported package managers:

gem:

gem install liter_llm

Bundler:

gem 'liter_llm'

System Requirements

  • Ruby 3.2+ required
  • API keys via environment variables (e.g. OPENAI_API_KEY, ANTHROPIC_API_KEY)

Quick Start

Basic Chat

Send a message to any provider using the provider/model prefix:

# frozen_string_literal: true

require "liter_llm"
require "json"

client = LiterLlm::LlmClient.new(ENV.fetch("OPENAI_API_KEY"), {})

response = JSON.parse(client.chat(JSON.generate(
  model: "openai/gpt-4o",
  messages: [{ role: "user", content: "Hello!" }]
)))

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

Common Use Cases

Streaming Responses

Stream tokens in real time:

# frozen_string_literal: true

require "liter_llm"
require "json"

client = LiterLlm::LlmClient.new(ENV.fetch("OPENAI_API_KEY"), {})

chunks = JSON.parse(client.chat_stream(JSON.generate(
  model: "openai/gpt-4o-mini",
  messages: [{ role: "user", content: "Hello" }]
)))

chunks.each { |chunk| puts chunk }

Next Steps

Features

Supported Providers (143+)

Route to any provider using the provider/model prefix convention:

Provider Example Model
OpenAI openai/gpt-4o, openai/gpt-4o-mini
Anthropic anthropic/claude-3-5-sonnet-20241022
Groq groq/llama-3.1-70b-versatile
Mistral mistral/mistral-large-latest
Cohere cohere/command-r-plus
Together AI together/meta-llama/Meta-Llama-3.1-70B-Instruct-Turbo
Fireworks fireworks/accounts/fireworks/models/llama-v3p1-70b-instruct
Google Vertex vertexai/gemini-1.5-pro
Amazon Bedrock bedrock/anthropic.claude-3-5-sonnet-20241022-v2:0

Complete Provider List

Key Capabilities

  • Provider Routing -- Single client for 143+ LLM providers via provider/model prefix
  • Local LLMs — Connect to locally-hosted models via Ollama, LM Studio, vLLM, llama.cpp, and other local inference servers

  • Unified API -- Consistent chat, chat_stream, embeddings, list_models interface

  • Streaming -- Real-time token streaming via chat_stream

  • Tool Calling -- Function calling and tool use across all supporting providers

  • Type Safe -- Schema-driven types compiled from JSON schemas

  • Secure -- API keys never logged or serialized, managed via environment variables

  • Observability -- Built-in OpenTelemetry with GenAI semantic conventions

  • Error Handling -- Structured errors with provider context and retry hints

Performance

Built on a compiled Rust core for speed and safety:

  • Provider resolution at client construction -- zero per-request overhead
  • Configurable timeouts and connection pooling
  • Zero-copy streaming with SSE and AWS EventStream support
  • API keys wrapped in secure memory, zeroed on drop

Provider Routing

Route to 143+ providers using the provider/model prefix convention:

openai/gpt-4o
anthropic/claude-3-5-sonnet-20241022
groq/llama-3.1-70b-versatile
mistral/mistral-large-latest

See the provider registry for the full list.

Proxy Server

liter-llm also ships as an OpenAI-compatible proxy server with Docker support:

docker run -p 4000:4000 -e LITER_LLM_MASTER_KEY=sk-your-key ghcr.io/kreuzberg-dev/liter-llm

See the proxy server documentation for configuration, CLI usage, and MCP integration.

Documentation

Part of kreuzberg.dev.

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

Join our Discord community for questions and discussion.

License

MIT -- see LICENSE for details.