LLM Cost Tracker

Self-hosted LLM cost tracking for Rails.

Every call your app makes to OpenAI, Anthropic, Gemini, RubyLLM, or any OpenAI-compatible API gets logged: tokens, cost, latency, tags. Calls go app → provider direct. No proxy.

Not Langfuse, Helicone, or LiteLLM. No prompts, no traces, no replay. Spend attribution only.

Requires Ruby 3.4+, Rails 7.1+, PostgreSQL or MySQL.

Quickstart

# Gemfile
gem "llm_cost_tracker"
gem "openai"

bin/rails llm_cost_tracker:setup

That runs the install generator with the dashboard and pricing snapshot, migrates the database, then verifies via llm_cost_tracker:doctor.

# config/initializers/llm_cost_tracker.rb
LlmCostTracker.configure do |config|
  config.default_tags = -> { { environment: Rails.env } }
  config.instrument :openai
end

Tag your calls — that's how you find out who burned the money:

LlmCostTracker.with_tags(user_id: Current.user&.id, feature: "chat") do
  client = OpenAI::Client.new(api_key: ENV["OPENAI_API_KEY"])
  client.responses.create(model: "gpt-4o", input: "Hello")
end

Mount the dashboard at /llm-costs and put it behind your app's auth — it ships without one.

What lands in the ledger

• Calls. Provider, model, total tokens, total cost, latency, status.
• Line items. Per-component breakdown — text/audio/cached tokens, tool charges (web search, code execution, grounding, container sessions).
• Tags. Whatever attribution you pass — user, feature, tenant, env.
• Provider IDs. Response, project, API key, workspace — for downstream audits.
• Pricing snapshot. So historical numbers don't drift when prices change.

Capture surfaces

Surface	Path
OpenAI	Official SDK or Faraday
Anthropic	Official SDK or Faraday
Google Gemini	Faraday
RubyLLM	Provider layer
ruby-openai	Faraday
OpenRouter, DeepSeek, Groq, LiteLLM-style gateways	OpenAI-compatible Faraday
Anything else	LlmCostTracker.track

Streams capture when the provider emits final usage. OpenAI Faraday streams need stream_options: { include_usage: true }.

What it isn't

• No proxy. Direct calls only.
• No prompts. Token counts and metadata only.
• Not invoice-grade. Provider response IDs are stored for reconciliation.
• Not multi-service. Built for a Rails monolith.

Manual tracking

For batch jobs, internal gateways, or anything without an SDK/Faraday hook:

LlmCostTracker.track(
  provider: :anthropic,
  model: "claude-sonnet-4-6",
  tokens: { input: 1500, output: 320 },
  tags: { feature: "summarizer", user_id: current_user.id }
)

Docs

• Configuration
• Pricing
• Budgets
• Data model
• Querying
• Dashboard
• Streaming
• Cookbook
• Extending
• Operations
• Architecture
• Upgrading
• Changelog

Development

bundle install
bin/check

License

MIT — see LICENSE.txt.