LLM Observer 🛡️

Privacy-first, local-only LLM cost tracking for developers.

Stop sending your prompt data to SaaS observability tools. LLM Observer runs entirely on your machine — tracks every OpenAI, Anthropic, Gemini, Mistral, and Groq call, calculates exact costs, and visualises everything in a real-time dashboard at localhost:4001.

Your API keys, prompts, and responses never leave your machine.

Quick start

npx llm-observer start

That's it. Proxy starts on port 4000, dashboard on port 4001.

How it works

Point your existing LLM code at the local proxy instead of the provider directly:

OpenAI (Node.js)

import OpenAI from 'openai';

const openai = new OpenAI({
  apiKey: 'your-actual-key',           // still goes here, stored locally
  baseURL: 'http://localhost:4000/v1/openai',
});

Anthropic (Node.js)

import Anthropic from '@anthropic-ai/sdk';

const anthropic = new Anthropic({
  apiKey: 'your-actual-key',
  baseURL: 'http://localhost:4000/v1/anthropic',
});

Google Gemini

baseURL: 'http://localhost:4000/v1/google'

Mistral / Groq / Ollama (local)

baseURL: 'http://localhost:4000/v1/mistral'
baseURL: 'http://localhost:4000/v1/groq'
baseURL: 'http://localhost:4000/v1/custom/http%3A%2F%2Flocalhost%3A11434'

Every request is intercepted, logged, costed, and shown in the dashboard — zero changes to your application logic.

Features

🔒 100% Private

All data stored in a local SQLite database at ~/.llm-observer/data.db. No telemetry. No third-party servers. Your prompts and API keys never leave your machine.

📊 Real-time dashboard

Live cost counter, request log with filters, latency tracking, model breakdown charts, and cost trajectory over 7 days — all at http://localhost:4001.

🛡️ Budget guard

Set a daily budget per project. When spend hits the limit, the proxy automatically blocks new requests before you wake up to a $1,000 bill.

llm-observer budget set 5.00 --daily

🚨 Anomaly detection

Automatic spike detection — if your spend velocity exceeds 5× your rolling average, an alert fires via webhook (Slack, Discord, or any HTTP endpoint).

💡 Cost optimizer

Identifies duplicate prompts, suggests cheaper model alternatives, and calculates potential monthly savings from switching specific call patterns.

🔌 6 providers supported

OpenAI · Anthropic · Google Gemini · Mistral · Groq · Custom/Local (Ollama, LM Studio, any OpenAI-compatible endpoint)

📦 80+ models priced

Full pricing database for GPT-4o, GPT-4o-mini, o1, o3, Claude Opus/Sonnet/Haiku, Gemini 2.5 Pro/Flash, Mistral, Groq, DeepSeek, Llama, Qwen, and more.

CLI commands

llm-observer start              # Start proxy + dashboard
llm-observer stop               # Stop all services
llm-observer status             # Show current status and today's spend

llm-observer stats              # Cost breakdown by model (today/week/month)
llm-observer logs               # Live tail of requests
llm-observer logs --provider openai --min-cost 0.01

llm-observer projects list      # List all projects
llm-observer projects create    # Create a new project (interactive)

llm-observer budget set 10.00   # Set $10/day budget on default project
llm-observer config view        # View current configuration

llm-observer export --format csv --range 30d   # Export last 30 days
llm-observer export --format json --range all

llm-observer activate <key>     # Activate Pro license
llm-observer upgrade            # View Pro plans and pricing

Dashboard pages

| Page | What it shows | |---|---| | Overview | Today's spend vs budget, request count, avg latency, error rate, 7-day cost chart | | Live Traffic | Every request in real-time via SSE — provider, model, tokens, cost, latency, status | | Insights | Cost optimizer suggestions, duplicate prompt detection, model downgrade opportunities | | Projects | Multi-project cost isolation — separate budgets per app or environment | | Alerts | Webhook alert rules for budget thresholds and anomaly spikes | | Settings | API key management, proxy config, license activation |

Pricing

| Plan | Price | Features | |---|---|---| | Free | $0 forever | 1 project · 7-day log retention · Budget guard · Anomaly alerts | | Pro | $19/mo | Unlimited projects · 90-day retention · Cost optimizer · CSV/PDF export · Priority support | | Pro (India) | ₹1,499/mo | Same as Pro, billed via Razorpay | | Team | $49/seat/mo | Everything in Pro + encrypted team sync + shared dashboard |

llm-observer upgrade            # View plans
llm-observer upgrade --india    # Indian pricing via Razorpay
llm-observer activate <key>     # Activate after purchase

Why not Helicone, Langfuse, or LangSmith?

| | LLM Observer | Helicone | Langfuse | LangSmith | |---|---|---|---|---| | Data stays local | ✅ Always | ❌ Cloud | ❌ Cloud | ❌ Cloud | | No account required | ✅ | ❌ | ❌ | ❌ | | Works offline | ✅ | ❌ | ❌ | ❌ | | Your prompts exposed | Never | To their servers | To their servers | To their servers | | Free tier | Unlimited local | Limited | Limited | Limited |

If you're working on anything sensitive — client data, proprietary prompts, internal tooling — LLM Observer is the only observability tool where your data genuinely never leaves your machine.

Requirements

• Node.js 18+
• macOS / Linux / Windows

Configuration

Config stored at ~/.llm-observer/config.json.

llm-observer config view          # See all settings
llm-observer config set webhook_url https://hooks.slack.com/...
llm-observer config set proxy_port 4000
llm-observer config set dashboard_port 4001

Or set via environment variables:

PROXY_PORT=4000 DASHBOARD_PORT=4001 npx llm-observer start

Data & privacy

• All data stored locally at ~/.llm-observer/data.db (SQLite)
• Free tier: 7-day automatic log retention
• Pro tier: 90-day retention
• To delete all data: rm ~/.llm-observer/data.db
• Zero telemetry. Zero analytics. Zero outbound connections except to your configured LLM provider.

Links

• GitHub
• Issues
• npm

License

MIT © Ranjit Behera