janus-ai 0.2.3

The two-faced AI routing gateway

Janus

The two-faced gateway for AI coding tools. Janus sits at the threshold of every AI call — facing the developer on one side and every provider on the other.

Janus is a local-first, single-user AI routing gateway. It exposes OpenAI/Anthropic-compatible HTTP endpoints that your coding tools (Claude Code, Codex, Cursor, Cline, ...) talk to, then translates and routes each request to 40+ AI providers — without either side needing to know the other exists.

Quickstart

# Install
pip install -e .

# Generate default config
janus config-init

# Start the server
janus serve --port 20128

Point your coding tool at http://localhost:20128/v1 and start routing.

📚 Documentation · Contributing · Changelog

Docker

# Create config in the persistent volume
mkdir -p janus-data
cp ~/.janus/config.yaml janus-data/config.yaml  # or create one with janus config-init

# Build and run
docker compose up -d

The SQLite database and config persist in ./janus-data/. Environment variables from .env are passed through for ${ENV_VAR} resolution in config.

Configuration

Janus reads YAML config from ~/.janus/config.yaml with ${ENV_VAR} token resolution. Generate a template with janus config-init.

server:
  port: 20128
  host: 127.0.0.1
  require_api_key: false

providers:
  - id: openai
    prefix: openai
    api_type: openai_compat
    base_url: https://api.openai.com/v1
    api_key: ${OPENAI_API_KEY}
    models: [gpt-4o, gpt-4o-mini, o3, o4-mini]

  - id: anthropic
    prefix: anthropic
    api_type: anthropic
    base_url: https://api.anthropic.com
    api_key: ${ANTHROPIC_API_KEY}
    models: [claude-sonnet-4-20250514, claude-opus-4-20250514]

combos:
  - name: best-effort
    models: [anthropic/claude-sonnet-4-20250514, openai/gpt-4o]

Supported Provider Types

api_type	Use For
openai_compat	Any OpenAI-compatible API (OpenAI, Groq, Together, DeepSeek, OpenRouter, Mistral, Fireworks, Perplexity, xAI, ...)
anthropic	Direct Anthropic API
gemini	Direct Google Gemini API
opencode_free	OpenCode Zen free tier

Known Provider Base URLs

Provider	base_url
OpenAI	https://api.openai.com/v1
Groq	https://api.groq.com/openai/v1
Together AI	https://api.together.xyz/v1
DeepSeek	https://api.deepseek.com/v1
OpenRouter	https://openrouter.ai/api/v1
Mistral	https://api.mistral.ai/v1
Fireworks	https://api.fireworks.ai/inference/v1
Perplexity	https://api.perplexity.ai
xAI (Grok)	https://api.x.ai/v1
Qwen/DashScope	https://dashscope.aliyuncs.com/compatible-mode/v1

Client Setup

Point your coding tools at Janus:

Claude Code / Anthropic tools:

export ANTHROPIC_BASE_URL=http://localhost:20128/v1

OpenAI tools (Codex, Cursor, etc.):

export OPENAI_BASE_URL=http://localhost:20128/v1
export OPENAI_API_KEY=sk-janus-yourkey  # if require_api_key is on

Features

• Fallback routing — multi-account rotation with cooldowns (429->60s, 5xx->30s, auth->300s, network->15s)
• Combos — named ordered model sequences (e.g., "model": "best-effort")
• Token savers — RTK compression (default ON), Caveman terse prompt, Ponytail lazy-dev prompt
• Budgets — daily spending limits per API key or global, with warn/block thresholds
• Analytics — cost tracking, spend trends, success rates, per-model/provider/key breakdowns
• Pricing — 28 builtin model prices, YAML-overridable, cache token rates
• Dashboard — HTMX UI at /dashboard with charts, budget management, usage stats

CLI Reference

Command	Description
janus serve	Start the gateway server
janus config-init	Generate default config YAML
janus config-path	Print config file path
janus keys create/list/revoke	Manage API keys
janus usage stats/cost/by-key	Usage and cost reports
janus budgets list/set/delete	Manage spending budgets
janus pricing list/show	View model pricing

Development

git clone https://github.com/amanverasia/Janus.git
cd Janus
python -m venv .venv
pip install -e ".[dev]"

# Run tests
.venv/bin/python -m pytest

# Lint + typecheck
.venv/bin/ruff check src/janus/ tests/
.venv/bin/mypy src/janus/

# Start dev server
.venv/bin/janus serve --port 20128 --reload

Tech Stack

Python 3.11+ / FastAPI / httpx / Pydantic v2 / aiosqlite / Jinja2 / HTMX / Chart.js

License

GPL-3.0 © 2026 Aman Verasia