Optimize your agent for cost and performance — with every run. An open-source LLM router that sends routine calls to open models and pays frontier prices only for the calls that earn them. Zero harness changes.

Not every agent run needs Claude Opus 4.8 — or even Claude 5. ~80% of agent workloads run just fine on cheaper open-source models without sacrificing performance. Use BitRouter alongside Claude Code (or any coding agent) to reserve your subscription budget for the calls that actually need it. Enjoy 25% off all open-source model calls on BitRouter Cloud today.

Without BitRouter, your coding agent routes every call — file reads, summaries, tool calls, scaffolding — through the same frontier model. With BitRouter, routine work goes to open models automatically; frontier models get invoked only when they're justified.

# macOS / Linux
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/bitrouter/bitrouter/releases/latest/download/bitrouter-installer.sh | sh

# Homebrew
brew install bitrouter/tap/bitrouter

# npm
npm install -g bitrouter

cargo install bitrouter

BitRouter is a local proxy between your agent and every LLM provider. One env-var swap — no harness changes required:

- OPENAI_BASE_URL=https://api.openai.com/v1   # hardwired to one provider, no fallback
+ OPENAI_BASE_URL=http://localhost:4356        # all providers, automatic failover

Set your provider API keys and start:

export OPENAI_API_KEY=sk-...    # ANTHROPIC_API_KEY / GOOGLE_API_KEY also work
bitrouter start
# Proxy running at http://localhost:4356

BitRouter auto-detects any key set in the environment — no config file needed. Point your agent runtime at http://localhost:4356 and any provider whose key is present is immediately available.

For advanced routing rules, guardrails, or multi-account failover, scaffold a config file:

bitrouter init          # writes ./bitrouter.yaml (override with `-c <path>`)
bitrouter start

Sign in to your BitRouter Cloud account from the terminal — one OAuth account covers every model the gateway offers, no upstream provider keys required:

bitrouter auth login    # RFC 8628 device flow against api.bitrouter.ai
bitrouter start         # `bitrouter` provider auto-enables once signed in

Manage keys, usage, billing, policies, and BYOK from the same CLI — see bitrouter cloud --help or CLI.md.

bitrouter start / stop / restart               # daemon lifecycle
bitrouter route <model>                        # trace how a model name resolves
bitrouter agents list / check / install        # ACP agent management
bitrouter key sign --user <id>                 # mint a scoped brvk_ API key
bitrouter auth login / logout / whoami         # BitRouter Cloud sign-in
bitrouter cloud keys / usage / billing         # manage cloud account

See CLI.md for flags, config resolution, and examples.

BitRouter ships an Agent Skill — /bitrouter — so AI coding agents can install, configure, migrate to, and troubleshoot BitRouter on their own. It lives in this repo at skills/bitrouter/, kept in sync with the code.

bitrouter skills add bitrouter        # via BitRouter's own installer
npx skills add bitrouter/bitrouter    # via the generic skills CLI

TL;DR — OpenRouter is a cloud API marketplace for humans picking models. LiteLLM is a Python proxy for unifying provider SDKs. BitRouter is a Rust-native proxy purpose-built for autonomous agents — with cross-protocol routing, MCP and ACP support, and guardrails out of the box.

BitRouter is purpose-built for autonomous agents — every feature is designed for unattended, multi-step execution rather than human-in-the-loop API access.

Agents can't retry a provider outage the way a human can. BitRouter reroutes across providers mid-run, transparently — so a rate-limit at file 140 never makes you re-pay for 139 files of work. Configure fallback chains, round-robin across multiple accounts, or let cross-protocol routing send OpenAI-format requests to an Anthropic or Google upstream automatically.

Billed per run. Now visible per run. Every agent, every model, every hop — with cost and latency attributed to the call. Query spend from the CLI without reaching for a dashboard, export to Prometheus or any OTLP backend, or trace exactly how a model name resolves before it hits the upstream with bitrouter route <model>.

One policy at the router — before requests leave your network and before responses reach your agent. Injection and output filtering, private by default. Virtual keys (brvk_) scope credentials per agent or user so no agent ever holds an upstream key directly; per-agent spend caps and loop guards keep runaway costs contained.

Pay open-source prices for the calls that don't need frontier. Route by policy: fall back to a cheaper provider when the primary exceeds a cost threshold, or pin call types to the model with the best price-to-quality ratio for that task. Scoped virtual keys let you cap what each agent or user can spend before it touches your upstream account.

Want to add a provider? Open an issue or submit a PR. Interested in a first-party integration? Email kelsenliu@bitrouter.ai or book a meeting.

Any agent runtime that speaks OpenAI or Anthropic APIs works with BitRouter out of the box — set OPENAI_BASE_URL=http://localhost:4356 and you're done. The following harnesses are tested and supported:

Building an open-source agent? Reach out at kelsenliu@bitrouter.ai or book a meeting — we offer up to 50% off for you and your community.

The full provider and harness catalog lives at github.com/bitrouter/provider-registry.

• CLI.md — full CLI reference with flags and examples
• DEVELOPMENT.md — workspace architecture and SDK internals
• CONTRIBUTING.md — contribution workflow, issue reporting, and provider updates
• CLAUDE.md — guidance for AI coding agents working in this repository
• skills/ — the /bitrouter Agent Skill (source of truth)

• Core routing engine and provider abstractions
• OpenAI, Anthropic, Google, and Amazon Bedrock adapters
• Zero-config auto-detection from environment variables
• Custom provider support (OpenAI-compatible / Anthropic-compatible)
• Cross-protocol routing (e.g. OpenAI format → Anthropic provider)
• MCP gateway and ACP agent integration
• Multiple accounts per provider — failover + load-balancing
• Virtual key management (bitrouter key) backed by SQLite / PostgreSQL / MySQL
• Telemetry and usage analytics
• Provider & model routing policy customization

Licensed under the Apache License 2.0.