ARBR

What is ARBR?

ARBR is a self-hosted, MIT-licensed OpenAI-compatible control plane. You point existing SDKs at one gateway; it classifies, routes, meters and governs each request before the provider sees it. It is for teams that need policy, budgets and reversible model changes across many providers, not just a proxy.

Key features

• Single OpenAI-compatible endpoint over major providers plus any OpenAI-compatible or self-hosted backend, including LiteLLM
• Per-request classify, route, meter and govern in the data path
• Policy before inference: budgets, rate limits, output guardrails, prompt-injection checks and an application kill switch
• Budget caps by application, provider, department, workflow, model or global, over a day or month, with alert, downgrade or block; a breached block cap returns 429 and outranks an explicit model pin
• Human-gated optimisation: observe traffic, surface model-switch opportunities, evaluate candidates, then shadow or canary with rollback; pinned models stay pinned
• Structured events for cost, latency, tokens and routing decisions, local dashboards or OpenTelemetry export
• Gateway API keys (prefix ab_) bind attribution and optional per-key RPM; keys shown once then stored as SHA-256
• MIT license, self-hosted; usable standalone or above LiteLLM

Who it's for

• A team running coding agents and apps across Anthropic, OpenAI, Gemini and a self-hosted endpoint who want one budget and one kill switch
• An engineering lead who will only move a workload to a cheaper model after shadow/canary evidence, not an automatic switch
• A company already on LiteLLM that needs governance, evals and measured rollouts above the proxy
• Anyone who must attribute spend by application, team and user and export that to Datadog, Grafana or Prometheus

When not to use it

Not a drop-in replacement for a simple multi-provider proxy: if you only need to fan out API keys, LiteLLM or a managed gateway is enough. Also not a hosted SaaS you can try without deploying it — the product is self-hosted, and the site's hosted option is not priced on the public page.

FAQ